Subject: Re: [teres] Subchassis Design Layout Date: Wed, 1 Mar 2000 00:41:55 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Daus, Please try to find out more about that acrylic/lead material, it sounds interesting. I figure on using an MDF/lead/MDF sandwich, with an additional layer of carbon fiber sheet if I can swing it. Glue between the MDF & lead will be Swedac, a pricey vibration damping glue. Igor --- Thom Mackris / Joan Panzella wrote: > Hi Daus, > > We're moving toward convergance in an area where I > expected the design > principles & philosophies to vary much more than > they have. Certainly, > aesthetics will come into play as we envision our > ultimate analog altar :-) > For example, the staggared design doesn't sound as > if it suits your tastes. > Gordon Maughan is an advocate of sculpting away > excess mass in the > subchassis, somewhat like Chris' "4 poster" design > on the web page. I can't > wait until we're all finished with this project to > see all of the different > interpretations on a subchassis. > > One appealing aspect of the "staggared" design I put > out to the list earlier > today is that the pieces will be cut separately - > I'd order 3 rectangles > (15" x 19") and 2 rectangles (14" x 18"). The only > cutting would be the > corner in the back to facilitate tonearm mounting > access / cable routing. > This could be easily done with a router, one piece > at a time. During > assembly, one would obviously be very careful in > lining up the pieces, but I > could sleep easily if I got the pieces to within > 1/32". > > This lead/acrylic combo is a facinating material. I > gather you don't know > much more about it. > > In several offline conversations, we're coming to an > agreement that rigidity > should be the first consideration and damping second > - the reason being that > you can come back and damp later where it's next to > impossible to make the > subchassis more rigid at a later date. Obviously we > don't have to take this > to an extreme - we don't want something that rings > like a bell, in search of > rigidity, but you get my point. Sand and/or > sorbothene ought to do just > fine for damping after the fact. > > Cheers, > Thom > > > ----- Original Message ----- > From: Daus Studenberg > To: > Sent: Tuesday, February 29, 2000 10:40 PM > Subject: Re: [teres] Subchassis Design Layout > > > I like this multiple layer idea very much as I have > been considering it > myself. We need a good rigid,dense and energy > absorbing sheet for the > arm/platter coupling. I have come across a sample > four months ago in a > vibrations class that was a sheet of material that > had a high acoustic > transmission loss. This board appeared to be 1" > thick made from acrylic and > lead powder! It was also rigid as well. But for > the time being, I am > considering the design that uses multiple layers for > a constrained damping > type resonance control. I have been looking at a > company that sells > damping sheets, mainly the vinyl type. So here is > my design: one inch thick > sheet of acrylic -vinyl sheet - 3/4"mdf - vinyl > sheet - 3/4"mdf - vinyl > sheet - 3/4" acrylic. Its close to being 3.75" > thick and I may add another > layer. After I glue the pieces together and cut the > final block, I will > cover it with paper backed veneer. I am a bit > worried about the > acrylic/glue combo, but this is my tentative plan. > I plan on this idea to > be extremely resistant to acoustically induced > vibrations. I am also > assuming little floor induced vibrations though a > granite - sandbox > approach. The thing I am most concerned about in > the design is whether or > not I can veneer to acrylic and whether or not my > table saw will be "happy" > with cutting through MDF/vinyl/acrylic!! > > Daus > > > Here are my current thoughts on subchassis > design... very art deco / Frank > > Lloyd Wright'ish. > > > > I haven't thought through the materials yet, > although in the interest of > > economy, I think that they will be either all > acrylic, or a combination of > > acrylic & MDF. The top layer will most definitely > be acrylic or something > > else that's stiff. I'm favoring rigidity over > outright damping, because > it > > seems to me that damping can always be addressed > later (i.e. a sandbox, or > > whatever). You can't go back and stiffen up the > structure too easily > after > > the fact. > > > > > __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com Subject: RE: [teres] Motor/supply kit Date: Wed, 1 Mar 2000 01:15:39 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: Thom G. Mackris CC: Thom G. Mackris Stanley, Using any metal other than lead (in a sandwich construction) in the subchassis would be a serious mistake, with or without Soundcoats. It would be too resonant, inherently, no matter what you do. You would only be fighting the inevitable. There is a **very** long list of materials far more suitable for this purpose, and quite a few have been discussed already, and at length. There is a wealth of information already in the digests, which Thom sweated endless hours over. Take advantage of it. Perhaps Thom should have named the digests FAQ's instead of digests, since normal newsgroup etiquette presumes that a new person has read the FAQ's before posting. Yes, I know it looks like an awful lot to read up on, but you won't regret it, there's good stuff there. The subchassis will be subject to more discussion, of course, but we will accomplish more if we could start with the existing knowledge base, and move forward from that. The use of metal in the subchassis would be best limited to decorative veneers, such as, perhaps, a nice engraved plaque saying "Teres". You are, perhaps, being somewhat optimistic in expecting a little piece of Delrin, however good a choice for its job, to take care of all vibration sinking duties. That sexy little round pedestal chassis is intriguing, and, as you observe, less prone to airborne vibration. Igor --- Stanley Goudge wrote: > I think the round plate is the way to go, but if > it's 1/4 inch thick a motor recess is necessary so > that the > pulley can be mounted close as possible to the > motor. Right now my vision for the Teres would be > similar to the Simon York design, using a small > circular subchassis and a small arm board for > increased immunity to > airborne and support vibrations. I think smaller is > better for this design given the use of derin for > the thrust bearing, > this should offer low noise without the need for a > large vibration sink. I'm thinking of using 2 to 2.5 > inch thick x 7 to 8 inch dia. > brass or stainless steel for the subchassis, maybe > sandwiched with Soundcoats CN material. But this > could all change > the more I think and learn from you guys. > > Thanks guys, > Stan > > At 11:36 AM 2/29/2000 -0700, Mackris, Thom G. wrote: > > > >Although I am gravitating toward a big honkin' > rectangular motor/controller > >"block" much like Chris' first POV ray drawing and > the Amazon Reference > >'table, I can see a real benefit to a circular > plate. > > > >A circular plate would facilitate periodic rotation > to facilitate equal wear > >on the motor bushing. If