Subject: Re: [teres] Stands & Vibes Date: Wed, 12 Jul 2000 01:36:39 -0700 From: phclark, phclark To: teres@aiko.com OK. I'm doing this with an architect's scale rather than calipers, but this should be close enough for gummint work. The straight sides are knurled, BTW. They are 15/16" dia. They come in four pieces, actually. Base @ dia above, just shy of .25" thick. The base is tapped for an all-threaded stud, just shy of .75" long which is designed to be threaded into a tapped hole in the point itself. I won't even guess about the thread itself, but it's smaller than 1/4". The point has approx. .25" straight sides, then a conical portion about 7/16" high. Do the geometry yourself, it looks to be about 60 degrees, perhaps less. These three pieces collapsed fully are 1 3/16" high. The fourth piece is similar to the base, but it has a small indentation machined in the center of one flat surface to take the point of the point, so to speak, to prevent it from shifting. I recall some double stick pads, but these are long gone, I've had these points for five or six years. When they are new, they're reasonably attractive, as these things go, and they are solid. Depending on application, they're a bitch to use if you don't use the double stick pad because they're tippy in one orientation and impossible in the other. I use them in drilled recesses in the feet of my speakers which makes it harder still, but that does hide them, and enables me to take more advantage of the joyous floor bounce from my floor level vents. Hope that helps. Peter C ----- Original Message ----- From: "Igor Kuznetsoff" To: Sent: Tuesday, July 11, 2000 9:01 PM Subject: Re: [teres] Stands & Vibes > Great! I need to know height x diameter, tip angle > (approximate good enough), adjustment range, and > perhaps some clue as to how they are put together. The > catalog pic shows them point up, leaving me to guess > how they are threaded together, and if the threaded > shaft, if that is what is used, can be extended. Some > double stick pads are shown as well, making me wonder > if that is the only way they are meant to attach. Do > you like their finish? > > Tnx, > Igor > > > --- phclark wrote: > > I have several sets of these, using 'em under my new > > speaks. What do you > > need to know? > > > > Peter C Subject: Re: [teres] Stands & Vibes Date: Wed, 12 Jul 2000 12:52:22 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Thanks, it does! About how much adjustment range? It would appear to be probably .25" to .5" depending on whether the stud's .75" is the whole stud, or what protrudes from the base. Igor --- phclark wrote: > OK. I'm doing this with an architect's scale rather > than calipers, but this > should be close enough for gummint work. > > The straight sides are knurled, BTW. They are > 15/16" dia. > > They come in four pieces, actually. Base @ dia > above, just shy of .25" > thick. The base is tapped for an all-threaded > stud, just shy of .75" long > which is designed to be threaded into a tapped hole > in the point itself. I > won't even guess about the thread itself, but it's > smaller than 1/4". The > point has approx. .25" straight sides, then a > conical portion about 7/16" > high. Do the geometry yourself, it looks to be > about 60 degrees, perhaps > less. > > These three pieces collapsed fully are 1 3/16" high. > The fourth piece is > similar to the base, but it has a small indentation > machined in the center > of one flat surface to take the point of the point, > so to speak, to prevent > it from shifting. I recall some double stick pads, > but these are long gone, > I've had these points for five or six years. > > When they are new, they're reasonably attractive, as > these things go, and > they are solid. Depending on application, they're a > bitch to use if you > don't use the double stick pad because they're tippy > in one orientation and > impossible in the other. I use them in drilled > recesses in the feet of my > speakers which makes it harder still, but that does > hide them, and enables > me to take more advantage of the joyous floor bounce > from my floor level > vents. > > Hope that helps. > > Peter C > > > > ----- Original Message ----- > From: "Igor Kuznetsoff" > To: > Sent: Tuesday, July 11, 2000 9:01 PM > Subject: Re: [teres] Stands & Vibes > > > > Great! I need to know height x diameter, tip > angle > > (approximate good enough), adjustment range, and > > perhaps some clue as to how they are put together. > The > > catalog pic shows them point up, leaving me to > guess > > how they are threaded together, and if the > threaded > > shaft, if that is what is used, can be extended. > Some > > double stick pads are shown as well, making me > wonder > > if that is the only way they are meant to attach. > Do > > you like their finish? > > > > Tnx, > > Igor > > > > > > --- phclark wrote: > > > I have several sets of these, using 'em under my > new > > > speaks. What do you > > > need to know? > > > > > > Peter C > > __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ Subject: Re: [teres] Stands & Vibes Date: Wed, 12 Jul 2000 13:41:21 -0700 From: phclark, phclark To: teres@aiko.com I purposely didn't put in adjustment range, 'cause it depends on what you're doing. The effective range is probably .5", but is weight dependent. The stud itself is .75" and almost the whole depth of the "puck" is tapped. I build *heavy* speaks, my last but ones were 230# ea. and I've never used the whole range. As an aside, since I'm not too sure what you have in mind for these points, you could get some appropriate length all-thread and extend the point as far as you cared to. If you were burying them in sand fixed at the top, I'd be drawn to the possibilities of as long a stud as practicable with alternating nuts and fender washers on the stud shaft to maximize contact area for each assembly. Very Buck Rogers, but you'd be the only one to know... My $0.02. Peter C ----- Original Message ----- From: "Igor Kuznetsoff" To: Sent: Wednesday, July 12, 2000 11:49 AM Subject: Re: [teres] Stands & Vibes > Thanks, it does! About how much adjustment range? > It would appear to be probably .25" to .5" depending > on whether the stud's .75" is the whole stud, or what > protrudes from the base. > > Igor > > --- phclark wrote: > > OK. I'm doing this with an architect's scale rather > > than calipers, but this > > should be close enough for gummint work. > > > > The straight sides are knurled, BTW. They are > > 15/16" dia. > > > > They come in four pieces, actually. Base @ dia > > above, just shy of .25" > > thick. The base is tapped for an all-threaded > > stud, just shy of .75" long > > which is designed to be threaded into a tapped hole > > in the point itself. I > > won't even guess about the thread itself, but it's > > smaller than 1/4". The > > point has approx. .25" straight sides, then a > > conical portion about 7/16" > > high. Do the geometry yourself, it looks to be > > about 60 degrees, perhaps > > less. > > > > These three pieces collapsed fully are 1 3/16" high. > > The fourth piece is > > similar to the base, but it has a small indentation > > machined in the center > > of one flat surface to take the point of the point, > > so to speak, to prevent > > it from shifting. I recall some double stick pads, > > but these are long gone, > > I've had these points for five or six years. > > > > When they are new, they're reasonably attractive, as > > these things go, and > > they are solid. Depending on application, they're a > > bitch to use if you > > don't use the double stick pad because they're tippy > > in one orientation and > > impossible in the other. I use them in drilled > > recesses in the feet of my > > speakers which makes it harder still, but that does > > hide them, and enables > > me to take more advantage of the joyous floor bounce > > from my floor level > > vents. > > > > Hope that helps. > > > > Peter C > > > > > > > > ----- Original Message ----- > > From: "Igor Kuznetsoff" > > To: > > Sent: Tuesday, July 11, 2000 9:01 PM > > Subject: Re: [teres] Stands & Vibes > > > > > > > Great! I need to know height x diameter, tip > > angle > > > (approximate good enough), adjustment range, and > > > perhaps some clue as to how they are put together. > > The > > > catalog pic shows them point up, leaving me to > > guess > > > how they are threaded together, and if the > > threaded > > > shaft, if that is what is used, can be extended. > > Some > > > double stick pads are shown as well, making me > > wonder > > > if that is the only way they are meant to attach. > > Do > > > you like their finish? > > > > > > Tnx, > > > Igor > > > > > > > > > --- phclark wrote: > > > > I have several sets of these, using 'em under my > > new > > > > speaks. What do you > > > > need to know? > > > > > > > > Peter C > > > > > > > __________________________________________________ > Do You Yahoo!? > Get Yahoo! Mail - Free email you can access from anywhere! > http://mail.yahoo.com/ > Subject: Re: [teres] Stands & Vibes Date: Thu, 13 Jul 2000 00:17:52 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Thanks! Igor --- phclark wrote: > I purposely didn't put in adjustment range, 'cause > it depends on what you're > doing. The effective range is probably .5", but is > weight dependent. The > stud itself is .75" and almost the whole depth of > the "puck" is tapped. I > build *heavy* speaks, my last but ones were 230# ea. > and I've never used the > whole range. > > As an aside, since I'm not too sure what you have in > mind for these points, > you could get some appropriate length all-thread and > extend the point as far > as you cared to. If you were burying them in sand > fixed at the top, I'd be > drawn to the possibilities of as long a stud as > practicable with alternating > nuts and fender washers on the stud shaft to > maximize contact area for each > assembly. Very Buck Rogers, but you'd be the only > one to know... > > My $0.02. > > Peter C > > > ----- Original Message ----- > From: "Igor Kuznetsoff" > To: > Sent: Wednesday, July 12, 2000 11:49 AM > Subject: Re: [teres] Stands & Vibes > > > > Thanks, it does! About how much adjustment > range? > > It would appear to be probably .25" to .5" > depending > > on whether the stud's .75" is the whole stud, or > what > > protrudes from the base. > > > > Igor > > > > --- phclark wrote: > > > OK. I'm doing this with an architect's scale > rather > > > than calipers, but this > > > should be close enough for gummint work. > > > > > > The straight sides are knurled, BTW. They are > > > 15/16" dia. > > > > > > They come in four pieces, actually. Base @ dia > > > above, just shy of .25" > > > thick. The base is tapped for an all-threaded > > > stud, just shy of .75" long > > > which is designed to be threaded into a tapped > hole > > > in the point itself. I > > > won't even guess about the thread itself, but > it's > > > smaller than 1/4". The > > > point has approx. .25" straight sides, then a > > > conical portion about 7/16" > > > high. Do the geometry yourself, it looks to be > > > about 60 degrees, perhaps > > > less. > > > > > > These three pieces collapsed fully are 1 3/16" > high. > > > The fourth piece is > > > similar to the base, but it has a small > indentation > > > machined in the center > > > of one flat surface to take the point of the > point, > > > so to speak, to prevent > > > it from shifting. I recall some double stick > pads, > > > but these are long gone, > > > I've had these points for five or six years. > > > > > > When they are new, they're reasonably > attractive, as > > > these things go, and > > > they are solid. Depending on application, > they're a > > > bitch to use if you > > > don't use the double stick pad because they're > tippy > > > in one orientation and > > > impossible in the other. I use them in drilled > > > recesses in the feet of my > > > speakers which makes it harder still, but that > does > > > hide them, and enables > > > me to take more advantage of the joyous floor > bounce > > > from my floor level > > > vents. > > > > > > Hope that helps. > > > > > > Peter C > > > > > > > > > > > > ----- Original Message ----- > > > From: "Igor Kuznetsoff" > > > To: > > > Sent: Tuesday, July 11, 2000 9:01 PM > > > Subject: Re: [teres] Stands & Vibes > > > > > > > > > > Great! I need to know height x diameter, tip > > > angle > > > > (approximate good enough), adjustment range, > and > > > > perhaps some clue as to how they are put > together. > > > The > > > > catalog pic shows them point up, leaving me to > > > guess > > > > how they are threaded together, and if the > > > threaded > > > > shaft, if that is what is used, can be > extended. > > > Some > > > > double stick pads are shown as well, making me > > > wonder > > > > if that is the only way they are meant to > attach. > > > Do > > > > you like their finish? > > > > > > > > Tnx, > > > > Igor > > > > > > > > > > > > --- phclark wrote: > > > > > I have several sets of these, using 'em > under my > > > new > > > > > speaks. What do you > > > > > need to know? > > > > > > > > > > Peter C > > > > > > > > > > > > __________________________________________________ > > Do You Yahoo!? > > Get Yahoo! Mail - Free email you can access from > anywhere! > > http://mail.yahoo.com/ > > > __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ Subject: RE: [teres] Stands & Vibes Date: Thu, 13 Jul 2000 04:46:47 -0700 From: Tony Bombera, Tony Bombera To: teres@aiko.com Hi Daus, Please do forward it. Thanks, Tony Bombera > -----Original Message----- > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > daus@ufl.edu > Sent: Tuesday, July 11, 2000 4:26 PM > To: teres@aiko.com > Subject: RE: [teres] Stands & Vibes > > > Hey everyone, > > I couldn't help but notice the talk aobut the modes of > a flat plate etc.. My design will take into account > the resonant modes of a flat panel. I am still split > between a minimalist "X" type shape that is about 4" > thick or a traditional flat panel with the motor > isolated. Factoring the construction costs in, I will > go for the flat plate, but I have a really great way to > combine good engineering materials and concepts while > maintaining asthetic appeal. My design should look > like a Wilson-Bensch design. I developed an Excel > spreadsheet that calculates the resonant modes for > different materials in a rectangular board type shape. > I also calculated our platter and, from what I can > remember, it has a resosnant frequency around 30 hz for > the first mode. If anyone is interested, I could > forward them a copy. > > Daus > Subject: Re: [teres] Stands & Vibes Date: Fri, 14 Jul 2000 11:40:40 -0700 From: PEARL Cust Serv, PEARL Cust Serv To: teres@aiko.com Daus wrote: > Hey everyone, > > I couldn't help but notice the talk about the modes of > a flat plate etc.. My design will take into account > the resonant modes of a flat panel. I am still split > between a minimalist "X" type shape that is about 4" > thick or a traditional flat panel with the motor > isolated. Factoring the construction costs in, I will > go for the flat plate, but I have a really great way to > combine good engineering materials and concepts while > maintaining aesthetic appeal. My design should look > like a Wilson-Bensch design. I developed an Excel > spreadsheet that calculates the resonant modes for > different materials in a rectangular board type shape. > I also calculated our platter and, from what I can > remember, it has a resonant frequency around 30 hz for > the first mode. If anyone is interested, I could > forward them a copy. > > Daus There is a quite competent FEA program called "Quickfield" available at quickfield.com that's a freebie, fully functional demo of their $US3500.00 app. While it's limited to 200 points, it is almost sure to be adequate for simple structures such as he ones you describe. As well, the folk at QF will take your demo file, flesh out the mesh, run that on the full version, supply you the results and charge you nothing . . . That's hard to beat for a one- or two-off set of problems Bill -PEARL, Inc. Subject: [teres] Daus's Excel Program Date: Sat, 15 Jul 2000 01:59:39 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com All, Daus asked me to offer his Excel sheet to anyone he may have missed as a result of his vacation packing frenzy. Igor His notes: Sure, the modes are basically the first, second, third, etc., harmonics of the vibrating surface. Each increasing mode is less than the preceding mode in amplitude. Yes, the first two are for the platter. They differ by the method of constraint. Just for kicks, the material I have there is Carbon Fiber. __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ --------------------------------------------------------------------- Name: Teres Design.xls Teres Design.xls Type: Microsoft Excel Worksheet (application/vnd.ms-excel) Encoding: base64 Subject: Re: [teres] Critique my design please Date: Mon, 24 Jul 2000 10:32:59 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Should work fine, Steve. I would add that Chris's aluminum plate was, IIRC, meant to terminate the chassis into sand. This should work nicely, but without sand damping the plate & draining the vibration from it, that plate acts as a vibration *"tank"*, echoing the energy around within it, some of it naturally making it back to the stylus. This is something I've warned about vis-a-vis the use of metals in a chassis. The effect of an undamped plate is deleterious, not helpful, until properly damped or sunk. The temporary MDF plate made an improvement by acting as a damper. Completing his plans, I expect that Chris will experience a much larger improvement than the partial correction the MDF can offer. Aside from that, I would suggest that bonding your damping layer across its entire surface could result in an improvement of damping efficiency if the material is relatively hard (I am not familiar with this particular formulation), unless Soundown has specifically recommended against gluing *this formulation*. Bolting it is ok, and if it is a soft material this should work well enough, but how well this layer works can depend on how intimate it is with the layers it is contacting over its *entire surface*. The problem with bolting together layers of (relatively) *harder* materials is that they tend to deform (and it takes very little bending), being tight at the bolted places, naturally, but bowing out in reaction in between, compromising the tightness of the contact area. Its just simple physics. Unless the bounding materials are pre-bowed favorably to provide pressure against the target material (your damping layer), the areas away from the bolted spots will lose contact pressure. Softer materials will just billow out in between, maintaining reasonable contact. I don't like to chance this, in any case, preferring to bond completely. The down side of bonding would be the permanency, where bolting allows you to take this arrangement apart for modification. In the case of relatively softer, therefore more compressible materials, bolting allows you to experiment with varying the amounts of compression. This is an attractive thought, but it seems like most reports on the results suggest that little improvement resulted from experimentaion with that (possibly because it turned out to be too much fuss to do enough with), even if there are so many variables in such a situation that it is possible that this can potentially be of benefit. Igor --- Thom Mackris / Joan Panzella wrote: > Simplicity ain't so bad, Steve. I'm not familiar > with Soundown DT, but > having heard Chris' crude, temporary lash-up, I can > guarantee that you'll > have a very fine 'table with your approach. Don't > neglect the stand, > however. I'm sure that a good part of what's making > Chris' lash-up sound so > good is the stand he built (which I'm in the process > of completing). > > When Chris bolted (temporarily) a piece of MDF to > the 3/16" aluminum plate, > things really began to come together. There was a > solidity to the sound and > dynamics swelled with a resolution that reminded me > of the epiphany I > experienced upon hearing my first competent singele > ended system. The > system breathed, and when appropriate, it roared. > > One comment, and take this as an educated guess and > nothing more. I would > mount the arm on the top layer (of whatever material > you choose). In other > words, whatever the bearing bolts onto is what the > arm should bolt to. Just > my .02 uf > > Cheers, > Thom > > > ----- Original Message ----- > From: steve brooks > To: > Sent: Saturday, July 22, 2000 9:48 PM > Subject: [teres] Critique my design please > > > All, > Before I start building I thought I would lay out my > design so that I may > get some feedback (to avoid it later I guess). > > Due to my sheer lack of skill and experience my > design is pretty simple. A > 14" circle of 3/4" high density MDF will hold the > bearing assembly. The next > layer will be a 14" donut (think hole in the middle > so that the bearing > assembly is not touching it directly) of 1" acrylic. > This "donut" will have > sort of an outrigger for arm mounting(think SME 10). > Between the two layers > a 1/16 layer of Soundown DT. Now the guy I talked to > at Soundown said that > for this application it would be ok to bolt all > three layers together...what > do you think? > > Of course the whole thing will have some sort of > pointy feet on bottom and > probably a sandbox underneath ( maybe a round one). > > Maybe more importantly than anything else, nothing > except the Rega tonearm > will be............black!!!! > > Comments,crticisms? > > Steve Brooks > > __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ Subject: [teres] Spindle/bearing clearances Date: Mon, 24 Jul 2000 19:31:55 -0700 From: phclark, phclark To: Teres Now that I can hold this critter on my lap... Noting that there is approx. 1" between the bottom of the platter and the beginning of the screw section of the bearing, (and acknowledging that this 1" would be most profitably spent inside something substantial with the nut just outside,) is it advisable at all to use a spacer on the ledge of the bearing (exposed about .15") in order to raise the effective height of the platter? I need about 1.25" of height additional, can/should/ought I do it this way? Peter C Subject: Re: [teres] Critique my design please Date: Mon, 24 Jul 2000 20:03:07 -0700 From: steve brooks, steve brooks To: teres@aiko.com Chris and Thom...and whoever else wants to jump in, > I agree with Thom's > suggestion that the arm board and bearing be attached to the same layer. I guess I missed something along the way...I was purposely mounting the bearing on one surface and the arm on another with damping material in between to keep vibrations from getting to the armboard (which would be some sort of constrained layer board..is this a bad idea? Steve Subject: Re: [teres] Critique my design please Date: Mon, 24 Jul 2000 20:17:46 -0700 From: Kalman Rubinson, Kalman Rubinson To: teres@aiko.com On Mon, 24 Jul 2000, steve brooks wrote: > Chris and Thom...and whoever else wants to jump in, > > > I agree with Thom's > > suggestion that the arm board and bearing be attached to the same layer. > > I guess I missed something along the way...I was purposely mounting the > bearing on one surface and the arm on another with damping material in > between to keep vibrations from getting to the armboard (which would be > some sort of constrained layer board..is this a bad idea? Basically, yes. There should be no potential for any relative movement between the platter/disc and the arm support. Kal Subject: RE: [teres] Critique my design please Date: Mon, 24 Jul 2000 20:57:42 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > I guess I missed something along the way...I was > purposely mounting the > bearing on one surface and the arm on another > with damping material in > between to keep vibrations from getting to the > armboard (which would be > some sort of constrained layer board..is this a bad idea? IMO, two questions need be asked: Whence these vibrations, and to what harm? For the record, Teres bearings are virtually noiseless (!) and the running motor should be presumed to be so also, or it's mounting still needs work. With lossy interfaces, the presumed risk is that the two surfaces move (bend, resonate) relative to one another in response to the only real remaining stimulus to a properly designed system: External noise which will be naturally centered at the frequency near the maximum acoustic power of the system, or probably around a few hundred Hz. This is a real input from outside of the system in question. (You may also include the average frequency of mechanical shock input, but then I don't regularly submit my table to mechanical shock...) Building an bandpass system by unintentionally selecting just enough mass and lossy coupling to be reactive in _this_ few hundred Hz region is concerning. If you plan to use resilient coupling of separate mounting lands for arm and platter, please consider either tremendous mass or very little mass (assuming good rigidity in both cases.) Stay away from the frequencies your hifi acoustically injects back into the front-end as a type of feedback. "Howl", they used to call it. Internal inputs, OTOH, are lower in magnitude and center at a frequency that naturally includes the RIAA curve, or perhaps the same average frequency you hear when you listen to your headshell 'cry' around a KHz. Unfortunately, your arm bears the brunt of these inputs and you are relatively powerless to do anything about it. Rigid mechanical systems couple the loop better without introducing bending of their own, thereby actually canceling resonance. Light ones do so without risking excessive excitability at primary _external_ input frequencies because they are tuned to a higher frequency. Then, you're just left with damping the system critically which is easier with each octave you gain as you raise the frequency of the resonance in question. Stopping a 15" woofer moving with a 1w input at 50Hz is harder than stopping a 1" tweeter with the same input at 10,000Hz even when the motors are identical and the acoustic levels matched... To me the question remains: What are the vibrations you want to conquer? Know your enemy and design your system accordingly. Jon Lane Subject: [teres] Request for dimensions Date: Mon, 24 Jul 2000 20:59:54 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com I'm contracting a shop to do some machining and have been at AutoCad all weekend. While the final work will be done with bearing in hand, can anyone quote me the thread dia and pitch of the brass female part? And has anyone mic'ed the smooth part of the brass shaft? (Chris, had Bryce ever quoted a tolerance for that portion?) I'm hoping to press-fit it into the chassis... TIA, Jon Lane Subject: RE: [teres] Critique my design please Date: Mon, 24 Jul 2000 21:14:01 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > The problem with bolting together layers of > (relatively) *harder* materials is that they tend to > deform (and it takes very little bending), being tight > at the bolted places, naturally, but bowing out in > reaction in between, compromising the tightness of the > contact area. Its just simple physics. Unless the > bounding materials are pre-bowed favorably to provide > pressure against the target material (your damping > layer), the areas away from the bolted spots will lose > contact pressure. Softer materials will just billow > out in between, maintaining reasonable contact. A technique that I hadn't seen discussed on the List in detail is vacuum bagging. Consider a series of laminated turntable chassis materials bonded with a suitable epoxy under the uniform force of 10-12 psi all over the surface. Any boat builder with experience in cold molding should have these resources. Users relate zero voids and very thin bonding lines - no bolts, no pressure zones. OTOH, premade laminates can be had with internal pressures many, many times higher... Jon Lane Subject: RE: [teres] Request for dimensions Date: Mon, 24 Jul 2000 22:44:17 -0700 From: Fritz Moore, Fritz Moore To: teres@aiko.com With 5-7 tenthousandths you probably shouldnt press fit the sleeve unless your going to ream to size afterwards. Fritz -----Original Message----- From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of Jon Lane Sent: Monday, July 24, 2000 7:50 PM To: teres@aiko.com Subject: [teres] Request for dimensions I'm contracting a shop to do some machining and have been at AutoCad all weekend. While the final work will be done with bearing in hand, can anyone quote me the thread dia and pitch of the brass female part? And has anyone mic'ed the smooth part of the brass shaft? (Chris, had Bryce ever quoted a tolerance for that portion?) I'm hoping to press-fit it into the chassis... TIA, Jon Lane Subject: RE: [teres] Critique my design please Date: Tue, 25 Jul 2000 00:12:53 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Vacuum bagging came up during early discussions of platter lamination. Some cabinetmakers also have the equipment. Igor --- Jon Lane wrote: > > The problem with bolting together layers of > > (relatively) *harder* materials is that they tend > to > > deform (and it takes very little bending), being > tight > > at the bolted places, naturally, but bowing out in > > reaction in between, compromising the tightness of > the > > contact area. Its just simple physics. Unless > the > > bounding materials are pre-bowed favorably to > provide > > pressure against the target material (your damping > > layer), the areas away from the bolted spots will > lose > > contact pressure. Softer materials will just > billow > > out in between, maintaining reasonable contact. > > A technique that I hadn't seen discussed on the List > in > detail is vacuum bagging. Consider a series of > laminated > turntable chassis materials bonded with a suitable > epoxy > under the uniform force of 10-12 psi all over the > surface. > Any boat builder with experience in cold molding > should have > these resources. Users relate zero voids and very > thin > bonding lines - no bolts, no pressure zones. > > OTOH, premade laminates can be had with internal > pressures > many, many times higher... > > Jon Lane > > __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ Subject: Re: [teres] Critique my design please Date: Tue, 25 Jul 2000 07:44:04 -0700 From: Thom Mackris, Thom Mackris To: teres@aiko.com Chris and I (and many others) are of the school that the distance between platter bearing and arm mount should be fixed in order to keep the relative motion between the two at an absolute minimum. Cheers, Thom ----- Original Message ----- From: steve brooks To: Sent: Monday, July 24, 2000 10:59 PM Subject: Re: [teres] Critique my design please Chris and Thom...and whoever else wants to jump in, > I agree with Thom's > suggestion that the arm board and bearing be attached to the same layer. I guess I missed something along the way...I was purposely mounting the bearing on one surface and the arm on another with damping material in between to keep vibrations from getting to the armboard (which would be some sort of constrained layer board..is this a bad idea? Steve Subject: Re: [teres] Critique my design please Date: Tue, 25 Jul 2000 08:37:01 -0700 From: ron welborne, ron welborne To: teres@aiko.com relative motion or relative vibration? If one is using a stable platform with a solid plynth and solid separate arm pedestal, I can't visualize how or see why there could be any relative motion between the arm and platter. Regards, Ron Welborne Labs wlabs@ix.netcom.com ph: 303.470.6585 fax: 303.791.5783 website --------------- www.welbornelabs.com ----------------- ----- Original Message ----- From: Thom Mackris To: Sent: Tuesday, July 25, 2000 7:38 AM Subject: Re: [teres] Critique my design please > Chris and I (and many others) are of the school that the distance between > platter bearing and arm mount should be fixed in order to keep the relative > motion between the two at an absolute minimum. > > Cheers, > Thom > > ----- Original Message ----- > From: steve brooks > To: > Sent: Monday, July 24, 2000 10:59 PM > Subject: Re: [teres] Critique my design please > > > Chris and Thom...and whoever else wants to jump in, > > > I agree with Thom's > > suggestion that the arm board and bearing be attached to the same layer. > > I guess I missed something along the way...I was purposely mounting the > bearing on one surface and the arm on another with damping material in > between to keep vibrations from getting to the armboard (which would be > some sort of constrained layer board..is this a bad idea? > > Steve > Subject: Re: [teres] Critique my design please Date: Tue, 25 Jul 2000 09:02:34 -0700 From: Kalman Rubinson, Kalman Rubinson To: teres@aiko.com On Tue, 25 Jul 2000, ron welborne wrote: > relative motion or relative vibration? I fail to see the difference here. > If one is using a stable platform with a solid plynth and solid separate arm > pedestal, I can't visualize how or see why there could be any relative > motion between the arm and platter. That assumes that each is perfectly fixed and unmoving under all conditions. BTW, while I am a fervent believer in maintaining a fixed relationship between platter and arm fixture, it is only one of many parameters that often must be hedged when there are other, over-riding concerns. Kal > > ----- Original Message ----- > From: Thom Mackris > To: > Sent: Tuesday, July 25, 2000 7:38 AM > Subject: Re: [teres] Critique my design please > > > > Chris and I (and many others) are of the school that the distance between > > platter bearing and arm mount should be fixed in order to keep the > relative > > motion between the two at an absolute minimum. > > > > Cheers, > > Thom > > > > ----- Original Message ----- > > From: steve brooks > > To: > > Sent: Monday, July 24, 2000 10:59 PM > > Subject: Re: [teres] Critique my design please > > > > > > Chris and Thom...and whoever else wants to jump in, > > > > > I agree with Thom's > > > suggestion that the arm board and bearing be attached to the same layer. > > > > I guess I missed something along the way...I was purposely mounting the > > bearing on one surface and the arm on another with damping material in > > between to keep vibrations from getting to the armboard (which would be > > some sort of constrained layer board..is this a bad idea? > > > > Steve > > > Subject: RE: [teres] Critique my design please Date: Tue, 25 Jul 2000 09:59:18 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com --- Jon Lane wrote: > > I guess I missed something along the way...I was > > purposely mounting the > > bearing on one surface and the arm on another > > with damping material in > > between to keep vibrations from getting to the > > armboard (which would be > > some sort of constrained layer board..is this a > bad idea? > > Internal inputs, OTOH, are lower in magnitude and > center at a frequency that naturally includes the >RIAA curve, or > perhaps the same average frequency you hear when you > listen to your headshell 'cry' around a KHz. > Unfortunately, your > arm bears the brunt of these inputs and you are > relatively powerless to do anything about it. Rigid >mechanical systems couple the loop better without >introducing bending of their > own, thereby actually canceling resonance. Actually, the stylus itself is a source of quite a bit of noise, and the loop back to itself through arm, chassis, then reflected back or passed on through bearing/platter (probably the lesser loop) should be considered, but decoupling the system with a compliant interface such you had planned is not a good way to do it. The platter-to-arm relationship is critical, and needs to be rigid, although rigidity does not cancel resonance, quite the opposite, it allows transmission-both forward & back. To deal with this the area of the chassis between the two (at least) can (and IMO should) be damped, but not decoupled. The arm is indeed a battlefield of noise, and difficult to quiet completely, but then that's why "arm wrap" type treatments exist, regardless of individual opinions of them. Their very existence shows that something can be done. Arms *can* be damped for quieting. My personal favorite is a polymer coating, which I have found to work better than those expensive arm wrap treatments. Additionally, they are tuneable, simply by varying the thickness of the coat, as well as location. Igor __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ Subject: Re: [teres] Critique my design please Date: Tue, 25 Jul 2000 10:38:59 -0700 From: ron welborne, ron welborne To: teres@aiko.com ----- Original Message ----- From: Kalman Rubinson To: Sent: Tuesday, July 25, 2000 8:58 AM Subject: Re: [teres] Critique my design please > On Tue, 25 Jul 2000, ron welborne wrote: > > > relative motion or relative vibration? > > I fail to see the difference here. > > > If one is using a stable platform with a solid plynth and solid separate arm > > pedestal, I can't visualize how or see why there could be any relative > > motion between the arm and platter. > > That assumes that each is perfectly fixed and unmoving > under all conditions. Absolutely! > > BTW, while I am a fervent believer in maintaining a fixed > relationship between platter and arm fixture, it is only > one of many parameters that often must be hedged when there > are other, over-riding concerns. I'm really just echoing Jon's (and other's) previous comments that the quality of the components we have to play with here are so great that the actual component induced interactions between the motor, bearing, platter, arm, etc will most likely be negligible and therefore the real enemy will be the externally induced vibrations. So IMO an attached armboard is just as good as a detached armboard provided one uses some common sense and doesn't screw up the implementation (which IS possible with either design method). I realize that I'm for the most part in the minority on this topic so digest my comments with due caution! FWIW, my design will