the holes (8 to 12) were > drilled via CNC, we'd be > >guraranteed that they were symetrical and could be > mounted in more than one > >orientation. The idea of 1/4" thickness or greater > is appealing from a > >rigidity standpoint. I'll bet we're talking about > only $15 per unit in the > >quantities we'd be ordering (a guess). > > > >Cheers, > >Thom > > > >-----Original Message----- > >From: Chris Brady [mailto:cbrady@sgi.com] > >Sent: Tuesday, February 29, 2000 10:29 AM > >To: teres@aiko.com > >Subject: [teres] Motor/supply kit > > > > > >I am wondering if there would be interest in > including > >a motor mounting plate in the motor/controller kit. > >I expect that there will be a lot of different > shapes and > >sizes of motor pods, but perhaps we can agree on a > single > >mounting plate design and benefit from a quantity > discount. > > > >I am thinking that a round mounting plate, say 4" > in diameter > >with mounting holes around the edge would work for > either a > >round or rectangular motor pod. We could each make > our own > >but with enough units they could be precision made > on a NC > >mill at a reasonable cost. If made from fairly thin > aluminum > >(1/16 - 1/8") it would be inexpensive. However, we > could > >also opt for a more expensive design made from 1/4 > - 3/8" > >aluminum with nice recessed holes for cap screws > and an > >anodized finish. The thicker plate may not work > any better > >but it would sure look sweet. > > > >Chris > > > > __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com Subject: Re: [teres] FW: Teres and carbon fiber Date: Wed, 1 Mar 2000 02:32:13 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Thorough analysis, Thom. I would add that anyone wanting to go even thicker than 2 1/4" can actually do so easily enough by rebating the bottom of the subchassis to sink the nut within it. Igor --- "Mackris, Thom G." wrote: > All, > > Steve asked me to forward the attached e-mail to the > list, as he's not > subscribed from his work e-mail. Thanks for doing > the research, Steve. You > might want to first read Steve's post at the end of > this e-mail before > reading my comments which immediately follow. > > Thom's comments .... > > With all fairness to DJ Casser, and respecting that > he's in business to make > money, my original thoughts when you reported on his > offer to mold lots of > carbon for us was that this was a great business > opportunity for him. Take > this in light of the fact that I own and love his > racing cones under my BAT > preamp. I respect the fact that he's not inclined > to give away any > proprietary information, but his comments don't > really give us any new > information and certainly don't address any issues > that this design hasn't > already accounted for. Had the collective knowledge > of this group not been > through this rigorous design exercise, I might be > inclined to sign him up > for some of his design talents, but after the fact, > I'd have to humbly say > that perhaps he should be hiring us for advice :-)) > > Addressing the issue of a bare acrylic platter, we > had discussions early on > about the record/platter surface. Two main schools > of thought emerged: > > (1) There may be some who chose to experiment > with various mat materials > > (2) Imperfect clamping may be the reason that DJ > reported a bright sound > with bare acrylic. > > My Merrill has a thin coating of lead on top of > acrylic. I would expect > this to sound similar to acrylic as far as > "brightness" is concerned, and > yet my Merrill is very well damped, considerably > less "ringy" than the > average unclamped, felt mat, Linn LP12. > > The Merrill has a periphery clamp which results in > the entire record being > in good contact with the platter. The Oracle and > VPI use a reflex clamp (a > washer on the spindle, under the record in > combination with a center clamp > that exerts downward pressure at the edge of the > record label). The Well > Tempered takes the reverse approach by dishing a > concavity into the plater > in conjunction with a flat clamp. > > All three of these methods address the problem of > flattening out the record > to make good contact with the platter without using > vacuum, albeit slightly > differently. I'm sure we've left ourselves with > plenty of options as far as > optimizing the record/platter interface and reducing > the ringing that DJ > reports having experienced. > > With all due respect to DJ Casser, I have to wonder > what variables he was > controlling when he worked with varying platter and > subchassis thicknesses. > Was the thrust surface of the bearing up to the task > of a heavier (thicker) > platter? Was the geometry of the bearing optimized > to reduce the > "teeter-toter" effect of so much mass? > > With respect to a thick, carbon fiber subchassis and > armboard sounding harsh > - I'd be interested to see what else changed at the > same time. Most likely, > the thick armboard was accompanied by the thicker > platter (to raise the > tonearm to the correct playing height) - see above > comments about thrust > plate & teeter-totter. I'll bet he beefed up the > subchassis at the same > time he went to a thicker platter (thinking he > needed to support the extra > mass of the platter without flexing). Perhaps he > actually **improved** the > resolution of the system and was now hearing an > **inferior** bearing, > bearing-platter geometry or motor/controller. > > The possibilities are indeed endless, but the good > news is, I believe we > have all of our bases covered as far as allowing > room for experimentation. I > appreciate your research and his offer to help, but > in the absence of a > complete story, his comments don't really help us > much or tell me that we're > headed in the wrong direction. They do confirm that > we will be > experimenting :-) > > BTW, the threaded area of the bearing will > accomodate any thickness > subchassis we choose, from approx 3/4" to approx 2 > -1/4". We specifically > allowed for choice and experimentation here too. We > can experiment to the > point that we never end up listening to music :-)) > If one wanted a > ridiculously thin subchassis (thinner than 3/4" !!!) > for some insane reason, > one could insert a couple of spacers on the top of > the subchassis. Hell, we > could have this baby flopping in the breeze if we > chose :-)) > > Thanks again for doing the research, > Thom > > Steve's post follows ... > > > -----Original Message----- > From: Brooks, Steve [mailto:Steve.Brooks@turner.com] > > Sent: Tuesday, February 29, 2000 1:31 PM > To: 'Mackris, Thom G.'; 'brookss@bellsouth.net' > Subject: Teres and carbon fiber > > > Thom, > can you post this to the mail list..I'm at work and > am only subscribed at > home. > thanks, Steve > > I spoke to DJ Casser today about the Teres and it > seems my earlier optimism > about his involvement was misplaced. He did not > realize that our design for > the bearing and platter were finalized. How does the > platter and bearing > effect the chassis and armboard? Here's the scoop in > his words: > > >1. we have found the thickness of our materials > are critical to >the sonic > >performance. 