consist of a "Y" shaped plynth with separate motor pod and arm pod all mounted on a granite surface plate and all isolated from the floor by a modified air-bearing system/stand. I see this modularity as providing some options down the road if needed. my 02 cents Ron > > Kal > > > > ----- Original Message ----- > > From: Thom Mackris > > To: > > Sent: Tuesday, July 25, 2000 7:38 AM > > Subject: Re: [teres] Critique my design please > > > > > > > Chris and I (and many others) are of the school that the distance between > > > platter bearing and arm mount should be fixed in order to keep the > > relative > > > motion between the two at an absolute minimum. > > > > > > Cheers, > > > Thom > > > > > > ----- Original Message ----- > > > From: steve brooks > > > To: > > > Sent: Monday, July 24, 2000 10:59 PM > > > Subject: Re: [teres] Critique my design please > > > > > > > > > Chris and Thom...and whoever else wants to jump in, > > > > > > > I agree with Thom's > > > > suggestion that the arm board and bearing be attached to the same layer. > > > > > > I guess I missed something along the way...I was purposely mounting the > > > bearing on one surface and the arm on another with damping material in > > > between to keep vibrations from getting to the armboard (which would be > > > some sort of constrained layer board..is this a bad idea? > > > > > > Steve > > > > > > > > Subject: Re: [teres] Critique my design please Date: Tue, 25 Jul 2000 17:38:35 -0700 From: ron welborne, ron welborne To: teres@aiko.com Hi Alexander, I have been fortunate enough to find several surplus air-casters. These casters are used for moving heavy equipment on a cushion of air. The casters I found are a very nice size 8" x 8" and so I will be able to place one under each corner of my granite plate allowing me to easily level things. For more info you can visit the manufactuer's website http://www.aerogo.com. Basically, the air caster is a 3/4" x 8" x 8" chunk of aluminum containing a few air passages and has been machined to accept an air hose fitting. A small diameter inner tube is glued to one side of the aluminum plate. Under normal use the caster is set on the floor, inner tube side down, and the load is placed on top of the aluminum plate. Air is pumped into the device and initially the inner tube inflates creating a seal against the floor and raising the caster/load. Once fully inflated, air slowly begins to escape from the center of the caster and this creates a cushion of air between the tube and the floor. A miniature hover craft! For my purposes I plan to plug the hole that allows the air to escape from the caster (I don't want to continuously run an air compressor while I spin my vinyl) and just use them as miniature air bladders. By individually adjusting the amount of air in each caster I should be able to very easily level my granite table base and of course it will also provide a degree of isolation from floor vibrations. Gordon has suggested that I build a table stand similar to Chris' and build these casters into the actual table legs. This is an excellent idea and one that I plan to pursue. I don't know what these things cost new but if there is a source for small diameter inner tubes (~6" outer diameter) one could inexpensively make something similar. Regards, Ron Welborne Labs wlabs@ix.netcom.com ph: 303.470.6585 fax: 303.791.5783 website --------------- www.welbornelabs.com ----------------- ----- Original Message ----- From: Alexander Lee To: Sent: Tuesday, July 25, 2000 1:52 PM Subject: Re: [teres] Critique my design please > Hello Ron, > > Very much interestd in how to build your air-bearing system stand. Would you > be as kind as to share with us the details of the construction. > > Best regards, > > Alexander Lee > > > > > --- ron welborne wrote: > > FWIW, my design will consist of a "Y" shaped plynth with separate motor pod > > and arm pod all mounted on a granite surface plate and all isolated from the > > floor by a modified air-bearing system/stand. I see this modularity as > > providing some options down the road if needed. > > > > my 02 cents > > > > Ron > > > > > __________________________________________________ > Do You Yahoo!? > Get Yahoo! Mail - Free email you can access from anywhere! > http://mail.yahoo.com/ Subject: Re: [teres] Critique my design please Date: Tue, 25 Jul 2000 21:12:17 -0700 From: steve brooks, steve brooks To: teres@aiko.com I've been thinking about buying a used benchtop isolation device like a Newport (when I get to sell my VPI). Maybe this could be the next project..a DIY Vibraplane. I know Newport sells the devices that they use in their benchtop model. Steve Brooks > Hello Ron, > > Very much interestd in how to build your air-bearing system stand. Would you > be as kind as to share with us the details of the construction. Subject: RE: [teres] Critique my design please Date: Tue, 25 Jul 2000 22:58:39 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > The platter-to-arm relationship is critical, and > needs to be rigid, although rigidity does not cancel > resonance, quite the opposite, it allows > transmission-both forward & back. Not necessarily: Consider a composite material chosen for both rigidity and low transmission of HF energy. Carbon fiber, graphite fiber, high-pressure materials, vs. undamped metals of the same mass. Of course, "cancel" implies an absolute and is not the word for any of these, as you know, but the _relative_ transmission is varied greatly by the materials choice. But I should have more complete: I meant to tie together the various elements of my post on this subject and say that relatively LF _external_ inputs could appear at both ends of the record playing system (to less than an absolute degree) only if the intervening material was rigid at those input frequencies. Then, the system effectively brings a degree of cancellation to those inputs. OTOH, internal chassis movement at higher frequencies can naturally create real resonance to a degree dependent on the materials and masses involved. In all cases, an understanding of the source, magnitude, and frequencies of all energy present in the chassis is the prerequisite to dealing with each and every one. Personally, I'm not too terribly concerned with bearing noise or motor rumble - the former is ultra-low, the latter is to be eliminated through adequate isolation. But we do have acoustic feedback and stylus energy to contend with... Jon Lane Subject: Re: [teres] Critique my design please Date: Tue, 25 Jul 2000 23:13:33 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com --- ron welborne wrote: > > ----- Original Message ----- > From: Kalman Rubinson > To: > Sent: Tuesday, July 25, 2000 8:58 AM > Subject: Re: [teres] Critique my design please >------------------------ > I'm really just echoing Jon's (and other's) previous > comments that the > quality of the components we have to play with here > are so great that the > actual component induced interactions between the > motor, bearing, platter, > arm, etc will most likely be negligible and > therefore the real enemy will be > the externally induced vibrations ----------------snip-------------- While it's probably rather apparent from the amount of effort I've put into promoting air suspensions, sandboxes, and various damping treatments over the course of this project, that I am quite concerned with dealing with externally induced vibrations, I thought it germane to take a moment to mention that the loudest vibration our systems will have to deal with will actually come from the stylus banging about on its way through the groove. Something to think about. Igor __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ Subject: RE: [teres] Critique my design please Date: Wed, 26 Jul 2000 00:01:53 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Jon, We're finally in agreement. That is,indeed, why I hope to build my minimal exposed area "Y"-shaped chassis using a complex composite involving carbon fiber. Stiffness & good internal loss, minimal acoustic pickup area. Also the reason why I got rather excited about finding (reasonably priced) off-the-shelf tapered carbon fiber tubes perfect for a possible attempt at substituting for metal arm tubes at: http://www.deltronix.com/public/acp/ACP-CAT.HTM With these it may be possible to take a serious shot at the stylus energy problem, something I feel has never been addressed properly. I also have some other rather innovative ideas about dealing with that, but am not ready to talk about them. As to the cancellation thing, yes, at *low* frequencies what you describe can happen. I don't remember your specifying low frequencies previously. Unfortunately, this effect would be rather limited as the moment the frequencies rise even a little, the transmission times involved and the internal reflections within the connecting materials will make such a complex mish-mosh of the energies present that a useful degree of cancellation will no longer occur. At that point damping, of any material, no matter how good it is, is necessary. There can be no disputing that "understanding the enemy" is key to dealing with vibrational, or any other problems. While rigid materials with good internal damping will certainly transmit less HF energy than undamped metal of equal mass, just as you say, compliant ones can be expected to transmit even less. They just aren't a good choice for use in the manner that got us on this subject, not having the necessary dimensional / relational stability between arm & platter, on their own. Igor --- Jon Lane wrote: > > The platter-to-arm relationship is critical, and > > needs to be rigid, although rigidity does not > cancel > > resonance, quite the opposite, it allows > > transmission-both forward & back. > > Not necessarily: Consider a composite material > chosen for > both rigidity and low transmission of HF energy. > Carbon > fiber, graphite fiber, high-pressure materials, vs. > undamped > metals of the same mass. Of course, "cancel" > implies an > absolute and is not the word for any of these, as > you know, > but the _relative_ transmission is varied greatly by > the > materials choice. > > But I should have more complete: I meant to tie > together the > various elements of my post on this subject and say > that > relatively LF _external_ inputs could appear at both > ends of > the record playing system (to less than an absolute > degree) > only if the intervening material was rigid at those > input > frequencies. Then, the system effectively brings a > degree > of cancellation to those inputs. OTOH, internal > chassis > movement at higher frequencies can naturally create > real > resonance to a degree dependent on the materials and > masses > involved. > > In all cases, an understanding of the source, > magnitude, and > frequencies of all energy present in the chassis is > the > prerequisite to dealing with each and every one. > Personally, I'm not too terribly concerned with > bearing > noise or motor rumble - the former is ultra-low, the > latter > is to be eliminated through adequate isolation. But > we do > have acoustic feedback and stylus energy to contend > with... > > Jon Lane > > > __________________________________________________ Do You Yahoo!? Get Yahoo! Mail – Free email you can access from anywhere! http://mail.yahoo.com/ Subject: Re: [teres] Critique my design please Date: Wed, 26 Jul 2000 00:24:14 -0700 From: ron welborne, ron welborne To: teres@aiko.com ----- Original Message ----- From: Igor Kuznetsoff To: Sent: Tuesday, July 25, 2000 11:09 PM Subject: Re: [teres] Critique my design please > > While it's probably rather apparent from the amount of > effort I've put into promoting air suspensions, > sandboxes, and various damping treatments over the > course of this project, that I am quite concerned with > dealing with externally induced vibrations, I thought > it germane to take a moment to mention that the > loudest vibration our systems will have to deal with > will actually come from the stylus banging about on > its way through the groove. Something to think about. > > Igor > I agree here, however IMO this is an issue for the cartridge/arm combination and less an issue of whether or not the arm is mounted to the same structure as the platter. An arm that utilizes proper damping material will go a long way towards reducing unwanted vibrations generated by the stylus as well as resonances within the arm tube. An arm without bearings will have less mechanical rattles due to gimble bearing clearance and cantilever resonances and thus be less susceptible to vibrations. (just my preference here) An arm that adequately compensates for cantilever excursions and groove modulation will reduce the amount of banging about....once again reducing vibrations. And finally, if the arm/cartridge subsonic resonances are heavily damped, then in conjunction with all of the above, it should be singularly non resonant (resonant free) which once again will go a long way towards damping and/or eliminating mechanical vibrations either originating from the stylus or from external sources. Ron Do You Yahoo!? ....as a matter of fact, I don't :) Subject: RE: [teres] Critique my design please Date: Wed, 26 Jul 2000 20:39:42 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > Jon, > We're finally in agreement. Maybe not entirely. The notion of sinking I fancy implies an "active" chassis of sorts, with the ability to accept and transmit rather than isolate energy, an instinct based on the assumption that this energy (referring of course to that generated by the stylus) is available for transit in the first place. Which calls the arm back into question... If my arm is like a iron rail and if playing a record is akin to striking the rail with a hammer, my goal is to find a way to entice as much of that energy _down_ the rail just as perfectly as I can, to be dumped after the fact by the most effective means I can imagine. But if I damp the portion of the rail I intend to strike with a half ton of iron welded to it, and/or another half ton of resilient wrapping or sandwiched laminations, just how effective will this before-the-fact damping be? I do not know. Striking the rail will still make a very significant sound. I currently use a Koetsu with a dense wooden body and my arm is a heavy, well damped alloy type with a tapered tube and robust bearings and a big, heavy bearing structure and mounting. How much energy appears at the big end of this definitely-not-optimized transmission line is anybody's guess. Maybe very little. But if some does, and the arm is lashed to 25 lbs of 6061 radiating out from said location with the daylights damped out of it, has one created a system more amenable to eliminating unwanted energy than would be had we attempted to utterly stop the cart body/headshell from vibrating even a little teeny bit in the first place? Your guess is as good as mine, but I do know I've yet to hear a mechanically quiet arm when influenced by our friend RIAA, and that includes nearly all materials, shapes, and masses. I'm leery of risking returning anything back to the small end that *does* escape the clutches of the headshell by mis-terminating my arm mounting. All this to say virtually nothing of the well-understood virtues of _extreme_ rigidity in the playing loop for the obvious reasons. (Ironically - and if this audio obsession holds - the next project on the boards at my house might be a dual axis, armtube-less airbearing that won't talk to the table at all anyway unless a few KHz can somehow jump the airgaps. The alum chassis will end up just being a precision mounting plate for the playing parts at that point...) > That is,indeed, why I > hope to build my minimal exposed area "Y"-shaped > chassis using a complex composite involving carbon > fiber. Stiffness & good internal loss, minimal > acoustic pickup area. I see you plan an all-composite system - arm through chassis. Presumably this method has limited ability to easily "join" stylus, headshell, arm, and chassis at the frequencies that intrigue me most. My past experience in tablemaking points to alloy paths being superior in this particular regard, should that be the intent. Although "YMMV" would be a very appropriate disclaimer to insert right about here... OTOH, the lightness and small area indicates a good immunity to external stuff. My 35lbs of milled plate will need a serious house to live in if it is to be quiet. > Also the reason why I got > rather excited about finding (reasonably priced) > off-the-shelf tapered carbon fiber tubes perfect for a > possible attempt at substituting for metal arm tubes > at: > > http://www.deltronix.com/public/acp/ACP-CAT.HTM > > With these it may be possible to take a serious shot > at the stylus energy problem, something I feel has > never been addressed properly. You mean in preventing it influencing the cart body in the first place? Doing so seems absolutely guaranteed to succeed. I'm curious how to do so... > I also have some other > rather innovative ideas about dealing with that, but > am not ready to talk about them. As to the > cancellation thing, yes, at *low* frequencies what you > describe can happen. I don't remember your specifying > low frequencies previously. (It was thought to be intuitive.) > Unfortunately, this > effect would be rather limited as the moment the > frequencies rise even a little, the transmission times > involved and the internal reflections within the > connecting materials will make such a complex > mish-mosh > of the energies present that a useful degree of > cancellation will no longer occur. You may have missed my point: At frequencies too low to induce ringing in a rigid, relatively light chassis, it cannot bend: It merely rides above external energy to a degree and is moved largely internally in phase the way a suspended chassis with arm rides as a contiguous unit immune to external LF inputs at frequencies above it's primary sprung resonance. Only at relatively high frequencies (RIAA coming back into play here...) would it presumably decouple and exhibit resonant modes. Which we'd promptly damp away. > and At that point > damping, of any material, no matter how good it is, is > necessary. There can be no disputing that > "understanding the enemy" is key to dealing with > vibrational, or any other problems. While rigid > materials with good internal damping will certainly > transmit less HF energy than undamped metal of equal > mass, just as you say, compliant ones can be expected > to transmit even less. They just aren't a good choice > for use in the manner that got us on this subject, not > having the necessary dimensional / relational > stability between arm & platter, on their own. That's correct. My concern is merely to avoid at all costs a system resonance at such a low frequency as to muddy the heart of the music at the peak of entire system's acoustic power, or in the 100+ cycle range. Once set into internal motion in these octaves, a sandwich of massive but decoupled materials (some have mused about MDF/lead/stone constructions with