2" is way too thick: will sound > harsh. Been there, >Done > that. > >2. same for the armboard. > > So because our bearing is so long and our platter so > tall, carbon fiber > would not be a wise choice. Oh well. He also > expressed some concern over a > 3" acrylic platter...his words again: > > >the acrylic platter should have some damping > material of some sort > >implanted [lead, etc]. acrylic by itself will > sound bright. > > I realize this is a little late in the game, does > anyone have any idea if > this could be accomplished later? He told me you > would need a big lathe > (15"?) to drill the holes, as they would need to be > perfectly balanced. > > Anyway he is a really nice guy who is very > forthcoming. We just got to him a > little late in the game. Now how about Corian? > Steve Brooks > __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com Subject: RE: [teres] Motor/supply kit Date: Wed, 1 Mar 2000 10:43:29 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; teres@aiko.com I agree no wall warts please. If we do include a x-former my I recommend Signal Transformer PN A41-25-10, these have been measured to have high isolation as described by Gary Galo in Audio Amateur vol.26 no.4, mainly due to the dual bobbin design and 4K Hipot rating. They also have dual primaries for 120/220 vac service and dual secondarys for multiple outputs either 5vac or 10vac. And their cheap 25% discount for >25 pc = about $10. I read the discouraging email by DJ Casser regarding the platter design. If this is indeed a problem my I offer the same solution that Bill Firebaugh used for his acrylic platter in a upgraded platter called the Black Damped Platter. Which Bob Harley descibes as "completely transformed it" in Stereophile April 93. Bill used E-A-R SpecialtyComposites CN-38 or isodamp under the machined out platter. This is the same stuff the Navy uses for submarine hauls and I've used it (CN-12) on preamp amp chassis and MDF speaker cabnets with excellent measured and sonic results. Its killer stuff and sure would be easer that drilling holes for lead or brass not to mention that the platter needs to balanced afterwards. Of course any good high performance auto machine shop can do this for about $40. Right now the CN38 (.36" thick) is not in stock so there is a 4 week lead time and cost for 1 foot square is $15.48 @ qty less 100pc. CN-12 (.122" thick) is in stock for 1 foot square is $12.58 ( its does also come in 2.25' x 4' sheet) which would be perfect for subchassis dampning. Minium order is only $250 so who wants some? I'm gonna order some anyway, soon as I (or we) figure out what I need. Thanks, Stan At 06:02 AM 3/1/2000 -0500, Paul Croft wrote: >Hi Chris, >Ugh, no wall warts, please! Perhaps this is better left to the individual. >Since the switch and LEDs are so visible, I think most people would rather >select their own style and look. No reason to over-burden yourself with the >minutiae ;>) >Cheers, >Paul > >> -----Original Message----- >> From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of >> Chris Brady >> Sent: Wednesday, March 01, 2000 12:01 AM >> To: teres@aiko.com >> Subject: Re: [teres] Motor/supply kit >> >> >>(...pins) >> >> I am working on sourcing parts for the controller and have a few >> questions for the group. >> >> 1) Power xfmr - Should this be a wall wart or a small xfmr that >> can be mounted inside the motor pod? Or should we not include >> an xfmr in the kit so that everyone can do their own thing? >> I am leaning toward a wall wart. >> >> 2) Switch and LED's - The controller uses a single pushbutton >> switch and two LED's. There's tons of styles and types. >> Should I just choose what I think everyone would like or >> leave them out of the kit. >> >> Chris >> > Subject: Re: [teres] Re: belt material Date: Wed, 1 Mar 2000 12:57:22 -0700 From: Mikhail Karlin, Mikhail Karlin To: teres@aiko.com Yes, that or a mike or a piezo sensor would do, I guess, what I wish I had, though - a spectrum analyser in addition Michael On Wed, 1 Mar 2000, Igor Kuznetsoff wrote: > You could use that as your super sensitive pickup, > then. I suspect that in this group, probably pretty > much everyone is likely to have some old ones around, > it's only a matter of whether they are old & beat up > enough to use this way. I have at least two around > that I have been saving for *many* years for *just* > this sort of use, and have, in fact, already used them > in this manner, but on other projects. > > Igor > > --- Mikhail Karlin wrote: > > Igor, actually somebody(mybody) would have an old > > cartridge > > Michael > > > > On Fri, 25 Feb 2000, Igor Kuznetsoff wrote: > > > > > You could even use a cheap, beat up old cartridge > > as a > > > super-sensitive pickup. Heaven knows, nobody in > > > *this* group would have something like that > > around.... > > > > > > Igor > > > > > > --- Thom Mackris / Joan Panzella > > > wrote: > > > > Hi George, > > > > > > > > I've been thinking about your comments. My > > guess is > > > > that what we would need > > > > to some sort of transducer, like an acoustic > > guitar > > > > pickup which we could > > > > place on the subchassis while the various belts > > are > > > > spinning the platter. > > > > > > > > We could then pass this output through an > > amplifier > > > > and either listen to or > > > > measure the results as far as total output and > > > > frequency spectrum. I'm > > > > guessing that what we learn as far as the > > > > correlation between the noise we > > > > measure vs. good sound this will be equal > > > > combiations of engineering and > > > > magic :-)) Perhaps we will learn that some > > > > frequency spectrums are more > > > > benign and will sound better at a higher level > > than > > > > other frequencies do at > > > > a lower value. This would be interesting. > > > > > > > > This technique would be informative in terms of > > > > evaluating various > > > > suspension / damping schemes vs. audible results > > > > too. > > > > > > > > I wonder if on a cruder level of inquiry, that > > > > vibration levels at this > > > > level of sophistication are audible with a plain > > ol' > > > > stethescope? > > > > > > > > Comments? > > > > > > > > Cheers, > > > > Thom > > > > > > > > ----- Original Message ----- > > > > From: George Munger > > > > To: > > > > Sent: Wednesday, February 23, 2000 7:33 AM > > > > Subject: Re: belt material, was RE: [teres] > > > > synchronous vs.asynchronous > > > > motors; > > > > > > > > > > > > Hey there. I know not much, but Thom keeps > > saying > > > > to express ourselves > > > > so... > > > > Isn't there a way(s) we could try to perform > > some > > > > tests to obtain some > > > > quantitative data, once a list of possible belt > > > > materials is made? > > > > A) id the energy transmission levels of various > > > > belt materials to an > > > > acrylic platter (maybe we don't even need a > > Teres > > > > platter, just an acrylic > > > > one). > > > > 1) determine the various materials transmission > > > > values > > > > 2) determine if value changes relate to audible > > > > changes > > > > 3) determine other factors to check if