flexible bonds) suffers from very significant energy that possibly cannot be damped without extreme measures. Jon Lane Subject: Re: [teres] Critique my design please Date: Thu, 27 Jul 2000 08:47:52 -0700 From: Peter Boser, Peter Boser To: teres@aiko.com The Aerospace Composite products website mentioned by someone recently regarding tonearms (can't find who it was among all the "Re: Critique my design please" posts!) ( http://www.deltronix.com/public/acp/acp-cat.htm ) also has flat carbon fibre pieces at what look to me to be inexpensive prices (at least in comparison to what the Formula One racing teams claim it costs to make their cars!). Can someone with more knowledge than me (ok, everyone join in!) tell me if this stuff, or something similar available elsewhere, is the ticket for a Teres chassis? (Sorry, I'm out of parenthetical remarks ended by an exclaimation point!) Pete __________________________________________________ Do You Yahoo!? Get Yahoo! Mail - Free email you can access from anywhere! http://mail.yahoo.com/ Subject: Re: [teres] Critique my design please Date: Thu, 27 Jul 2000 10:04:49 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com That was me, Peter. I brought the site up because it is reasonably priced & carbon fiber is *definitely* of interest. There are no magic bullets, just better choices. You have to start with good materials choices, but it's what you do with them that makes the biggest difference. Carbon fiber in pre-made pieces does not need to be outrageously expensive because it is made by outfits that are well equipped to deal with it. The stuff has a reputation for being nasty to work with. I haven't tried to work with it custom yet. There is quite a difference between the cost of pre-made shapes & custom car bodies, even if they were made of just fiberglass, which is pretty much what carbon fiber/resin is worked like, I hear. I have worked with f-glass, and it's no picnic to do more than patching, believe me, especially if you try this indoors without some serious ventilation. Using pre-made flat panels, OTOH, should be no problem, pretty much like cutting a panel of fiberglass-use a dust mask(!), and figure on dulling a blade or two. No problem, if my info is correct. Definitely a nice adjunct to other materials, or try making up your own version of a Diamond Racing Platform-like chasssis, for a heck of a lot less money! Igor --- Peter Boser wrote: > The Aerospace Composite products website mentioned > by > someone recently regarding tonearms (can't find who > it > was among all the "Re: Critique my design please" > posts!) ( > http://www.deltronix.com/public/acp/acp-cat.htm ) > also > has flat carbon fibre pieces at what look to me to > be > inexpensive prices (at least in comparison to what > the > Formula One racing teams claim it costs to make > their > cars!). Can someone with more knowledge than me > (ok, > everyone join in!) tell me if this stuff, or > something > similar available elsewhere, is the ticket for a > Teres > chassis? (Sorry, I'm out of parenthetical remarks > ended by an exclaimation point!) > Pete > > > __________________________________________________ > Do You Yahoo!? > Get Yahoo! Mail - Free email you can access from > anywhere! > http://mail.yahoo.com/ __________________________________________________ Do You Yahoo!? Get Yahoo! Mail - Free email you can access from anywhere! http://mail.yahoo.com/ Subject: Re: [teres] Critique my design please Date: Thu, 27 Jul 2000 22:21:50 -0700 From: MaughanAudio@aol.com, MaughanAudio@aol.com To: teres@aiko.com In a message dated 7/26/00 1:23:13 AM Mountain Daylight Time, gorkuz@yahoo.com writes: << I have searched for small inner tubes, but the smallest I have found are nominal 12" (really ~10.5" O.D. when not stretched over a rim). These are extremely cheap (as low as $3 at K-Mart). >> Convert inner tubes to cylindrical bladders. Using the valve stem portion of the tube, just cut it to length and then seal the ends shut using tire patch cement. A clean abraded surface properly clamped and cured will give a dependable seal. Then support the bladder in some rigid cylinder such as PVC pipe shortened enough to allow the suspension to float on the air bladder. Or machine out the base for cavities to hold the air bladders. Be creative. Until again, Gordon Subject: Re: [teres] Critique my design please Date: Thu, 27 Jul 2000 22:27:41 -0700 From: MaughanAudio@aol.com, MaughanAudio@aol.com To: teres@aiko.com In a message dated 7/26/00 4:40:08 AM Mountain Daylight Time, alex_cl_lee@yahoo.com writes: << It is indeed another good alternative to just simple air bladder. Please enlighten me on the subject of combined low resonance frequency for the differences in inflated air pressure of these air casters. In a nutshell the question is how to calculate the combined tuned resonance frequency. (eg. 4 casters with 2 in 2 Hz, 1 in 3 Hz and the 4th in 3.5 Hz.) Also how do these caster with different pressure react to an excitment by a vibration. >> Once the air casters (bearings) are sealed and converted to an air bladder, the weight and dimensions of the total system will determine the resonant mode. Air pressure will compensate for leveling and tuning the resonant mode. And since these converted bladders, were originally desinged to support 500lbs per unit with only 12.5 PSI, they will easily pump up with a hand pump to support a heavy turntable assembly at a low resonant mode. But only experimenting will tell. Until again, Gordon Subject: Re: [teres] Tip Toes & Bearings Date: Sun, 30 Jul 2000 07:56:38 -0700 From: Pablo Roufogalis, Pablo Roufogalis To: teres@aiko.com At 07:23 AM 7/30/00, you wrote: >Back in January, Steve Zettel was musing about drilling and tapping a hole >in the bottom of the brass bearing journal so that the bearing could have >it's very own tip toe from which to sink energy. Hello to all. Do keep in mind that sinking and capturing are the same physical process. I would want my bearing to be as isolated as posible. There's no likely source of energy to be sunk (sank?) but there's plenty to be captured. Regards, Pablo Roufogalis L. proufo@cantv.net (se dice proufo atencion de cantevepuntonet) ˇArrobas NO!. Visite http://www.aretecnica.com/fam/od.htm Visite http://www.aretecnica.com/fampg.htm Subject: Re: [teres] Tip Toes & Bearings Date: Sun, 30 Jul 2000 13:38:50 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Pablo, Yes, this has indeed been considered. It is probably good that you have brought this up, for those who have not read the digests. This is why, early in the design process, when I wrote a number of posts promoting the use of sandboxes, I suggested the simple & inexpensively expedient use of those common foam rubber cold drink/beer can thermal jackets (the sort usually carrying some advertising or cutesy jokes), or, alternately, a simple ring of about that size, fashioned from some neoprene, or foam rubber of similar consistency to form individual pockets of sand for each cone/foot/whatever that is resting on the sand. As desired. By trimming these to a chosen size, be it just under the height of the level of the sand for cosmetic reasons, or left just higher than the sand for maximum isolation, and laying them in the box at the necessary locations prior to filling, individualized pockets of sand can be created for next to nada in cost & effort. This allows the possibility of arranging exactly the conduction paths, or not; for individualized pockets of mass for what is on them to borrow on; for separated pockets for noise sinking; or for allowing any chosen element access to the majority of the sand, entirely at your will. Can a designer of a 'table ask for more flexibility or control for so cheap?. Of course, those not using sandboxes don't get all this. Be careful about assuming that our bearings, excellent as they have been designed to be, are utopically perfect in this, our all too dystopic world…Reality always intrudes. While it is certain that the stylus will generate much more noise than the bearing will, that being my frequent concern with overly lively conduction paths between the bearing & arm, don't be so certain that the bearing has nothing whatsoever to gain from noise sinking. Keep in mind that that stylus noise also goes into the platter, then to the bearing, and then… So, what ware you going to do with that noise once it gets to the bearing? Igor P.S.- You can't be in that different a time zone! Your post is dated 7/16, (heads up), maybe your time/date setting needs resetting (or is it my mail system playing tricks again?). --- Pablo Roufogalis wrote: > At 07:23 AM 7/30/00, you wrote: > >Back in January, Steve Zettel was musing about > drilling and tapping a hole > >in the bottom of the brass bearing journal so that > the bearing could have > >it's very own tip toe from which to sink energy. > > Hello to all. > > Do keep in mind that sinking and capturing are the > same physical process. > > I would want my bearing to be as isolated as > posible. There's no likely > source of energy to be sunk (sank?) but there's > plenty to be captured. > > Regards, > > Pablo Roufogalis L. > proufo@cantv.net > (se dice proufo atencion de cantevepuntonet) > ˇArrobas NO!. Visite > http://www.aretecnica.com/fam/od.htm > Visite http://www.aretecnica.com/fampg.htm > __________________________________________________ Do You Yahoo!? Kick off your party with Yahoo! Invites. http://invites.yahoo.com/ Subject: Re: [teres] Tip Toes & Bearings Date: Sun, 30 Jul 2000 17:58:27 -0700 From: Pablo Roufogalis, Pablo Roufogalis To: teres@aiko.com At 03:35 PM 7/30/00, you wrote: > Yes, this has indeed been considered. It is >probably good that you have brought this up, for those >who have not read the digests. This is why, early in >the design process, when I wrote a number of posts >promoting the use of sandboxes, I suggested the simple >& inexpensively expedient use of those common foam >rubber cold drink/beer can thermal jackets (the sort >usually carrying some advertising or cutesy jokes), >or, alternately, a simple ring of about that size, >fashioned from some neoprene, or foam rubber of >similar consistency to form individual pockets of sand >for each cone/foot/whatever that is resting on the >sand. As desired. By trimming these to a chosen >size, be it just under the height of the level of the >sand for cosmetic reasons, or left just higher than >the sand for maximum isolation, and laying them in the >box at the necessary locations prior to filling, >individualized pockets of sand can be created for next >to nada in cost & effort. This allows the possibility >of arranging exactly the conduction paths, or not; for >individualized pockets of mass for what is on them to >borrow on; for separated pockets for noise sinking; or >for allowing any chosen element access to the majority >of the sand, entirely at your will. Can a designer of >a 'table ask for more flexibility or control for so >cheap?. Of course, those not using sandboxes don't >get all this. > Be careful about assuming that our bearings, >excellent as they have been designed to be, are >utopically perfect in this, our all too dystopic >world…Reality always intrudes. While it is certain >that the stylus will generate much more noise than the >bearing will, that being my frequent concern with >overly lively conduction paths between the bearing & >arm, don't be so certain that the bearing has nothing >whatsoever to gain from noise sinking. Keep in mind >that that stylus noise also goes into the platter, >then to the bearing, and then… So, what ware you going >to do with that noise once it gets to the bearing? What is to be gauged is the relative magnitude of platter noise vs. captured noise, i.e., will there be more noise in the platter assemby if it is isolated or if it is connected to a damping device. It would require testing to be sure. Intuitively, I'd say there very little noise produced in the bearing/platter/arm while the sound waves hitting the platter assembly and the outer/lower TT platform are several orders of magnitude higher. Perhaps what is required is not a tiptoe but a larger element. Perhaps instead of sand there could be a pool of STP where the bottom part of the platter assembly would be inmersed. My design involves a hung plater assembly and a hung damped heavy armboard assembly, the latter using a pool of STP or similar. It could be made (Ha!) to provide the same damping design for the platter assembly. At this point I believe that the armboard must be isolated completely from the TT, the platter must be isolated from the outer assembly and the outer assembly must provide acoustical isolation, i.e. a sealed cage. This design goes completely against the rigid path between platter and arm embraced by several members. This might not by itself improve the sound but if successful, would remove several variables from the design. And that is always welcome. There are still lots of variables that can be used to make it sound as you want it to. Crazy ideas to test: a platter mat with a level of sorbothane and a glass top directly in contact with the Lp. This would damp the vibrations coming up from the platter asembly but allow the Lp to resonate. Instead of glass, you could use other materials and tune them to your system and ears. Blanks for zimbals perhaps. OTOH, this could be serious overkill. The fact that no one has done it before could be a warning signal. Or maybe is good engineering but not viable for a commercial product. In my case, the outer assembly will be made of faux marble and will weight about a hundred pounds. Don't call me crazy. I was happy with my Thorens. You got me into this! Many thanks ;-) >P.S.- You can't be in that different a time zone! >Your post is dated 7/16, (heads up), maybe your >time/date setting needs resetting (or is it my mail >system playing tricks again?). Sorry. My son messed up the PC date, putting it in mid-month and Egypt time zone! Regards, Pablo the isolationist. Subject: Re: [teres] Tip Toes & Bearings Date: Sun, 30 Jul 2000 22:38:29 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Pablo, The use of oil damping baths is an excellent idea. Stick with it, my suggestion. I am planning to use oil, definitely. Much can be done with a number of variations on that theme. The use of them was discussed for the motor pods (oil+lead shot), but oil damping discussions did not extend much beyond that previously (as it was not yet time for that subject), and, of course, its use in the bearing, a slightly different topic. Oil is a superb medium for damping/absorbing vibration, and there are tricks for magnifying its efficiency in this role. I have, in the past, even used it inside a sand-filled tweet/mid satellite to damp movement (I called it a VHD-a Viscous Harmonic Damper). Worked like a charm, cost next to nothing to speak of. And yes, all even remotely relevant discussion is welcome. Plus, this time you really hit on a good topic, run with it! Igor ------------------snip--------------- > >Keep in mind > >that that stylus noise also goes into the platter, > >then to the bearing, and then… So, what are you > >going > >to do with that noise once it gets to the bearing? > > > What is to be gauged is the relative magnitude of > platter noise vs. > captured noise, i.e., will there be more noise in > the platter assemby if it > is isolated or if it is connected to a damping > device. > > It would require testing to be sure. Intuitively, > I'd say there very > little noise produced in the bearing/platter/arm > while the sound waves > hitting the platter assembly and the outer/lower TT > platform are several > orders of magnitude higher. > > Perhaps what is required is not a tiptoe but a > larger element. Perhaps > instead of sand there could be a pool of STP where > the bottom part of the > platter assembly would be inmersed. > > My design involves a hung plater assembly and a hung > damped heavy armboard > assembly, the latter using a pool of STP or similar. > It could be made (Ha!) > to provide the same damping design for the platter > assembly. > > At this point I believe that the armboard must be > isolated completely from > the TT, the platter must be isolated from the outer > assembly and the outer > assembly must provide acoustical isolation, i.e. a > sealed cage. > > This design goes completely against the rigid path > between platter and arm > embraced by several members. > > This might not by itself improve the sound but if > successful, would remove > several variables from the design. And that is > always welcome. There are > still lots of variables that can be used to make it > sound as you want it to. > > Crazy ideas to test: a platter mat with a level of > sorbothane and a glass > top directly in contact with the Lp. This would damp > the vibrations coming > up from the platter asembly but allow the Lp to > resonate. > > Instead of glass, you could use other materials and > tune them to your > system and ears. Blanks for zimbals perhaps. > > OTOH, this could be serious overkill. The fact that > no one has done it > before could be a warning signal. Or maybe is good > engineering but not > viable for a commercial product. In my case, the > outer assembly will be > made of faux marble and will weight about a hundred > pounds. > > Don't call me crazy. I was happy with my Thorens. > You got me into > this! Many thanks ;-) > > > >P.S.- You can't be in that different a time zone! > >Your post is dated 7/16, (heads up), maybe your > >time/date setting needs resetting (or is it my mail > >system playing tricks again?). > > Sorry. My son messed up the PC date, putting it in > mid-month and Egypt time > zone! I only noticed after accidentally deleting, even as I realized that this was actually a good topic, and should be discussed. It then took a while to work back through my slow-as-molasses during busy periods system to retrieve it, pointing out the date. > > Regards, > > Pablo the isolationist. > > __________________________________________________ Do You Yahoo!? Kick off your party with Yahoo! Invites. http://invites.yahoo.com/ Subject: RE: [teres] Critique my design please/And beyond... Date: Mon, 31 Jul 2000 00:45:06 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com --- Jon Lane wrote: > > Jon, > > We're finally in agreement. > > Maybe not entirely. Well, I suppose, that it was too much expect *complete* agreement, but it did seem like there may have been some general progress … > The notion of sinking I fancy > implies > an "active" chassis of sorts, with the ability to > accept and > transmit rather than isolate energy, an instinct > based on > the assumption that this energy (referring of course > to that > generated by the stylus) is available for transit in > the > first place. Which calls the arm back into > question... Ahh! Well then, you *are* moving towards (some) agreement! This can't be a bad thing. The trick is to realize that it is possible, to some, if rather imperfect degree, to direct & absorb (as in damp down in level) this energy, before it can reflect back to the stylus, or do damage via some other path. And I believe it *is* possible to create, to an extent, a fairly "active" chassis, if in a "preferentially passive" way. By this I do not mean some sort of active noise canceling system, with sensors, amplifiers inverters, or any such impracticalities. What I do mean is that it should be possible to create paths of least resistance leading to means of absorbing the noise, while arranging other necessary links (yes, yes, *rigid*, just less conductive) to resist, or, at least, not so enthusiastically support, that conduction. Like convincing a stream to go along the channels you've arranged, and not where it will, wildly. It will still soak the ground it travels, but, if we can get it to go our way, it at least won't pool where we need a dry area. And yes, the arm is the most difficult area to deal with, we appear to have some agreement on that. > > If my arm is like a iron rail and if playing a > record is > akin to striking the rail with a hammer, my goal is > to find > a way to entice as much of that energy _down_ the > rail just > as perfectly as I can, to be dumped after the fact > by the > most effective means I can imagine. Yes, we appear to be in agreement on that. >But if I damp > the > portion of the rail I intend to strike with a half > ton of > iron welded to it, and/or another half ton of > resilient > wrapping or sandwiched laminations, just how > effective will > this before-the-fact damping be? I do not know. > Striking > the rail will still make a very significant sound. Still no apparent disagreement. A noise of some sort will still be made, and applying treatments at, or near, the headshell has mass penalties. I have been able to apply some, with good effect, carefully, but this is very limited. Worse, the arm system is a complicated device, and hardly forms an ideal transmission line, what with all of its intricate parts. Further, with the exception of unipivots (which, due to their particular layout, work under a good number of pounds per square inch at the pivot, offering a better conduction path than most other systems), the majority of arms don't even pass the noise very well past their bearings. > > I currently use a Koetsu with a dense wooden body > and my arm > is a heavy, well damped alloy type with a tapered > tube and > robust bearings and a big, heavy bearing structure > and > mounting. Apparently good choices vis-a-vis this line of reasoning. I certainly agree with the use of tapered tubes, and tend to wince every time I *don't* see one. How much energy appears at the big end of > this > definitely-not-optimized transmission line is > anybody's > guess. Maybe very little. That may be an optimism. Let's say less than many others, anyway? But if some does, and > the arm is > lashed to 25 lbs of 6061 radiating out from said > location > with the daylights damped out of it, has one created > a > system more amenable to eliminating unwanted energy > than > would be had we attempted to utterly stop the cart > body/headshell from vibrating even a little teeny > bit in the > first place? Your guess is as good as mine, but I > do know > I've yet to hear a mechanically quiet arm when > influenced by > our friend RIAA, and that includes nearly all > materials, > shapes, and masses. I'm leery of risking returning > anything > back to the small end that *does* escape the > clutches of the > headshell by mis-terminating my arm mounting. Agreed, as well, where the RIAA is concerned. I suspect that the process of getting the noise past & out of the arm system runs into serious problems, though. And, then, comes the problem of dealing with the elimination of that energy. There are many possible approaches to accomplishing this, but that is where the agreement joyride ends. I have previously brought up the unfortunate nature of large chunks of metal toward acting more as reverberation tanks than the means of killing that energy. But, have at it your way. In *your* system. I sure don't expect to find reason to agree on that item. If, at least, you were to *thin* out the thickness of these, and just use the ability of metal to conduct the noise to where it can be dispensed with, I think it would work better. More like Ivan Anderson's (IIRC) idea of using blades in sand, as opposed to chunks of metal. > > All this to say virtually nothing of the > well-understood > virtues of _extreme_ rigidity in the playing loop > for the > obvious reasons. (Ironically - and if this audio > obsession > holds - the next project on the boards at my house > might be > a dual axis, armtube-less airbearing that won't talk > to the > table at all anyway unless a few KHz can somehow > jump the > airgaps. The alum chassis will end up just being a > precision mounting plate for the playing parts at > that > point...) At least we clearly don't disagree about rigidity. This is nice. Not knowing more about the visualization of your "armless" pickup system, there is no more appropriate comment to make other than to wish you success with it, and offer a bit of advice. Just don't forget about Newton. The arm tube is part of the reaction mass system. To do without its opposition, and still get complete compliance with large excursions (presumably mostly at lower frequencies), you will need a fair amount of mass (relatively speaking) at the headshell, and/or an outrageously compliant cartridge. It may then be difficult to get this to track warps well, and I don't necessarily mean big ones, either. > > > That is,indeed, why I > > hope to build my minimal exposed area "Y"-shaped > > chassis using a complex composite involving carbon > > fiber. Stiffness & good internal loss, minimal > > acoustic pickup area. > > I see you plan an all-composite system - arm through > chassis. "Maybe not entirely", to quote. But, that is quite understandable. Due to previous events, I declined to describe my plans too completely. And will continue to keep some details close to vest. I will, to follow up my statement from above, mention that this is not so. Pursuant to that statement, it should be pointed out that I *do* intent to use metal, *carefully* to provide *intended* conduction paths from the arm to sand, and from bearing to sand, plus some tricks. Actually, I have already intimated this previously, when I wrote that I consider it to be more important to match the material of the part one desires to sink noise from for impedance matching, than it is to simply make a single materials choice. The cone under the bearing will therefore be brass, and, ostensibly, the one under the arm will be aluminum. Plus some tricks, if I can find my way to affording the machining I have in mind. Simpler tricks, if not. The bearing had originally been planned to have a hole pre-drilled & ready for tapping, on Steve Z's excellent suggestion. Regrettably, I discovered, upon receipt of my platter/bearing set, that this was not done, and no mention of that deletion was made previously, surprising me a bit. Unfortunately, I do not have my own drill press. Still, this is not all that difficult to do, and well worth doing in a system that can take advantage of this. Presumably this method has limited ability > to > easily "join" stylus, headshell, arm, and chassis at > the > frequencies that intrigue me most. My past > experience in > tablemaking points to alloy paths being superior in > this > particular regard, should that be the intent. > Although > "YMMV" would be a very appropriate disclaimer to > insert > right about here... Here we differ, as well. I endeavor to do all I can to *prevent* the vibrational hookup of the arm system & platter system, preferring to sink the noise, instead, via more controllable paths, away from these. So these noises can't repeat through looping. Which is to say that, actually, we agree-that I do not wish to join these, although the headshell, & arm system will be joined. Just not to, or I should really say, *through*, the chassis. > > OTOH, the lightness and small area indicates a good > immunity > to external stuff. My 35lbs of milled plate will > need a > serious house to live in if it is to be quiet. Uhuh. In my case, the mass of the sandbox will provide that quiet for my chassis, after decoupling from the rest of the room via a two stage air suspension, that with the mass (also sand-filled/albeit to a different weight) of the stand in between the two pneumatic sections. Tuned to, if all works to plan, different passbands, to effect a net of "zero passband", from the floor. > > > Also the reason why I got > > rather excited about finding (reasonably priced) > > off-the-shelf tapered carbon fiber tubes perfect > for a > > possible attempt at substituting for metal arm > tubes > > at: > > > > http://www.deltronix.com/public/acp/ACP-CAT.HTM > > > > With these it may be possible to take a serious > shot > > at the stylus energy problem, something I feel has > > never been addressed properly. > > You mean in preventing it influencing the cart body > in the > first place? Doing so seems absolutely guaranteed > to > succeed. I'm curious how to do so... Actually, no, or not exactly... I have it in mind that it will provide the necessary rigidity without transmitting, and, more importantly, *reflecting back* the energy as eagerly as metal does. The reflecting back aspect should be obvious enough. Lest the transmitting aspect be misunderstood, in terms of moving the energy away from the cart, it should be said I don't believe that this means that it won't, but, rather, that it will do double duty along the way by damping it down as it travels, and that can't be a bad thing. But… I don't know this yet. Note the use, above, of the word "possible". This is only what I expect of it. And I have other ideas in mind, additionally. If one doesn't try new tricks, one accomplishes no discoveries. I know that I will find no new lands by treading the well-worn trails. All of this is extremely ambitious, and beyond my immediate resources. It is almost certain that my 'table will be very long in being realized. I will be watching everyone's efforts jealously, and slowly grinding my way forward, detail by detail. But, then, I didn't wait all those years for the sort of opportunity this project offers to dash off a half-baked shadow of all that I have envisioned. > > > I also have some other > > rather innovative ideas about dealing with that, > but > > am not ready to talk about them. As to the > > cancellation thing, yes, at *low* frequencies what > you > > describe can happen. I don't remember your > specifying > > low frequencies previously. > > (It was thought to be intuitive.) I'm sure you have heard the common exposition of the word "assume". As, umm, *thoroughly* as you tend to discourse, it would be wise not to skip over the foundation points of your sometimes exotic theorizing. > > > Unfortunately, this > > effect would be rather limited as the moment the > > frequencies rise even a little, the transmission > times > > involved and the internal reflections within the > > connecting materials will make such a complex > > mish-mosh > > of the energies present that a useful degree of > > cancellation will no longer occur. > > You may have missed my point: Weeeeell…. No. This is one of the basic theories behind earthquake proofing, as a matter of fact, to throw in a touch of trivia. But, to consider that point, I would have needed to know that you were *only* speaking of VLF (which whales & elephants use to communicate over long distances, but this didn't cue me in, either). At frequencies too > low to > induce ringing in a rigid, relatively light chassis, > it > cannot bend: It merely rides above external energy > to a > degree and is moved largely internally in phase the > way a > suspended chassis with arm rides as a contiguous > unit immune > to external LF inputs at frequencies above it's > primary > sprung resonance. Only at relatively high > frequencies (RIAA > coming back into play here...) would it presumably > decouple > and exhibit resonant modes. Which we'd promptly > damp away. > > > and At that point > > damping, of any material, no matter how good it > is, is > > necessary. There can be no disputing that > > "understanding the enemy" is key to dealing with > > vibrational, or any other problems. While rigid > > materials with good internal damping will > certainly > > transmit less HF energy than undamped metal of > equal > > mass, just as you say, compliant ones can be > expected > > to transmit even less. They just aren't a good > choice > > for use in the manner that got us on this subject, > not > > having the necessary dimensional / relational > > stability between arm & platter, on their own. > > That's correct. My concern is merely to avoid at > all costs > a system resonance at such a low frequency as to > muddy the > heart of the music at the peak of entire system's > acoustic > power, or in the 100+ cycle range. Once set into > internal motion in these octaves, a sandwich of >massive but decoupled materials (some have mused >about MDF/lead/stone constructions with flexible >bonds) suffers from very significant energy that >possibly cannot be damped without extreme measures. > And I agree that this is a legitimate concern. This is not only, as you say, the heart of the music, but also the peak area on the bell curve of acoustical power distribution, making it all the more problematical of an area. This was one of my thoughts with respect to a light chassis being above that area in resonance (and damped to kill those easier-to-damp higher frequencies, as well), and the massive, internally well damped sandbox being well below. Couple the two together, and… You see where I am heading? The whale and the canary sing few songs together. It is good to end on a note of agreement……I hope. Igor __________________________________________________ Do You Yahoo!? Kick off your party with Yahoo! Invites. http://invites.yahoo.com/ Subject: [teres] Critique my design Date: Mon, 31 Jul 2000 17:14:09 -0700 From: Pablo Roufogalis, Pablo Roufogalis To: teres@aiko.com At 02:16 AM 7/31/00, you wrote: >Pablo, TNX for your post. I hope you could further discuss this. Hello to all. I will send drawings when I find the peace of mind to do them. Don't expect anything fancy like CAD. MacDraw or Canvas in an Acrobat file tops. Perhaps I can describe it so you can adapt for your own and also provide comments now. Sorry if it's convoluted. The outer assembly of the TT is U-shaped, looked from above. Will be made of faux-marble using common (I've been told) techniques from sculptors. It's a casting that will be machined and polished. The platter assembly is made of steel or aluminium. It is star-shaped and 4 points of the star have fishing lines to hang them from the outer assembly (adjustable for height with screws). The center of the star has an assembly for the bearing, perhaps a cup (separate piece, rigidly fixed) or similar filled with a castable rigid compound. There could be a large dish-shaped piece in the bottom side of the platter assembly that would be submerged in a second STP bath for additional damping. The fifth point of the star rigidly holds a cup- or drinking glass-shaped reservoir which will be filled with STP or perhaps a more viscous material. Three additional star points balance the fifth with adjustable weights or perhaps with cups to be filled with sand and lead. The arm is fixed to a small platform that is tied to the rim of the cup with very short fishing lines. The platform itself is rigidly fixed to a heavy piece that is submerged in the STP. I visualize it as a lead cilinder. The platform weight, the strings and the STP will allow the arm not to move in relation to the platter but also allow for the paths to any other TT component to be not-rigid. Any vibration through the fishing lines would be damped by the STP bath. This is a key assumption which may have to be tested. This design is an area where I believe improvements could be made. My SME arm must be modified in order to connect the leads from above. Doesn't look difficult or risky. The dust cover (acrylic) would hinge from the top of the U and would get inserted in a deep-enough groove that would seal the inside of the TT from the outside world. There would be one or two lips in the groove to guarantee a good seal or perhaps the groove could be filled with a flowing plastic so the dust cover would fit itself perfectly, with some silicone for lubrication. The bottom end of the U assembly (a hole about the size of the platter) will also be covered with a disc-shaped piece that would seal the bottom. Contact with the supporting table or stand will be made with two or more concentric strips of thin rubber. The motor will be affixed to a plate in the top of the U. There could be some pulling of the platter assembly when the motor runs. Movement of the assembly will probably be negligible due to its weight and if it is damped even less so. If necessary, the supporting strings opposite to the motor might pull at an angle to compensate. There will be wire mesh embedded in the U shell and in the dust cover to create a Faraday box for further elimination of external factors such as EMI. Hope the dust cover won't look too crazy. One concern with STP would be oil vapors, more so if there's no air path outside. Cooking the STP for an hour or so in the BBQ outside (please not indoors) might remove all light components so there would be no significant amount of fumes inside of Teres. All this is absolutely theoretical and I'm not in the first Teres platter batch so it will take a while for me to start this project. But I might try with a Thorens platter first and later rework for Teres. Then I will find the practical construction limitations to this design. At this point I believe everything above is feasible. The design concept is to diminish several factors that might affect sound. It won't by itself provide good sound so the remaining elements must still be selected and matched. Fire away. Hope it's useful. Looking forward to any and all the input you want to provide. Many thanks in advance and regards, Pablo Roufogalis L. proufo@cantv.net (se dice proufo atencion de cantevepuntonet) ˇArrobas NO!. Visite http://www.aretecnica.com/fam/od.htm Visite http://www.aretecnica.com/fampg.htm Subject: [teres] Teres progress report Date: Mon, 14 Aug 2000 09:10:20 -0700 From: David Suess, David Suess To: teres@aiko.com It's not "alive" yet, but over this past weekend, I completed the table portion of my Teres project. My design is very simple, a knockoff of Chris', but substituting .5" Corian for his aluminum. The base is further damped by being bolted to two layers of .75" MDF. The Corian is basically white flecked with gray and black, so I painted the MDF black. It's not bad looking, but I plan on re-doing the MDF layers when I can get access to a table saw. Cutting MDF with a hand held jigsaw does not make for accurate cuts, even with a guide clamped to the MDF sheet. The bearing filling process was a PITA. I fiddled with it for at least 30 