stiff, > > > > lossy, available, etc. > > > > We then review the results. We could test an > > > > existing rubber TT/belt combo > > > > as a reference. Then make/obtain each available > > belt > > > > material, mag-tape, > > > > dental floss, etc. using ?? instrument(s) to > > > > determine quantitative values, > > > > then qualitative (listening) results. All other > > > > things being equal, we > > > > might get something of value here, maybe not... > > > > inquiring minds want to > > > > know. What to do? GM > > > > > > > > >>> "Sellek, Grant (TSA)" > > > > 02/22 10:55 > > PM > > > > >>> > > > > -----Original Message----- > > > > From: phclark [mailto:phclark@uswest.net] > > > > Subject: Re: [teres] synchronous vs. > > asynchronous > > > > motors > > > > > > > > 2. Elastic coupling is inevitable at some > > level. > > > > Non-compliant materials > > > > like magnetic tape would seem to be preferable > > to, > > > > say, string. > > > > > > > > > > =============================================================== > > > > > > > > Peter, I'm not entirely convinced about this, > > > > especially if we concede that > > > > the motor is not providing effective > > instantaneous > > > > speed correction. I would > > > > agree with the advantage of non-compliant > > materials > > > > if there were no > > > > tradeoffs, however I reckon the danger of a mag > > tape > > > > drive is that it will > > > > efficiently transmit any motor noise to the > > platter, > > > > either bearing-type or > > > > brush-type noise. We are trying to reduce that > > noise > > > > at its source with a > > > > good choice of motor, but that doesn't mean we > > can > > > > ignore the tranmission of > > > > noise through the drivetrain. Like Chris Brady > > said, > > > > take every possible > > > > measure. > > > > > > > > I don't want an elastic coupling either. Who > > wants > > > > the platter going boing > > > > boing on the end of a rubber band? I think this > > is > > > > what Peter and others who > > > > favour mag tape are trying to avoid. > > > > > > > > So I am in favour of a stiff but lossy > > drivetrain. > > > > Mag tape is stiff but not > > > > lossy. Rubber is slightly lossy but not stiff. > > The > > > > best candidate that comes > > > > to mind is string, or cotton thread! Does anyone > > > > have a better suggestion > > > > for a stiff, lossy material? What about leather? > > > > > > > > Grant > > > > > > > > Grant Sellek > > > > Adelaide, Australia > > > > grant.sellek@transport.sa.gov.au > > > > > > > > > > > > > > > > > > > __________________________________________________ > > > Do You Yahoo!? > > > Talk to your friends online with Yahoo! Messenger. > > > http://im.yahoo.com > > > > > > > > > > __________________________________________________ > Do You Yahoo!? > Talk to your friends online with Yahoo! Messenger. > http://im.yahoo.com > Subject: Re: [teres] Re: belt material Date: Wed, 1 Mar 2000 13:18:52 -0700 From: Kalman Rubinson, Kalman Rubinson To: teres@aiko.com On Wed, 1 Mar 2000, Mikhail Karlin wrote: > Yes, that or a mike or a piezo sensor would do, I guess, what I wish > I had, though - a spectrum analyser in addition If you have a PC with a soundcard, you do. There are many FFT programs out there. Kal Subject: Re: [teres] Subchassis Design Layout Date: Wed, 1 Mar 2000 17:00:50 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; teres@aiko.com Igor , I think you need a tight coupling between the lead and MDF in order for the lead to damp. With the Swedac glue you may decouple the lead from the MDF because of its elasticity. I'd use epoxy or that new polyurethane stuff. Swedac glue is mainly used for laminating wood to wood. Or why not try the isodamp stuff I described earlier. Its the clostest thing to a "synthetic lead" and you just peal and stick it. And once its cured it ain't coming off! It can be orderd with both sides with PSA (pressure sensitive adhesive). Stan At 10:41 PM 2/29/2000 -0800, Igor Kuznetsoff wrote: >Daus, > Please try to find out more about that >acrylic/lead material, it sounds interesting. I >figure on using an MDF/lead/MDF sandwich, with an >additional layer of carbon fiber sheet if I can swing >it. Glue between the MDF & lead will be Swedac, a >pricey vibration damping glue. > > Igor Subject: RE: [teres] Subchassis Design Layout - Isodamp Date: Wed, 1 Mar 2000 18:02:11 -0700 From: Mackris, Thom G., Mackris, Thom G. To: 'teres@aiko.com' Hotbot turns up 5 websites on the string "Isodamp". Four of them describe the product: http://www.faroc.com.au/~watno/vibratio.htm http://www.machinedesign.com/mfg/ear/damp_iso.htm http://www.earsc.com/isolate.htm http://www.marrison.com/ic/pages/D/damping.html The last one: http://www.digido.com/subwoofer.html says that this is the famous "Blu Tak" stuff. I'm thinking that the pressure sensitive adhesive sheets are the same only different :-) Quoting from this site: "Acoustician Johnson Knowles suggests a viscoelastic polymer pad material like EAR Isodamp C1002 or C1000. The internal damping characteristics of the viscoelastics are exceptionally effective as a speaker to stand interface material. U.S. Consultant Steve Desper recommends STIK-TAK by Devcon Corporation, available at your local hardware store. It's a cheap solution and works good. Australian Greg Simmons has found a similar product - marketed as 'Blue Tak': "Use enough of it relative to the weight of your speakers. For a small monitor weighing just over 20kg, I used four balls about 15mm in diameter (one under each corner). With 20kg on top of them, these balls squashed down to about 4mm or 5mm thickness, and held the monitor very firmly." Cheers, Thom -----Original Message----- From: Stanley Goudge [mailto:sgoudge@cisco.com] Sent: Wednesday, March 01, 2000 3:54 PM To: teres@aiko.com; teres@aiko.com Subject: Re: [teres] Subchassis Design Layout Igor , I think you need a tight coupling between the lead and MDF in order for the lead to damp. With the Swedac glue you may decouple the lead from the MDF because of its elasticity. I'd use epoxy or that new polyurethane stuff. Swedac glue is mainly used for laminating wood to wood. Or why not try the isodamp stuff I described earlier. Its the clostest thing to a "synthetic lead" and you just peal and stick it. And once its cured it ain't coming off! It can be orderd with both sides with PSA (pressure sensitive adhesive). Stan At 10:41 PM 2/29/2000 -0800, Igor Kuznetsoff wrote: >Daus, > Please try to find out more about that >acrylic/lead material, it sounds interesting. I >figure on using an MDF/lead/MDF sandwich, with an >additional layer of carbon fiber sheet if I can swing >it. Glue between the MDF & lead will be Swedac, a >pricey vibration damping glue. > > Igor Subject: RE: [teres] Motor/supply kit Date: Wed, 1 Mar 2000 20:10:41 -0700 From: Paul Croft, Paul Croft To: teres@aiko.com Stan, This sounds very interesting. I'd love about three square feet of the .36" stuff. Hmm, I was thinking for general use. Perhaps thinner would be better for the platter. Let me know the details and I'll send you the money. Thanks, Paul > -----Original Message----- > From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of > Stanley Goudge > Sent: Wednesday, March 01, 2000 11:36 AM > To: teres@aiko.com; teres@aiko.com > Subject: RE: [teres] Motor/supply kit > > > (snip...) Right now the CN38 (.36" thick) is not > in stock so there is a 4 week lead time and cost for 1 foot > square is $15.48 @ qty less 100pc. CN-12 (.122" thick) > is in stock for 1 foot square is $12.58 ( its does also come in > 2.25' x 4' sheet) which would be perfect for subchassis > dampning. Minium order is only $250 so who wants some? I'm gonna > order some anyway, soon as I (or we) figure out > what I need. > > Thanks, > Stan > >(More snipping...) Subject: RE: [teres] Motor/supply kit Date: Wed, 1 Mar 2000 20:21:10 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com Stan said, > Right now the CN38 (.36" > thick) is not > in stock so there is a 4 week lead time and cost > for 1 foot square is $15.48 @ qty less 100pc. > CN-12 (.122" thick) > is in stock for 1 foot square is $12.58 ( its > does also come in 2.25' x 4' sheet) which would > be perfect for subchassis > dampning. Minium order is only $250 so who wants > some? I'm gonna order some anyway, soon as I (or > we) figure out > what I need. Stan, I'll take 16" square if that is an option. Jon Lane Subject: Re: [teres] Motor/supply kit Date: Thu, 2 Mar 2000 00:48:25 -0700 From: Thom Mackris / Joan Panzella, Thom Mackris / Joan Panzella To: teres@aiko.com This stuff sounds interesting, Stanley. Note that the current platter to subchassis clearance is 1/8" (.125"), unless we add to that by inserting a 1/8" fender washer between the bearing and subchassis. Another option is to route a rebate in the subchassis (with a high point at the bearing mounting area) for additional clearance. Remember that we will be affixing a strobe disk on the bottom side of the platter. Will this present any problems with the Isodamp? I'm guessing the only problem is one of A/B'ing the differences (removing the Isodamp after trying it). I can't imagine something like this hurting the sonics, but you never know. Cheers, Thom ----- Original Message ----- From: Stanley Goudge To: ; Sent: Wednesday, March 01, 2000 9:35 AM Subject: RE: [teres] Motor/supply kit I agree no wall warts please. If we do include a x-former my I recommend Signal Transformer PN A41-25-10, these have been measured to have high isolation as described by Gary Galo in Audio Amateur vol.26 no.4, mainly due to the dual bobbin design and 4K Hipot rating. They also have dual primaries for 120/220 vac service and dual secondarys for multiple outputs either 5vac or 10vac. And their cheap 25% discount for >25 pc = about $10. I read the discouraging email by DJ Casser regarding the platter design. If this is indeed a problem my I offer the same solution that Bill Firebaugh used for his acrylic platter in a upgraded platter called the Black Damped Platter. Which Bob Harley descibes as "completely transformed it" in Stereophile April 93. Bill used E-A-R SpecialtyComposites CN-38 or isodamp under the machined out platter. This is the same stuff the Navy uses for submarine hauls and I've used it (CN-12) on preamp amp chassis and MDF speaker cabnets with excellent measured and sonic results. Its killer stuff and sure would be easer that drilling holes for lead or brass not to mention that the platter needs to balanced afterwards. Of course any good high performance auto machine shop can do this for about $40. Right now the CN38 (.36" thick) is not in stock so there is a 4 week lead time and cost for 1 foot square is $15.48 @ qty less 100pc. CN-12 (.122" thick) is in stock for 1 foot square is $12.58 ( its does also come in 2.25' x 4' sheet) which would be perfect for subchassis dampning. Minium order is only $250 so who wants some? I'm gonna order some anyway, soon as I (or we) figure out what I need. Thanks, Stan At 06:02 AM 3/1/2000 -0500, Paul Croft wrote: >Hi Chris, >Ugh, no wall warts, please! Perhaps this is better left to the individual. >Since the switch and LEDs are so visible, I think most people would rather >select their own style and look. No reason to over-burden yourself with the >minutiae ;>) >Cheers, >Paul > >> -----Original Message----- >> From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of >> Chris Brady >> Sent: Wednesday, March 01, 2000 12:01 AM >> To: teres@aiko.com >> Subject: Re: [teres] Motor/supply kit >> >> >>(...pins) >> >> I am working on sourcing parts for the controller and have a few >> questions for the group. >> >> 1) Power xfmr - Should this be a wall wart or a small xfmr that >> can be mounted inside the motor pod? Or should we not include >> an xfmr in the kit so that everyone can do their own thing? >> I am leaning toward a wall wart. >> >> 2) Switch and LED's - The controller uses a single pushbutton >> switch and two LED's. There's tons of styles and types. >> Should I just choose what I think everyone would like or >> leave them out of the kit. >> >> Chris >> > Subject: Re: [teres] Motor/supply kit Date: Thu, 2 Mar 2000 09:55:58 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; teres@aiko.com Yea Thom, it sure will be tough to remove after the glue cures in about 24 hours , but easily before then, so listen quick I guess. Bill rebated his platter so thats its flush, which you can do with a good router, but its almost impossible to cut a smooth surface of more than a few inches wide. Maybe if you use several passes with the router and set it up so that the final pass cuts only a hairs width and use steady continuous movement. Don't know what size Bill used, but I guess maybe a 3" to 4" wide ring and maybe 1/4 to 1/2" from the outside of the platter. He also uses this same stuff for the foutainhead sandwich subchassis, but used thinner material, probably CN-06 (.060") material. I see no problem with the strobe disk, man it would be cool to have the disk made from thin aluminum and glue it to the isodamp as this would increase the efficiency of the material by providing extensional damping. But I think really its not needed. At 11:51 PM 3/1/2000 -0700, Thom Mackris / Joan Panzella wrote: >This stuff sounds interesting, Stanley. Note that the current platter to >subchassis clearance is 1/8" (.125"), unless we add to that by inserting a >1/8" fender washer between the bearing and subchassis. > >Another option is to route a rebate in the subchassis (with a high point at >the bearing mounting area) for additional clearance. Remember that we will >be affixing a strobe disk on the bottom side of the platter. Will this >present any problems with the Isodamp? > >I'm guessing the only problem is one of A/B'ing the differences (removing >the Isodamp after trying it). I can't imagine something like this hurting >the sonics, but you never know. > >Cheers, >Thom > >----- Original Message ----- >From: Stanley Goudge >To: ; >Sent: Wednesday, March 01, 2000 9:35 AM >Subject: RE: [teres] Motor/supply kit > > > I agree no wall warts please. If we do include a x-former my I recommend >Signal Transformer PN A41-25-10, these have >been measured to have high isolation as described by Gary Galo in Audio >Amateur vol.26 no.4, mainly due to the >dual bobbin design and 4K Hipot rating. They also