minutes, finally getting it to be about 1" from being fully seated without the platter. Installing the platter pushed it down further and leaving it overnight brought it down more. By the time I get home from work, it should be fully seated. I think part of the problem was that my air-conditioned listening room in the basement makes for an even tighter fit for the bearing. I am using glycerin for bearing oil. Giving the platter a spin, I too was mesmerized just watching it spin and spin and spin... Later this week I'll probably take the RB300 from my Planar 3 table and install it on the Teres. Waiting for the motor/controller delivery... - david Subject: Re: [teres] Teres progress report Date: Mon, 14 Aug 2000 15:08:45 -0700 From: Pablo Roufogalis, Pablo Roufogalis To: teres@aiko.com At 11:09 AM 8/14/00, you wrote: >. I am using glycerin for bearing oil. Giving >the platter a spin, I too was mesmerized just watching it spin and spin >and spin... Dear David, Hello. Conventional thinking in lubrication says that glycerin is only adequate for drawing metals due to its high fatty-compounds content and for its tackiness. I believe that it may also oxidize rapidly and gums would tend to form -though they might be sheared by the bearing. I don't believe there's any factor that would make glycerin better that regular mineral oil for this application. BTW, unless you have a second TT, don't remove the arm until Teres is completely set up. You don't want to be TT-less. I am living that and it's unbearable :-) Regards, Pablo Roufogalis L. proufo@cantv.net (se dice proufo atencion de cantevepuntonet) ˇArrobas NO!. Visite http://www.aretecnica.com/fam/od.htm Visite http://www.aretecnica.com/fampg.htm Subject: Re: [teres] Teres progress report Date: Mon, 14 Aug 2000 15:17:07 -0700 From: phclark, phclark To: teres@aiko.com Pablo, If memory serves, your recommendation is mineral oil for this application? Garden variety drug store stuff? I just mounted the platter and am kind of anxious to watch it go round and round and round and round... Peter C ----- Original Message ----- From: "Pablo Roufogalis" To: Sent: Monday, August 14, 2000 2:01 PM Subject: Re: [teres] Teres progress report > At 11:09 AM 8/14/00, you wrote: > >. I am using glycerin for bearing oil. Giving > >the platter a spin, I too was mesmerized just watching it spin and spin > >and spin... > > Dear David, > > Hello. Conventional thinking in lubrication says that glycerin is only > adequate for drawing metals due to its high fatty-compounds content and for > its tackiness. > > I believe that it may also oxidize rapidly and gums would tend to form > -though they might be sheared by the bearing. > > I don't believe there's any factor that would make glycerin better that > regular mineral oil for this application. > > BTW, unless you have a second TT, don't remove the arm until Teres is > completely set up. You don't want to be TT-less. I am living that and it's > unbearable :-) > > Regards, > > Pablo Roufogalis L. > proufo@cantv.net > (se dice proufo atencion de cantevepuntonet) > ˇArrobas NO!. Visite http://www.aretecnica.com/fam/od.htm > Visite http://www.aretecnica.com/fampg.htm > > Subject: Re: [teres] Teres progress report Date: Mon, 14 Aug 2000 16:16:57 -0700 From: David Suess, David Suess To: teres@aiko.com Pablo noted: > Hello. Conventional thinking in lubrication says that glycerin is only > adequate for drawing metals due to its high fatty-compounds content and for > its tackiness. > > I believe that it may also oxidize rapidly and gums would tend to form > -though they might be sheared by the bearing. Well, in my haste to be one of the first to get a report out on my Teres project, I said glycerin when I really meant mineral oil. And to answer Mr. clark's question, it's plain old drug store mineral oil. > BTW, unless you have a second TT, don't remove the arm until Teres is > completely set up. You don't want to be TT-less. I am living that and it's > unbearable :-) Yeah, I hear you... But then I don't do a lot of vinyl listening in the summer - too many other things going on. I usaully do much more other times of the year since my wife tends to have a lot more evening work-related meetings then. Anyway, I just want to mount the arm on my Teres and see if I need further tweaks on the setup, etc. And to take a few pics to send to the list ;-) - david Subject: Re: [teres] Teres progress report Date: Mon, 14 Aug 2000 16:44:37 -0700 From: Pablo Roufogalis, Pablo Roufogalis To: teres@aiko.com At 05:16 PM 8/14/00, you wrote: >If memory serves, your recommendation is mineral oil for this application? >Garden variety drug store stuff? I just mounted the platter and am kind of >anxious to watch it go round and round and round and round... Dear Peter, Hope that "mounted the platter" does not mean "dry". The finishing is so good it would be a waste to create microscopic damage. The natural recommendation is what is called hydraulic oil. Quoting from a previous posting: Oils of all kind typically have mineral oils (petroleum destillates) and chemical additives. Synthetic oils are made of chemical compounds that act both as oil and as chemicals. Synths are made mostly for specific applications, non-flammable fluids, high temperature applications and the such. Lubes like Mobil 1 are of very high quality and high price but their effectiveness is similar to several changes of conventional oils. For our application synthetics are not needed and probably not recommended. For applications such as a bearing, the typical formulation is a mineral oil with a small amount of rust and oxidation, and antiwear additives. These are used frequenty in hydraulic systems. The Exxon brand for them is Nuto H. Nuto H of very low viscosities are available, from ISO 5 up. Another option is one with no antiwear additives. They are called industrial oils. The Exxon brand for then is Teresso. The minimum viscosity for them is ISO 32 (AFAIK). Both should be readily available anywhere, but the minimum container is probably a gallon or even more. They are very cheap though. An industrial provider (brick and mortar) might be willing to give you samples if you ask kindly enough. Equivalents from other producers do exist and sellers are able to tell you which ones are the same as the Exxon ones above. I will use a local equivalent of Nuto H ISO 22 grade when the time comes to it. Lower viscosities are not readily available here in the tropics. If I can find a good enough reason I might test lower viscosities later. CAUTION FOR TESTERS: The mix of detergent engine oils (all crankase oils) with the lubricants above might create large aggregates of chemicals which are undesired. Detergentes and most of the chemicals in crancase oils are totally unneeded for our application. End of quote. Additional info: Molybdenum disulfide in powdered form rubbed with a rag in the bearing surfaces might be a nice overkill. Ditto for a colloidal graphite enriched lubricant (see below). Moly in oil or graphite in powder form are not the better alternatives. Another quote: I found a candidate. It is an ISO 22 meeting MIL-L-3572A. To give you an idea, it is similar in viscosity to a grade 5W engine oil. Due to the graphite, it is black. Very distinctive. Manufacturer is: Convoy Oil Philadelphia 1412 N. Front St. P.O. Box 29336 Philadelphia, PA 19125 Phone: (215) 739-5281 Fax: (215) 739-6933 I'd guess if someone geographically close kindly requests a one-quart sample for distribution it would last forever. End of quote. There are probably many suppliers. Convoy was easy to find using an Internet search engine. I'd use an oil meeting MIL-L-3572A if I could find it. But I wouldn't lose sleep if I had to use a plain hydraulic oil. Regards, Pablo Roufogalis L. proufo@cantv.net (se dice proufo atencion de cantevepuntonet) ˇArrobas NO!. Visite http://www.aretecnica.com/fam/od.htm Visite http://www.aretecnica.com/fampg.htm Subject: RE: [teres] Breaking News, folks... Date: Mon, 4 Sep 2000 09:28:17 -0700 From: Paul Croft, Paul Croft To: teres@aiko.com Hi Thom, Gosh, you sound as rabid about biking as I am about sea kayaking. I have to admit, this turntable has been distracting me! Actually, I will be using an MDF arm board for now. You did give me the idea of how to implement the darned thing. Thanks! Thom, if you fill the arm board with shot and mineral oil, won't this in effect be decoupling the arm from the platter. I would think that one would want the tonearm mounted on as similar material to the material the platter bearing is mounted on, as possible. Then, hopefully, the platter and tonearm will vibrate together. For instance, at this point, my platter bearing will be mounted on a piece of MDF. The arm board will be made out of MDF and bolted to this same piece. I think that using bolts, as opposed to glue, will more tightly couple the arm to the platter. At this point I can suspend or do whatever I want beneath the main piece of MDF (that both platter bearing and arm board are mounted to) and it will affect the platter and tonearm equally. You know, I'm just thinking out loud here. If I'm way off base, would someone be so kind as to clue me in? :>) By the way, is what the platter bearing is mounted on called the plinth? If not, what the heck is the plinth? I never have quite figured out the terminology here. Well, for today's trick, I'm going to start lining up my tone-arm to mount it. I have never done this before so, it should be interesting. I think I've armed myself with enough facts and figures from this list and the WWW to at least have an idea. I've ordered a pair of MC step-up transformers from Pers Lundhal. Hopefully, these will arrive this week and allow me to wire in my $25.00 cheapy preamp from Triode Electronics. Then I can listen to some tunes while I build a real phono stage! Well, I guess I'd better get going. I've noticed this turntable refuses to build itself. Worse than a durned cat! (Well, look who's sleeping next to me as I write. Surprise, surprise, it's Dan the Cat! What a life.) Cheers, Paul > -----Original Message----- > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > Thom Mackris / Joan Panzella > Sent: Monday, September 04, 2000 12:37 AM snip... I was contemplating a circular base with an extension to mount the armboard to. Perhaps rectangular is more > effective however. On one hand, I can see the benefits of less surface > area/vibration modes, OTOH, a larger base would have more volume for lead > shot & mineral oil. > snip... > > Cheers, > Thom Subject: Re: [teres] Breaking News, folks... Date: Mon, 4 Sep 2000 22:58:43 -0700 From: Thom Mackris / Joan Panzella, Thom Mackris / Joan Panzella To: teres@aiko.com Nuts ... yeah, I need to figure out how to retire at 49 (good luck - I have 4 months left before I turn 50!) so I can have time for all of my interests, and *maybe* even do some good deeds on this planet. It's difficult to figure out how to balance a marriage, hi-fi, bicycling, running, rock climbing (which I seem to have either too little time or too little nerve for anymore) along with WORK! And that's only during the warm months! Regarding the armboard, I didn't mean to communicate that I was going to do the mineral oil & shot in it also, although I had been considering it. Perhaps this is why that message bled through in my writing. The problem as I see it is that there wouldn't be much room for a cavity sufficient to accomplish much damping. Additionally, it might end up compromising rigidity more than it helps damping. I figure that all I'd have room for is perhaps a one inch diameter hole. Keeping in mind that acrylic part of the armboard is only 1/2" thick, I don't think I'd accomplish too much. Most likely, I'll stick with a solid sandwich of aluminum / acrylic / aluminum. The usage of plinth has confused me somewhat too & as a result, I've waffled in my own usage of the term. I think that what we're building is a base. I've always heard the term plinth used with respect to suspended turntables. The plinth is the outer shell & top surface - in other words, what you normally see on a Linn, Merrill, AR, etc. The subchassis (to which the armboard is affixed) is suspended via springs from this plinth. Flash! I just looked plinth up in Websters http://www.m-w.com/cgi-bin/dictionary ), and technically I suppose we can call our bases plinths too! Oh well ... Main Entry: plinth Pronunciation: 'plin(t)th Function: noun Etymology: Latin plinthus, from Greek plinthos Date: 1601 1 a : the lowest member of a base : SUBBASE b : a block upon which the moldings of an architrave or trim are stopped at the bottom 2 : a usually square block serving as a base; broadly : any of various bases or lower parts -- see BASE illustration 3 : a course of stones forming a continuous foundation or base course This explains why I've seen the term used for the bases underneath some speakers. The beauty of the rotating (single point attachment) armboard, a la Verdier is that your drilling location doesn't have to be nearly as precise. A slight rotation and you get to dial in your exact overhang. You never have to mess around with your cartridge screws once you've anchored them down. I had been wrestling with the armboard concept for quite a while (I *really* bugged Chris about this). In addition to all of the normal requirements of rigidity, tight coupling, etc., I wanted a setup in which there was (a) easy access to the underside of the arm (for several reasons including for Rega owners - to have easy access to the nut if this is required for their chosen means of VTA adjustment) along with (b) at least a couple of inches of clearance underneath so that arm cables could make a graceful bend. The ease of adjusting overhang via rotating the armboard was an added bonus in this design and appears to come at absolutely no cost, as long as you use a big honkin' bolt to attach it to the chassis (plinth? ). BTW, you'll note that Steve Zettel's figures for the Rega are validated on the Analog Addicts Linn FAQ's which I had referenced quite a while back. These FAQ's keep popping up everywhere & I noticed them appearing in that Chicago Audio Society link I forwarded to the list yesterday. When I say validated, I'm going from a starting point of 222 mm pivot to spindle distance which Steve quoted. Their chart specifies 8.76" which converts to 222.5 mm (close enuf!). For this length, it specifies between 18 and 18.1mm of overhang - exactly what Steve quoted. Regarding Lundahl, in addition to Manfred's and Lynn Olson's glowing testimonials about this iron, Gizmo just went on a rant (when doesn't he?) about Lundahl iron in the current issue of the Listener - a 300B with a 2A3 driver and some new VAIC as an input tube ... all Lundahl iron, plate chokes, IT coupled, etc. etc. Some fellow in North Carolina contacted Per Lundahl and suggested a showcase project for his iron. I haven't had the time to check out Gizmo's site in quite a while (ever since he split from Steve Rochlin's site). There seemed to be very few links on the new site ( http://www.meta-gizmo.com/ ). It was right in front of my nose, and perhaps I didn't look too hard because all of the obvious text had no links associated with them. Additionally, I recall receiving an e-mail stating that most of his intellectual property was trashed during his scuffel with Steve R. Anyway, all of his articles are under the TRIODE GUILD link. In the "Dancing on the Edge" heading is the "Lundahalarama-Cool Iron" link. Since I just found it last night, I haven't been through it & I don't know if there's much useful information there. Right above this link, you'll find the information about Myron Toback (silver supplier) that Bob C. forwarded to the list recently. Funny, but I've noticed that my 'table has not built itself either ( The bright side of this I suppose is a pearl of Ken's "what good would it be if your hi-fi was done?". He might have a point - there'd be nothing left to do. Cheers, Thom ----- Original Message ----- From: Paul Croft To: Sent: Monday, September 04, 2000 9:27 AM Subject: RE: [teres] Breaking News, folks... Hi Thom, Gosh, you sound as rabid about biking as I am about sea kayaking. I have to admit, this turntable has been distracting me! Actually, I will be using an MDF arm board for now. You did give me the idea of how to implement the darned thing. Thanks! Thom, if you fill the arm board with shot and mineral oil, won't this in effect be decoupling the arm from the platter. I would think that one would want the tonearm mounted on as similar material to the material the platter bearing is mounted on, as possible. Then, hopefully, the platter and tonearm will vibrate together. For instance, at this point, my platter bearing will be mounted on a piece of MDF. The arm board will be made out of MDF and bolted to this same piece. I think that using bolts, as opposed to glue, will more tightly couple the arm to the platter. At this point I can suspend or do whatever I want beneath the main piece of MDF (that both platter bearing and arm board are mounted to) and it will affect the platter and tonearm equally. You know, I'm just thinking out loud here. If I'm way off base, would someone be so kind as to clue me in? :>) By the way, is what the platter bearing is mounted on called the plinth? If not, what the heck is the plinth? I never have quite figured out the terminology here. Well, for today's trick, I'm going to start lining up my tone-arm to mount it. I have never done this before so, it should be interesting. I think I've armed myself with enough facts and figures from this list and the WWW to at least have an idea. I've ordered a pair of MC step-up transformers from Pers Lundhal. Hopefully, these will arrive this week and allow me to wire in my $25.00 cheapy preamp from Triode Electronics. Then I can listen to some tunes while I build a real phono stage! Well, I guess I'd better get going. I've noticed this turntable refuses to build itself. Worse than a durned cat! (Well, look who's sleeping next to me as I write. Surprise, surprise, it's Dan the Cat! What a life.) Cheers, Paul Subject: [teres] Granite good/no good? Date: Tue, 5 Sep 2000 09:44:04 -0700 From: Thom Mackris, Thom Mackris To: Thom Mackris (h) Originally posted to the Joe List ----- Original Message ----- From: Thom Mackris To: Joe List Sent: Saturday, September 02, 2000 5:19 PM Subject: Re: [JN] Granite good/no good? Richard, Steffen, We've been kicking around some chassis/base ideas on the Teres turntable list for a while now. There have been two camps at "war" with each other (not really war, but the discussion did get enthusiastic for a while - remember the cathode follower thread on this list, a while back?) Anyhow, the two camps are the lossy camp vs. the rigid camp. Of course, as any dialog evolves, the camps are moving together (to a great extent) to a damped *and* rigid design. Jon Lane contributed much to this dialog. His comments, in conjunction with the implementation of the Scheu 'table (which was the inspiration for the Teres) which uses a stainless steel base have