have dual primaries for >120/220 vac service and dual secondarys for multiple >outputs either 5vac or 10vac. And their cheap 25% discount for >25 pc = >about $10. > > I read the discouraging email by DJ Casser regarding the platter design. >If this is indeed a problem my I offer the same >solution that Bill Firebaugh used for his acrylic platter in a upgraded >platter called the Black Damped Platter. Which Bob Harley >descibes as "completely transformed it" in Stereophile April 93. Bill used >E-A-R SpecialtyComposites CN-38 or isodamp >under the machined out platter. This is the same stuff the Navy uses for >submarine hauls and I've used it (CN-12) on >preamp amp chassis and MDF speaker cabnets with excellent measured and sonic >results. Its killer stuff and sure would >be easer that drilling holes for lead or brass not to mention that the >platter needs to balanced afterwards. Of course >any good high performance auto machine shop can do this for about $40. Right >now the CN38 (.36" thick) is not >in stock so there is a 4 week lead time and cost for 1 foot square is $15.48 >@ qty less 100pc. CN-12 (.122" thick) >is in stock for 1 foot square is $12.58 ( its does also come in 2.25' x 4' >sheet) which would be perfect for subchassis >dampning. Minium order is only $250 so who wants some? I'm gonna order some >anyway, soon as I (or we) figure out >what I need. > >Thanks, >Stan > >At 06:02 AM 3/1/2000 -0500, Paul Croft wrote: >>Hi Chris, >>Ugh, no wall warts, please! Perhaps this is better left to the individual. >>Since the switch and LEDs are so visible, I think most people would rather >>select their own style and look. No reason to over-burden yourself with the >>minutiae ;>) >>Cheers, >>Paul >> >>> -----Original Message----- >>> From: owner-teres@aiko.com [mailto:owner-teres@aiko.com]On Behalf Of >>> Chris Brady >>> Sent: Wednesday, March 01, 2000 12:01 AM >>> To: teres@aiko.com >>> Subject: Re: [teres] Motor/supply kit >>> >>> >>>(...pins) >>> >>> I am working on sourcing parts for the controller and have a few >>> questions for the group. >>> >>> 1) Power xfmr - Should this be a wall wart or a small xfmr that >>> can be mounted inside the motor pod? Or should we not include >>> an xfmr in the kit so that everyone can do their own thing? >>> I am leaning toward a wall wart. >>> >>> 2) Switch and LED's - The controller uses a single pushbutton >>> switch and two LED's. There's tons of styles and types. >>> Should I just choose what I think everyone would like or >>> leave them out of the kit. >>> >>> Chris >>> >> > Subject: Re: [teres] Subchassis Design Layout Date: Thu, 2 Mar 2000 11:30:49 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Stan, Thanks for the analysis. I don't read it quite the same way as you do, but am planning to do some more testing. I have already played around with the Swedac, with both 3/4" MDF & 1/8" "hardboard" panels. "Hardboard" or "fiberboard"/pressed board-the stuff that "peg board" is made of, only without the holes, is a close relative of MDF, and has been around for as long as I can remember, in 1/8 & 1/4" thicknesses. It mimics the sonics of MDF, but, being thinner, is noisier, if laminated in just two layers, making the effects of a test lamination much easier to read/hear. On the other hand, if you were to laminate 3 x 1/4" with, say, the Swedac, the result would be *way* quieter than 3/4" of MDF, and just as stiff! If you also added something else, like carbon fiber... Swedac dries, not cures, and dries very slowly if bounded by materials that do not absorb any of its solvent (water, so far as I know), and this may account for it's use principally on wood. It acts much like ordinary wood glues in this respect. Practically speaking, at least one of the bonded materials would have to be wood or fiber composite such as MDF, and such a hybrid bond takes a long time to dry. I've tried bonding acrylic to fiberboard with it, and the bond is strong, but took forever, my objection to it. I would not be concerned about "decoupling" the lead, but would, rather, consider the Swedac an *additional* constrained layer in its own right. Perhaps Daus, in school for this very subject, if I got that right, will comment on this. I plan to do some more testing on various combinations, yet, using the (1/8") fiberboard modeling technique first, then confirming with MDF. The isodamp sounds interesting, as all such materials are to me, I will have to try it sometime. I would be concerned about the strength of both its bond, and the material itself (internally) within some of the uses I could put it to. For this reason, and others (such as a possible use on platters), the thinner version is particularly attractive. Specifically, if Manfred's new motor controller is designed like the earlier one he transmitted (I sure hope so, in this regard), it will require a strobe readout bonded to the bottom of the platter. (Manfred, or Chris, *does* it use that optical pickup?) So long as this is so, it might as well be bonded with some of this isodamp, no? Thanks for reminding me of the new polyurethane glues, I had noted to myself when I first heard of them that I wanted to experiment with them, but forgot all about it. An important factor in their use, as just discussed, would be how they set/dry when bounded by non-porous materials. Epoxy would work there, as it catalyzes, not "dries", but I would like to find a more compliant glue, not hard-to-brittleness like most epoxies (with age), but with an equivalent strength. Please don't suggest something like (ordinary) Silicone, that is totally unsuitable. I do have a two-part *catalyzed* silicone around, which I have used to make flexible cable covers, and other flexible coatings, and it is not only much tougher than the ordinary squeeze tube/cartridge type silicone, but also makes a very pretty, *smooth* coating on whatever is dipped into it, or painted with it before it starts to "kick" off. Additionally, it can be tinted any color you like prior to catalyzing (naturally, it is a slightly off-clear amber color). You can even mix in particulants like metalflake if you wanted. Very useful, and can be found in most art/drafting supply type stores, in the resins/modeling clays department. I might try a little (meaning a thin layer) of this to see how it performs. Ordinary silicone has poor internal self-damping characteristics, more like hard-set jello wiggling about than what we need, and weak, besides. Igor --- Stanley Goudge wrote: > Igor , I think you need a tight coupling between the > lead and MDF in order for the lead to damp. > With the Swedac glue you may decouple the lead from > the MDF because of its elasticity. I'd use > epoxy or that new polyurethane stuff. Swedac glue is > mainly used for laminating wood to wood. > Or why not try the isodamp stuff I described > earlier. Its the clostest thing to a "synthetic > lead" and > you just peal and stick it. And once its cured it > ain't coming off! It can be orderd with both sides > with > PSA (pressure sensitive adhesive). > > Stan > > > > At 10:41 PM 2/29/2000 -0800, Igor Kuznetsoff wrote: > >Daus, > > Please try to find out more about that > >acrylic/lead material, it sounds interesting. I > >figure on using an MDF/lead/MDF sandwich, with an > >additional layer of carbon fiber sheet if I can > swing > >it. Glue between the MDF & lead will be Swedac, a > >pricey vibration damping glue. > > > > Igor > > > __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com Subject: RE: [teres] Subchassis Design Layout - Isodamp Date: Fri, 3 Mar 2000 10:13:59 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; 'teres@aiko.com' Thom, The Blue Tak and Stick-Tac are the same product, but far different than isodamp. Blue Tak can be moulded like clay and I think was made for erasing type writer mistakes, then someone way back in the later 70's discoverd it was great for damping tonearms and headshells. Now audiophiles use it everywere on anything because its easy to get at any office supply. Stan At 04:43 PM 3/1/2000 -0700, Mackris, Thom G. wrote: >Hotbot turns up 5 websites on the string "Isodamp". Four of them describe >the product: >http://www.faroc.com.au/~watno/vibratio.htm >http://www.machinedesign.com/mfg/ear/damp_iso.htm >http://www.earsc.com/isolate.htm >http://www.marrison.com/ic/pages/D/damping.html > > >The last one: http://www.digido.com/subwoofer.html says that this is the >famous "Blu Tak" stuff. I'm thinking that the pressure sensitive adhesive >sheets are the same only different :-) Quoting from this site: > >"Acoustician Johnson Knowles suggests a viscoelastic polymer pad material >like EAR Isodamp C1002 or C1000. The internal damping characteristics of the >viscoelastics are exceptionally effective as a speaker to stand interface >material. > >U.S. Consultant Steve Desper recommends STIK-TAK by Devcon Corporation, >available at your local hardware store. It's a cheap solution and works >good. Australian Greg Simmons has found a similar product - marketed as >'Blue Tak': "Use enough of it relative to the weight of your speakers. For a >small monitor weighing just over 20kg, I used four balls about 15mm in >diameter (one under each corner). With 20kg on top of them, these balls >squashed down to about 4mm or 5mm thickness, and held the monitor very >firmly." > >Cheers, >Thom > > >-----Original Message----- >From: Stanley Goudge [mailto:sgoudge@cisco.com] >Sent: Wednesday, March 01, 2000 3:54 PM >To: teres@aiko.com; teres@aiko.com >Subject: Re: [teres] Subchassis Design Layout > > >Igor , I think you need a tight coupling between the lead and MDF in order >for the lead to damp. >With the Swedac glue you may decouple the lead from the MDF because of its >elasticity. I'd use >epoxy or that new polyurethane stuff. Swedac glue is mainly used for >laminating wood to wood. >Or why not try the isodamp stuff I described earlier. Its the clostest thing >to a "synthetic lead" and >you just peal and stick it. And once its cured it ain't coming off! It can >be orderd with both sides with >PSA (pressure sensitive adhesive). > >Stan > > > >At 10:41 PM 2/29/2000 -0800, Igor Kuznetsoff wrote: >>Daus, >> Please try to find out more about that >>acrylic/lead material, it sounds interesting. I >>figure on using an MDF/lead/MDF sandwich, with an >>additional layer of carbon fiber sheet if I can swing >>it. Glue between the MDF & lead will be Swedac, a >>pricey vibration damping glue. >> >> Igor > Subject: Re: [teres] Subchassis Design Layout Date: Fri, 3 Mar 2000 11:37:14 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; teres@aiko.com Igor, As far as I know there are only two ways to damp a structure. One is to use extensional damping by means of damping material firmly affixed to the structure by glueing, screws or rivets. And functions by the simple flexing of the damping material, which dissipates the vibrations to heat. The other is constained layer damping, which uses damping (sandwinch) material between two structues and has much higher loss due to the shear strain on the damping material when the stucture vibrates or flexes. So in order for CLD to function the damping material must be firmly glued to the structure, any shear strain (flex) on the glue and it becomes the damping material not the lead in your case. Of course maybe your using the lead as the structure, which is ok and a cool idea. Stan At 09:36 AM 3/2/2000 -0800, Igor Kuznetsoff wrote: >Stan, > Thanks for the analysis. I don't read it quite >the same way as you do, but am planning to do some >more testing. I have already played around with the >Swedac, with both 3/4" MDF & 1/8" "hardboard" panels. >"Hardboard" or "fiberboard"/pressed board-the stuff >that "peg board" is made of, only without the holes, >is a close relative of MDF, and has been around for as >long as I can remember, in 1/8 & 1/4" thicknesses. It >mimics the sonics of MDF, but, being thinner, is >noisier, if laminated in just two layers, making the >effects of a test lamination much easier to read/hear. >On the other hand, if you were to laminate 3 x 1/4" >with, say, the Swedac, the result would be *way* >quieter than 3/4" of MDF, and just as stiff! If you >also added something else, like carbon fiber... >Swedac dries, not cures, and dries very slowly if >bounded by materials that do not absorb any of its >solvent (water, so far as I know), and this may >account for it's use principally on wood. It acts much >like ordinary wood glues in this respect. Practically >speaking, at least one of the bonded materials would >have to be wood or fiber composite such as MDF, and >such a hybrid bond takes a long time to dry. I've >tried bonding acrylic to fiberboard with it, and the >bond is strong, but took forever, my objection to it. >I would not be concerned about "decoupling" the lead, >but would, rather, consider the Swedac an *additional* >constrained layer in its own right. Perhaps Daus, in >school for this very subject, if I got that right, >will comment on this. I plan to do some more testing >on various combinations, yet, using the (1/8") >fiberboard modeling technique first, then confirming >with MDF. > The isodamp sounds interesting, as all such >materials are to me, I will have to try it sometime. >I would be concerned about the strength of both its >bond, and the material itself (internally) within some >of the uses I could put it to. For this reason, and >others (such as a possible use on platters), the >thinner version is particularly attractive. >Specifically, if Manfred's new motor controller is >designed like the earlier one he transmitted (I sure >hope so, in this regard), it will require a strobe >readout bonded to the bottom of the platter. >(Manfred, or Chris, *does* it use that optical >pickup?) So long as this is so, it might as well be >bonded with some of this isodamp, no? > Thanks for reminding me of the new polyurethane >glues, I had noted to myself when I first heard of >them that I wanted to experiment with them, but forgot >all about it. An important factor in their use, as >just discussed, would be how they set/dry when bounded >by non-porous materials. Epoxy would work there, as >it catalyzes, not "dries", but I would like to find a >more compliant glue, not hard-to-brittleness like most >epoxies (with age), but with an equivalent strength. >Please don't