shifted the focus in this project considerably. Fellow perpetrator of this project (Chris Brady) has an interesting design which still isn't fully implemented. Check out the Teres DIY Turntable link for photos, diagrams, etc. There are instructions for subscribing to the list (graciously hosted by Roscoe, BTW) if you're interested. Action is a bit slow at the moment - the current dialog centers on assembling Manfred's outrageously good motor controller design (thanks, Manfred!), but I suspect in the next month or so, the dialog will return to bases and stands as people realize that these parts are missing http://reality.sgi.com/cbrady_denver/audio/ I'm thinking of a slightly different design from Chris'. There are no drawings of these thoughts on the web site yet, but it's fairly simple. The base will be a sandwich of: 3/16" aluminum - 2" acrylic - 3/16" aluminum (pick your shape). There will be cavities in the acrylic into which I will place lead shot and mineral oil for damping. The armboard will be an oval affair, with a similar aluminum / acrylic / aluminum sandwich except that the acrylic will only be 1/2" thick, yielding an armboard thickness of 7/8". The armboard will bolt onto the chassis at one point, much like the Verdier's armboard does. I like this arrangement as long as there's a substantial bolt holding it in place, because you can adjust cartridge overhang by rotating the armboard. I really think there's something going on with these super decks being unsuspended. Of course, now you also have to start thinkng of a stand for your 'table to sit on. Do *not* neglect this aspect of the design ... it is key to your success! Cheers, Thom Subject: [teres] Wow, the fat lady sings! Date: Wed, 6 Sep 2000 07:41:15 -0700 From: Paul Croft, Paul Croft To: Teres Hi folks, Well, I got my tone arm mounted last night. Put the fishing string back on and listened to my twenty year old copy of J.J. Cale's "Naturally" By golly, even without tuning, this one is better than the CD! Seriously, this Teres sounds pretty darned good just starting out. The Denon DL-103 cartridge does have some breaking in to do. The music is a little recessed and distant. After two hours of listening though, this is already improving. Where the turntable already beats the CDs is in imaging. Whew, once this thing is tuned in, it's gonna be great! I have a two record set of Gershwin music played on two pianos by Frances Veri and Michael Jamanis. On my inexpensive, Technics TT, I can't always distinguish the separate pianos. No problem now! At this point the turntable is only the first proto-type. I made a base from four pieces of MDF stacked and bolted together with ten 1/4" bolts. The MDF dimensions are 12 1/4" front to back. The front half of the 'table is 12 1/4" wide and the back half is 15" inches wide to provide space for the arm board. In the future I will separate the sheets of MDF with a couple layers of lead sheet and perhaps one of sorbothane. I don't have cones yet, but do to a small engineering miscalculation, the bolts that hold the thing together are about 1/4" to long and support the turntable. Later today, I will put washers under four of these so only they will be supporting the 'table. Eventually, when I recover from current cash hemorrhaging, cones will be installed. I put the motor on the tonearm side. It makes for a more compact turntable. At this point it is sitting on one of those thick pieces of deadening, rubbery material they sell for the insides of speakers. Unless I discover some reason to change, I will leave it there on future versions of the TT. This would be very easy to change, if necessary. The prototype arm board came out dead simple. I used MDF for this also. It is made out of four layers of MDF - the top and bottom are 3/4" thick and the two center ones are 1/8". Coincidentally, this makes the top edge of my Rega 250b almost perfectly parallel. The top of the tonearm at the bearing is 3 26/32" high. At the top of the headshell, it is 3 and 25/32". If needs be, I can raise the back with shims. I'm not sure about raising the front. I will probably put a mat on the platter to start my investigations. I haven't started tuning the VTA and SRA at all yet. The arm board is two inches wide. The top piece of MDF, that the tonearm is mounted on, is 3 1/2" long The hole for the tonearm centered in the rear inch and a half. The three supporting pieces are two inches long and mounted beneath the front half. This turned out really nice as it leaves total access to the tonearm post and nut. I hope it will make adjusting the VTA very easy. I cut the front of the armboard to look like this: \_/. It is cosmetically appealing and puts a little extra space between the board and the fishing line going to the motor pulley. Thom, you were right, using an oblong arm board with an eccentric pivot makes setting the lateral tone arm alignment a snap! I used the alignment protractor that is most graciously offered gratis from "Enjoy the Music to line up my tonearm and cartridge. Using your oblong armboard idea, Thom, it was incredibly easy to set this. And I'm sure there is a mathmatical explanation, but I will say that, most serendipitously, when the stylus lined up to the dot on the protractor, the over hang came out a perfect 11/16". I should have, but haven't measured the arm pivot to spindle distance, yet. I guess I assumed that if the alignment is so perfect and the overhang is so spot on, the length must be right. Ya, famous last words, huh? I'm listening to some Dave Brubeck as I write. Lordy, I'm gonna love this turntable! Already, it sounds so good. I haven't started tweeking at all, yet. I'll probably be kicked off the Teres list and Joenet too, after I admit this. Well folks, I don't have a gauge for checking my tracking force. I know I have an ancient half-moon postal scale around here somewhere. The trouble with that thing, is when I'm done using it, I'm usually in no shape to remember to put it away ;>) I do have an old Sure test record, "An Audio Obstical Course". It plays different instruments at four levels each. The narrator says that all cartridges should track OK in the low levels but only the best won't bounce around in the fourth level. It has a blank space for setting the anti-skating, as well. So I set the stylus force to where the thing breaks up on the fourth level of the tests. Then I sent the anti-skating. My gut feeling is I'm running a little light. But, I'm afraid to set it any heavier. God, I probably should put off playing records 'til I get a gauge. Naw... I did order one from the 'net yesterday. Hopefully, the gauge and the Cardas Test Suite LP will be here by Friday. I definately need to get going on a better phone stage. I think I have finally outgrown the $25.00 one I'm using now. Gosh, there's a lot of hum. Of course, the power supply is mounted about two inches from the pc board. I've decided to build the Pacific preamp designed at Mr. Walters at Le Maison de l'Audiphile. It uses 2SK170s and will fit into the base of the turntable. I need to get with Ron Wellborne about some parts. I hope he isn't off, gallavantin' around the countryside somewhere. I guess, going sand, I'm really risking being kicked off these lists! Well folks, sorry to make this so long. I'm playing some Paul Butterfield, now. Hmm, what will it be while I get ready for work? Cheers, Paul Subject: Re: [teres] Wow, the fat lady sings! Date: Wed, 6 Sep 2000 12:17:10 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com --- Paul Croft wrote: > Hi folks, > Well, I got my tone arm mounted last night. Put the > fishing string back on > and listened to my twenty year old copy of J.J. > Cale's "Naturally" By golly, > even without tuning, this one is better than the CD! > > Seriously, this Teres sounds pretty darned good just > starting out. The Denon > DL-103 cartridge does have some breaking in to do. > The music is a little > recessed and distant. After two hours of listening > though, this is already > improving. Where the turntable already beats the CDs > is in imaging. Whew, > once this thing is tuned in, it's gonna be great! I > have a two record set of > Gershwin music played on two pianos by Frances Veri > and Michael Jamanis. On > my inexpensive, Technics TT, I can't always > distinguish the separate pianos. > No problem now! > > At this point the turntable is only the first > proto-type. I made a base from > four pieces of MDF stacked and bolted together with > ten 1/4" bolts. The MDF > dimensions are 12 1/4" front to back. The front half > of the 'table is 12 > 1/4" wide and the back half is 15" inches wide to > provide space for the arm > board. In the future I will separate the sheets of > MDF with a couple layers > of lead sheet and perhaps one of sorbothane. I don't > have cones yet, but do > to a small engineering miscalculation, the bolts > that hold the thing > together are about 1/4" to long and support the > turntable. Later today, I > will put washers under four of these so only they > will be supporting the > 'table. Eventually, when I recover from current cash > hemorrhaging, cones > will be installed. -----------------------snip------------- Hmm....1/4" bolts, eh? You could probably screw the cones right onto four or them.... Igor __________________________________________________ Do You Yahoo!? Yahoo! Mail - Free email you can access from anywhere! http://mail.yahoo.com/ Subject: Re: [teres] Wow, the fat lady sings! Date: Wed, 6 Sep 2000 13:01:53 -0700 From: Thom Mackris, Thom Mackris To: teres@aiko.com I think standard cones take 5/16" bolts ... don't take my fading memory for it however. Thom ----- Original Message ----- From: Igor Kuznetsoff To: Sent: Wednesday, September 06, 2000 12:16 PM Subject: Re: [teres] Wow, the fat lady sings! -----------------------snip------------- Hmm....1/4" bolts, eh? You could probably screw the cones right onto four or them.... Igor Subject: [teres] Re: [JN] Granite good/no good? Date: Wed, 6 Sep 2000 13:36:17 -0700 From: Thom Mackris, Thom Mackris To: Teres_List; Bernhard Kistner Hi Bernhard, Your ideas about belt tensioning are intriguing, especially because a couple of folks on the Teres List arrived at the same conclusions you did. I'm copying the Teres List in order that they can benefit from the synchronicity of your thoughts. An "enthusiastic" discussion ensued in March. Various techniques were proposed, including linear bearings, inclined planes, as well as other equally imaginitive (and more difficult to describe) arrangements for controlling belt tension. By this weekend, we will be putting the remaining unarchived e-mails on the website (approx 1000 posts) by category, so if you're interested, check back sometime next week. It seems as if the Teres List has become a sub list of the Joe List. I'll bet that half of the 70 or so people hanging out there are Joes. Roscoe Primrose has graciously set up the list on his server. For subscription instructions, check out Chris Brady's website at: http://reality.sgi.com/cbrady_denver/audio/ Go to the Teres DIY Turntable link. As I continue to think about this whole lead shot and mineral oil damping issue, I'm thinking that there will be too little volume in any armboard cavity to accomplish much damping. I think the benefits of a solid sandwich and its inherrent rigidity will outweigh the minimal damping that a 1" round by 1/2" deep cavity can provide - I can't imagine much more room than that on the armboard. BTW, I believe that Chris has inventoried several extra motors & controller kits, complete with the CNC machined motor mounting plate and pulley (Manfred's circuit converted to a donut shaped circuit board by Ron Welborne - tres chic!). Cheers, Thom ----- Original Message ----- From: Bernhard Kistner To: Thom Mackris Sent: Saturday, September 02, 2000 9:20 PM Subject: Re: [JN] Granite good/no good? Hello all, I regret to have joined the Joe-List too late. Is there a sub-list concerning a turntable called Teres? How to join?ranite good/no good? > the current dialog centers on assembling Manfred's > outrageously good motor controller design (thanks, Manfred!), Manfred told how he did it. Have to agree his concept is great, and the thing works great, too. I trashed my concept, his is better. Thank you, Manfred! Currently I am working on a new motor support: I change from Pabst GS 38 to maxon DC motor. My motor's silde rest may interest you: 1.the motor's back end is air-tightly encapsuled, the mechanical noise caused by the collector becomes inaudible. 2.the motor is mounted on a linear ball bearing and can move along a straight through motor spindle and platter spindle. A weight on a thread pulls the motor sled away from the platter spindle and applies a constant, adjustable belt tension. Manfred demonstrated me that wrong belt tension can drive his I-regulator funny; besides that I wished to find out for long if and how much the belt tension influences the sound. From theory, the case of maximum constant belt slip should yield the best sound as the motor acts as pure intergrator then and its speed variations are equalled out completely (provided the platter has enough inertia to ensure dynamic constance of speed). > I'm thinking of a slightly different design from Chris'. There are no > drawings of these thoughts on the web site yet, but it's fairly simple. The > base will be a sandwich of: 3/16" aluminum - 2" acrylic - 3/16" aluminum > (pick your shape). There will be cavities in the acrylic into which I will > place lead shot and mineral oil for damping. I am curious whether the damping will do good or harm. Maybe a similar structure without cavities should be tried. To my experience, the tonearm has a lot of vibration energy to get rid of its socket. If you damp the tonearm's stand, you may deaden the sound. My SME V is mounted on a solid piece of Delrin, 20 mm thick, which is screwed in a solid block of plywood on all four edges. On loud passages of the record I can put my finger tip beneath the tonearm on the delrin board and feel the vibrations! > I really think there's something going on with these super decks being > unsuspended. Of course, now you also have to start thinkng of a stand for > your 'table to sit on. Do *not* neglect this aspect of the design ... it is > key to your success! Agreed, agreed! See my other postings. Wishing you all great music! Bernhard Subject: [teres] Guest Post From the Joe List Date: Wed, 6 Sep 2000 13:46:23 -0700 From: Thom Mackris, Thom Mackris To: Teres_List CC: bernhard.kistner@gmx.net Hello all, I just forwarded a response to this list from query on the Joe List from Bernhard Kistner. I noticed several other responses of his to a thread which began with a discussion about replacing a Rega plinth with a less resonant material. Bernhard thinks like us (and therefore, obviously has good taste ) and I thought you'd appreciate hearing his advice to this gentleman. He's been in communication with Hartmut and Manfred and is expecting to implement a Maxon motor & Manfred's controller in the near future. As I said, he has good taste. Enjoy, Thom ----- Original Message ----- From: Bernhard Kistner To: Joe-Net Sent: Saturday, September 02, 2000 8:00 PM Subject: RE: [JN] Rega mods Hello Steffen, hello all, <<<<<<<<<< > You need to redo the beltdrive with a new wheel on the motor, aprox 39,3 mm in diameter, if you go around the glasplatter, as we did. The glasplatter has a diameter of 295 mm, it turns with 33,333..... rpm, the EUROPEAN !!!!!!!!!!!( 50 Hz ) motor turns with 250 rpm, giving a ratio of 7,5, giving 39,333....mm for the motor wheel. <<<<<<<<<< Does the Rega glass platter have an outer diameter of narrow form tolerances? Or is it simply ground smooth? If the latter is the case, I wouldn't let the belt run on it becuase of diameter variations. OTOH, if you report better piano sound, the outer diameter should be ok. <<<<<<<<< > We made part of the motor wheel as big as a CD and 8mm thick to give some inertia to the motorsystem, as material we used delarin, some kind of plasik we could got hands on at that time. If you go for such a big / heavy wheel too, you need to suspend the motoraxel to protect the motorberings. <<<<<<<<< A syncronous motor is capable of rotational oscillations. Adding inertia to the motor may tune the resonance of this oscillation away from your working speed. But if you are unlucky, you may enhance 33 1/3 performance and worsen 45. Maybe a better way to replace the motor by a type showing no torque ripple andincapable of oscillations: DC motors manufactured by Faulhaber or Maxon serve well here. <<<<<<<<< > We use common cotton thread as belt, conecting the ends with a knot, no glue. > We think the sound got much more rocksolid, redusing wow and flutter, that is especially clear on pianomusic. <<<<<<<<< You and I use a tread or magnetic tape or whatever, but no rubber belt. Our belts are stiff against stretching and slippery. So there is no mutual exchange of potential rotation energy possible between platter and motor. The prereqisiste for rotational oscillation is missing. This is GOOD! No speed oscillations allowed. Therefore the whole sound spectrum improves, therefore piano music sounds so much better. Thread or magnetic tape? Some people report that magnetic tape sounds better than strings. I also tried cotton thread. I use a string of Kevlar so far, stiffer, more slippery, sounds better, wears earlier. Both share one annoying property: from time to time the knot insists to pass the pulley on the inner side instead, as intended, on the outer side. Makes me crazy! And to knot the string in a way it gets not twisted is high art, only succesful after several hours of deep meditation. The knot problem is reason enough to use magnetic tape as belt. Hope I could contribute some understanding. Wishing great music to all! Bernhard ----- Original Message ----- From: Bernhard Kistner To: Joe-Net Sent: Saturday, September 02, 2000 8:01 PM Subject: RE: [JN] Rega mods Hello Richard, hello all, > I recently (well maybe feb. or march) replaced the plinth on my Rega 3 > with one made of solid oak. Some 2in X6in. pieces of oak doweled and glued > together then cut to size. Misunderstanding, I have to blame my dictionary. "Plinth" reads to me like the base plate a complete turntable is positioned on, but obviously the term is also used for the turntable's body. I would never advise to make a turntable's body fom any stone alone, too resonant. For this piece oak wood is great. My turntable's body is manufactured from waterproof mahogany plywood. Birch plywood also serves well. What I understood as plinth is the base plate, the baby gravestone the turntable is sitting on. There I would prefer Diabas/Greenstone or Granite because of the relative absence of resonances and of the sheer weight. Next mod of my turntable is to put this baby gravestone on an air spring suspension, for instance a bicycle tube. The combination of high mass and soft spring yields a very low system resonance. Maybe a decade below 20Hz. So-called supercritical damping because the lowest interesting frequency is located way above the system resonance. So the steps of your pet dinosaur can shake your feet but not your turntable. > I really like the sound I ended up with. Nice and fast, lost some of the > bass muddiness that Rega's are prone to and nice extension on both ends. > Mids are soooo smooth. The only fault I hear is some little extra motor > noise, but that is easily lived with. Maybe you try out a maxon DC motor? Hartmut Quaschik and Manfred Huber seem to be the experts here. I try it. Second next mod. But not a cheap one. > I investigated a granite plith but the slab by itself without any of the > holes cut and only one side polished was going to cost me Can$120.00. With > holes and such cut I was looking at Can$200.00 plus wich was way out of my > budget range. > Before deciding on a "rock" of some kind investigate some of the > hardwoods available. They pass the "thunk" test and can sound really good. Great, you seem to have fun with it. I join your recommendation! Buy the slab unmachined and put your whole turntable on it! Wishing you all great music, Bernhard P.S.: The Platine Verdier's body is made of stone, artificial stone which can be casted like concrete or plaster. But to my knowledge, noone tried out to replace this body by a block of oak wood having three times the thickness and thus the same weight. Would be stiffer and less resonant. Could be interesting ... OTOH, the German Scheu turntable kit has a body made from steel. Sounds great anyway. Bernhard Subject: RE: [teres] controller is here Date: Thu, 7 Sep 2000 05:08:31 -0700 From: Paul Croft, Paul Croft To: teres@aiko.com Hi Daus, Where do you find 800 and 1000 grit sand paper. I must shop in the wrong places. I went directly to the polishing paste and am disappointed with the results. Also, what would you recommend as a protective finish. I used Rustoleom high gloss clear finish. It chipped as I was playing around with the controller and I think I'll strip it off and start over. Enjoy building the controller and remember the magnafying glass! Thanks, Paul > -----Original Message----- > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > Daus Studenberg > Sent: Thursday, September 07, 2000 3:08 AM snip... > you start out with a fine grit wet sanding paper like > 800 grit, dip it in water and sand it by hand. After that, you work up to > 1000 grit with water and to whatever fine grit paper you want after that. > Just don't forget the water and bear in mind that it will take a LOT of > elbow grease. After that, use "Mother's" aluminum polish a few times and > you should have that professional "mirror" finish. > > Daus > Subject: RE: [teres] controller is here Date: Thu, 7 Sep 2000 07:32:08 -0700 From: Epstein, Jeremy, Epstein, Jeremy To: 'teres@aiko.com' You can get all sorts of metalworking tools and supplies from aircraft tool suppliers - you may want the "micromesh" polishing kit that they use to buff up the Plexiglass windows. Sorry, lost the URL for now. -j ========================================= Jeremy Epstein........jepstein@ndbcap.com ========================================= > > Hi Daus, > Where do you find 800 and 1000 grit sand paper. I must shop > in the wrong > places. Subject: Re: [teres] controller is here Date: Thu, 7 Sep 2000 08:11:16 -0700 From: Thom Mackris, Thom Mackris To: teres@aiko.com Another thought is that you'll find (if Chris' experiences are any baseline) that the plate gets quite warm to the touch from sinking the heat from the transistors. Is any particular clearcoat better under these circumstances? Thom ----- Original Message ----- From: Paul Croft To: Sent: Thursday, September 07, 2000 5:05 AM Subject: RE: [teres] controller is here Hi Daus, Where do you find 800 and 1000 grit sand paper. I must shop in the wrong places. I went directly to the polishing paste and am disappointed with the results. Also, what would you recommend as a protective finish. I used Rustoleom high gloss clear finish. It chipped as I was playing around with the controller and I think I'll strip it off and start over. Enjoy building the controller and remember the magnafying glass! Thanks, Paul > -----Original Message----- > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > Daus Studenberg > Sent: Thursday, September 07, 2000 3:08 AM snip... > you start out with a fine grit wet sanding paper like > 800 grit, dip it in water and sand it by hand. After that, you work up to > 1000 grit with water and to whatever fine grit paper you want after that. > Just don't forget the water and bear in mind that it will take a LOT of > elbow grease. After that, use "Mother's" aluminum polish a few times and > you should have that professional "mirror" finish. > > Daus > Subject: Re: [teres] controller is here Date: Thu, 7 Sep 2000 10:33:02 -0700 From: Chris Brady, Chris Brady To: teres@aiko.com Thom Mackris wrote: The plate does get warm, but not so warm that it would affect the finish. I would guess that almost any clear finish applied to the uprimed metal would not be very rugged. But hopefully our motor pods won't be subject to much abuse. I have used clear lacquer in the past and it seems to hold up well. Chris > > Another thought is that you'll find (if Chris' experiences are any baseline) > that the plate gets quite warm to the touch from sinking the heat from the > transistors. Is any particular clearcoat better under these circumstances? > > Thom > > ----- Original Message ----- > From: Paul Croft > To: > Sent: Thursday, September 07, 2000 5:05 AM > Subject: RE: [teres] controller is here > > Hi Daus, > Where do you find 800 and 1000 grit sand paper. I must shop in the wrong > places. I went directly to the polishing paste and am disappointed with the > results. Also, what would you recommend as a protective finish. I used > Rustoleom high gloss clear finish. It chipped as I was playing around with > the controller and I think I'll strip it off and start over. > > Enjoy building the controller and remember the magnafying glass! > Thanks, > Paul > > > -----Original Message----- > > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > > Daus Studenberg > > Sent: Thursday, September 07, 2000 3:08 AM > > snip... > > > you start out with a fine grit wet sanding paper like > > 800 grit, dip it in water and sand it by hand. After that, you work up to > > 1000 grit with water and to whatever fine grit paper you want after that. > > Just don't forget the water and bear in mind that it will take a LOT of > > elbow grease. After that, use "Mother's" aluminum polish a few times and > > you should have that professional "mirror" finish. > > > > Daus > > Subject: Re: [teres] controller is here Date: Thu, 7 Sep 2000 11:10:22 -0700 From: phclark, phclark To: teres@aiko.com What I have/am using is a buffing wheel(s) and metal polishing compound for finishing the mounting plates. I came up with this a few years ago when I was doing copper chassis. It involves a lot less hand work. In my case, since both pods, plus their plates and the base of the 'table itself are all brass, doing it without the benefit of machine would be madness. Brass (as well as aluminum) is pretty soft, so the manufacturer's recommended three grit/step process can, in my experience, be abbreviated to two. The first step involves a fairly aggressive compound which should take out the machining marks (I'm leaving some in, for the Jules Verne Look,) and actually gives a good finish by itself. The final compound will require sunglasses. I don't have any suggestions about aluminum, because it oxidizes so easily. My aluminum chassis I've polished as above and lacquered with some success, but usually not with *hot* components attached to the chassis itself. Tubes are isolated by the holes in the chassis and their sockets and power trannies don't get *that* hot (250v B+ doesn't take much transformer grunt) so lacquer is about all the experience I have. Peter C ----- Original Message ----- From: "Chris Brady" To: Sent: Thursday, September 07, 2000 9:31 AM Subject: Re: [teres] controller is here > Thom Mackris wrote: > > The plate does get warm, but not so warm that it would affect the finish. > I would guess that almost any clear finish applied to the uprimed metal > would not be very rugged. But hopefully our motor pods won't be subject to > much abuse. I have used clear lacquer in the past and it seems to hold up > well. > > Chris > > > > Another thought is that you'll find (if Chris' experiences are any baseline) > > that the plate gets quite warm to the touch from sinking the heat from the > > transistors. Is any particular clearcoat better under these circumstances? > > > > Thom > > > > ----- Original Message ----- > > From: Paul Croft > > To: > > Sent: Thursday, September 07, 2000 5:05 AM > > Subject: RE: [teres] controller is here > > > > Hi Daus, > > Where do you find 800 and 1000 grit sand paper. I must shop in the wrong > > places. I went directly to the polishing paste and am disappointed with the > > results. Also, what would you recommend as a protective finish. I used > > Rustoleom high gloss clear finish. It chipped as I was playing around with > > the controller and I think I'll strip it off and start over. > > > > Enjoy building the controller and remember the magnafying glass! > > Thanks, > > Paul > > > > > -----Original Message----- > > > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > > > Daus Studenberg > > > Sent: Thursday, September 07, 2000 3:08 AM > > > > snip... > > > > > you start out with a fine grit wet sanding paper like > > > 800 grit, dip it in water and sand it by hand. After that, you work up to > > > 1000 grit with water and to whatever fine grit paper you want after that. > > > Just don't forget the water and bear in mind that it will take a LOT of > > > elbow grease. After that, use "Mother's" aluminum polish a few times and > > > you should have that professional "mirror" finish. > > > > > > Daus > > > > Subject: Re: [teres] controller is here Date: Thu, 7 Sep 2000 11:21:11 -0700 From: Daus Studenberg, Daus Studenberg To: teres@aiko.com You can find it in a hardware store.. the plain assortment of wet sanding paper should do it. I think I may have left out a step . I think will also used a rubbing compound with a power buffer and then the aluminum polish. I am going to ask some of the Formula 1 guys at school what they used. I will be fixing up the plate this weekend, so I will post my results. As for the protective coating, we never used one..then again we did always use aluminum polish. I am looking around for a good coating myself. I believe most of our electronic cases that have aluminum front panels have a polyurethane coating. Otherwise, the best way is to anodize it. I knew of someone who had anodizing of some parts done inexpensively by including his small batch with a large batch that was being anodized. I'll keep everyone posted. Daus ----- Original Message ----- From: Paul Croft To: Sent: Thursday, September 07, 2000 4:05 AM Subject: RE: [teres] controller is here > Hi Daus, > Where do you find 800 and 1000 grit sand paper. I must shop in the wrong > places. I went directly to the polishing paste and am disappointed with the > results. Also, what would you recommend as a protective finish. I used > Rustoleom high gloss clear finish. It chipped as I was playing around with > the controller and I think I'll strip it off and start over. > > Enjoy building the controller and remember the magnafying glass! > Thanks, > Paul > > > -----Original Message----- > > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > > Daus Studenberg > > Sent: Thursday, September 07, 2000 3:08 AM > > snip... > > > you start out with a fine grit wet sanding paper like > > 800 grit, dip it in water and sand it by hand. After that, you work up to > > 1000 grit with water and to whatever fine grit paper you want after that. > > Just don't forget the water and bear in mind that it will take a LOT of > > elbow grease. After that, use "Mother's" aluminum polish a few times and > > you should have that professional "mirror" finish. > > > > Daus > > > Subject: RE: [teres] Wow, the fat lady sings! Date: Thu, 7 Sep 2000 17:56:26 -0700 From: Schei, Kenneth, Schei, Kenneth To: 'teres@aiko.com' Paul: Kudos on your efforts; you're an inspiration to those of us who will be following. I will also be using laminated MDF for my TT base, because it's within my fabricating abilities, and because I think that MDF is a good material for the application. I will use multiple layers that are glued under pressure (clamps or weights). I will probably use common carpenter's glue which I don't think is a bad material either. Such a base will be cheap and easy and will do me for a while, if not permanently. I plan on cherry veneer with solid cherry wrapping the edges which should contrast nicely with the acrylic platter and brass motor pod. My base will be a rectangle with Golden Ratio dimensions to minimize spurious resonances. I also will use an arm board with the eccentric pivot for adjusting overhang - what a great idea! Cheers, Ken > -----Original Message----- > From: Paul Croft [SMTP:pcroft@iximd.com] > Sent: Wednesday, September 06, 2000 7:39 AM > To: Teres > Subject: [teres] Wow, the fat lady sings! > > Hi folks, > Well, I got my tone arm mounted last night. Put the fishing string back on > and listened to my twenty year old copy of J.J. Cale's "Naturally" By > golly, > even without tuning, this one is better than the CD! > > Seriously, this Teres sounds pretty darned good just starting out. The > Denon > DL-103 cartridge does have some breaking in to do. The music is a little > recessed and distant. After two hours of listening though, this is already > improving. Where the turntable already beats the CDs is in imaging. Whew, > once this thing is tuned in, it's gonna be great! I have a two record set > of > Gershwin music played on two pianos by Frances Veri and Michael Jamanis. > On > my inexpensive, Technics TT, I can't always distinguish the separate > pianos. > No problem now! > > At this point the turntable is only the first proto-type. I made a base > from > four pieces of MDF stacked and bolted together with ten 1/4" bolts. The > MDF > dimensions are 12 1/4" front to back. The front half of the 'table is 12 > 1/4" wide and the back half is 15" inches wide to provide space for the > arm > board. In the future I will separate the sheets of MDF with a couple > layers > of lead sheet and perhaps one of sorbothane. I don't have cones yet, but > do > to a small engineering miscalculation, the bolts that hold the thing > together are about 1/4" to long and support the turntable. Later today, I > will put washers under four of these so only they will be supporting the > 'table. Eventually, when I recover from current cash hemorrhaging, cones > will be installed. > > I put the motor on the tonearm side. It makes for a more compact > turntable. > At this point it is sitting on one of those thick pieces of deadening, > rubbery material they sell for the insides of speakers. Unless I discover > some reason to change, I will leave it there on future versions of the TT. > This would be very easy to change, if necessary. > > The prototype arm board came out dead simple. I used MDF for this also. It > is made out of four layers of MDF - the top and bottom are 3/4" thick and > the two center ones are 1/8". Coincidentally, this makes the top edge of > my > Rega 250b almost perfectly parallel. The top of the tonearm at the bearing > is 3 26/32" high. At the top of the headshell, it is 3 and 25/32". If > needs > be, I can raise the back with shims. I'm not sure about raising the front. > I > will probably put a mat on the platter to start my investigations. I > haven't > started tuning the VTA and SRA at all yet. > > The arm board is two inches wide. The top piece of MDF, that the tonearm > is > mounted on, is 3 1/2" long The hole for the tonearm centered in the rear > inch and a half. The three supporting pieces are two inches long and > mounted > beneath the front half. This turned out really nice as it leaves total > access to the tonearm post and nut. I hope it will make adjusting the VTA > very easy. I cut the front of the armboard to look like this: \_/. It is > cosmetically appealing and puts a little extra space between the board and > the fishing line going to the motor pulley. > > Thom, you were right, using an oblong arm board with an eccentric pivot > makes setting the lateral tone arm alignment a snap! I used the alignment > protractor that is most graciously offered gratis from "Enjoy the Music to > line up my tonearm and cartridge. Using your oblong armboard idea, Thom, > it > was incredibly easy to set this. And I'm sure there is a mathmatical > explanation, but I will say that, most serendipitously, when the stylus > lined up to the dot on the protractor, the over hang came out a perfect > 11/16". I should have, but haven't measured the arm pivot to spindle > distance, yet. I guess I assumed that if the alignment is so perfect and > the > overhang is so spot on, the length must be right. Ya, famous last words, > huh? > > I'm listening to some Dave Brubeck as I write. Lordy, I'm gonna love this > turntable! Already, it sounds so good. I haven't started tweeking at all, > yet. > > I'll probably be kicked off the Teres list and Joenet too, after I admit > this. Well folks, I don't have a gauge for checking my tracking force. I > know I have an ancient half-moon postal scale around here somewhere. The > trouble with that thing, is when I'm done using it, I'm usually in no > shape > to remember to put it away ;>) > > I do have an old Sure test record, "An Audio Obstical Course". It plays > different instruments at four levels each. The narrator says that all > cartridges should track OK in the low levels but only the best won't > bounce > around in the fourth level. It has a blank space for setting the > anti-skating, as well. > > So I set the stylus force to where the thing breaks up on the fourth level > of the tests. Then I sent the anti-skating. My gut feeling is I'm running > a > little light. But, I'm afraid to set it any heavier. God, I probably > should > put off playing records 'til I get a gauge. Naw... I did order one from > the > 'net yesterday. Hopefully, the gauge and the Cardas Test Suite LP will be > here by Friday. > > I definately need to get going on a better phone stage. I think I have > finally outgrown the $25.00 one I'm using now. Gosh, there's a lot of hum. > Of course, the power supply is mounted about two inches from the pc board. > > I've decided to build the Pacific preamp designed at Mr. Walters at Le > Maison de l'Audiphile. It uses 2SK170s and will fit into the base of the > turntable. I need to get with Ron Wellborne about some parts. I hope he > isn't off, gallavantin' around the countryside somewhere. I guess, going > sand, I'm really risking being kicked off these lists! > > Well folks, sorry to make this so long. I'm playing some Paul Butterfield, > now. Hmm, what will it be while I get ready for work? > Cheers, > Paul > >