suggest something like (ordinary) >Silicone, that is totally unsuitable. I do have a >two-part *catalyzed* silicone around, which I have >used to make flexible cable covers, and other flexible >coatings, and it is not only much tougher than the >ordinary squeeze tube/cartridge type silicone, but >also makes a very pretty, *smooth* coating on whatever >is dipped into it, or painted with it before it starts >to "kick" off. Additionally, it can be tinted any >color you like prior to catalyzing (naturally, it is a >slightly off-clear amber color). You can even mix in >particulants like metalflake if you wanted. Very >useful, and can be found in most art/drafting supply >type stores, in the resins/modeling clays department. >I might try a little (meaning a thin layer) of this to >see how it performs. Ordinary silicone has poor >internal self-damping characteristics, more like >hard-set jello wiggling about than what we need, and >weak, besides. > > Igor > >--- Stanley Goudge wrote: >> Igor , I think you need a tight coupling between the >> lead and MDF in order for the lead to damp. >> With the Swedac glue you may decouple the lead from >> the MDF because of its elasticity. I'd use >> epoxy or that new polyurethane stuff. Swedac glue is >> mainly used for laminating wood to wood. >> Or why not try the isodamp stuff I described >> earlier. Its the clostest thing to a "synthetic >> lead" and >> you just peal and stick it. And once its cured it >> ain't coming off! It can be orderd with both sides >> with >> PSA (pressure sensitive adhesive). >> >> Stan >> >> >> >> At 10:41 PM 2/29/2000 -0800, Igor Kuznetsoff wrote: >> >Daus, >> > Please try to find out more about that >> >acrylic/lead material, it sounds interesting. I >> >figure on using an MDF/lead/MDF sandwich, with an >> >additional layer of carbon fiber sheet if I can >> swing >> >it. Glue between the MDF & lead will be Swedac, a >> >pricey vibration damping glue. >> > >> > Igor >> >> >> >__________________________________________________ >Do You Yahoo!? >Talk to your friends online with Yahoo! Messenger. >http://im.yahoo.com > Subject: RE: [teres] Motor Kit Requisitioning Summary Date: Fri, 3 Mar 2000 12:49:37 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; teres@aiko.com; 'teres@aiko.com' Guys, I think its best to get this stuff with both sides peel and stick because you can have instant constrained layer damping simply by adding very thin aluminum (.005" to.010" ) to the other side, if you weren't going to use a sandwich. This gives a much higher loss than plane old extensional damping and you can aways just leave the plastic peel on. I plan on making a stencil of the strobe disk so I can paint it on the aluminum and have the CLD function too. Hey its Friday, Stan At 04:46 PM 3/2/2000 -0600, Stanley Goudge wrote: >Guys, > Heres an update on the isodamp, the stuff we want is the CN-12 (.122" thick) and >CN-38 (.355" thick). CN-06 no longer available. The C-2003 and C-1002 is the blue stuff >some of you seen or heard about. It has a wider effective temperature range 0 to 60 degree centigrade >which we don't need, and not has effective at normal temperatures as the CN-XX. >This stuff looks and feels like.....plastic lead. Let me know what you guys want and I''ll be glade to >order it. Remember its a 4 week lead on the CN-38. > >Thanks, >Stan > >CN-12 27" x 48" sheet one side peel and stick $56.73 ea. >CN-12 27" x 48" sheet both sides peel and stick $72.90 ea. >CN-12 1' x 1' tile one side peel and stick $5.64ea. > >CN-38 1' x 1' tile one side peel and stick $12.58ea. >CN-38 1' x 1' tile both sides peel and stick $15.16ea. > Subject: RE: [teres] Motor Kit Requisitioning Summary Date: Fri, 3 Mar 2000 13:03:48 -0700 From: Mackris, Thom G., Mackris, Thom G. To: 'teres@aiko.com' Good ideas, Stan. Do you have a deadline as far as ordering the Iso Damp? I've been overwhelmed and haven't had a chance to think about how much I want and in what thickness. I like the stencil thoughts too. This was bubbling in the lower reaches of my consciousness but hadn't quite surfaced. Cheers, Thom -----Original Message----- From: Stanley Goudge [mailto:sgoudge@cisco.com] Sent: Friday, March 03, 2000 11:43 AM To: teres@aiko.com; teres@aiko.com; 'teres@aiko.com' Subject: RE: [teres] Motor Kit Requisitioning Summary Guys, I think its best to get this stuff with both sides peel and stick because you can have instant constrained layer damping simply by adding very thin aluminum (.005" to.010" ) to the other side, if you weren't going to use a sandwich. This gives a much higher loss than plane old extensional damping and you can aways just leave the plastic peel on. I plan on making a stencil of the strobe disk so I can paint it on the aluminum and have the CLD function too. Hey its Friday, Stan At 04:46 PM 3/2/2000 -0600, Stanley Goudge wrote: >Guys, > Heres an update on the isodamp, the stuff we want is the CN-12 (.122" thick) and >CN-38 (.355" thick). CN-06 no longer available. The C-2003 and C-1002 is the blue stuff >some of you seen or heard about. It has a wider effective temperature range 0 to 60 degree centigrade >which we don't need, and not has effective at normal temperatures as the CN-XX. >This stuff looks and feels like.....plastic lead. Let me know what you guys want and I''ll be glade to >order it. Remember its a 4 week lead on the CN-38. > >Thanks, >Stan > >CN-12 27" x 48" sheet one side peel and stick $56.73 ea. >CN-12 27" x 48" sheet both sides peel and stick $72.90 ea. >CN-12 1' x 1' tile one side peel and stick $5.64ea. > >CN-38 1' x 1' tile one side peel and stick $12.58ea. >CN-38 1' x 1' tile both sides peel and stick $15.16ea. > Subject: RE: [teres] Motor Kit Requisitioning Summary Date: Fri, 3 Mar 2000 13:45:15 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; 'teres@aiko.com' Oh yea deadlines, so this is how things get done, was wondering why my boss always has deadlines and things do get done. But it never really sank in till now....umm I think I'm learning more from this list than from my boss. Ok lets say next Monday 3/13/00 @ noon. Thanks, Stan At 11:48 AM 3/3/2000 -0700, Mackris, Thom G. wrote: >Good ideas, Stan. > >Do you have a deadline as far as ordering the Iso Damp? I've been >overwhelmed and haven't had a chance to think about how much I want and in >what thickness. > >I like the stencil thoughts too. This was bubbling in the lower reaches of >my consciousness but hadn't quite surfaced. > >Cheers, >Thom > >-----Original Message----- >From: Stanley Goudge [mailto:sgoudge@cisco.com] >Sent: Friday, March 03, 2000 11:43 AM >To: teres@aiko.com; teres@aiko.com; 'teres@aiko.com' >Subject: RE: [teres] Motor Kit Requisitioning Summary > > >Guys, > I think its best to get this stuff with both sides peel and stick because >you can have instant >constrained layer damping simply by adding very thin aluminum (.005" to.010" >) to the other side, >if you weren't going to use a sandwich. This gives a much higher loss than >plane old extensional >damping and you can aways just leave the plastic peel on. I plan on making a >stencil of the strobe >disk so I can paint it on the aluminum and have the CLD function too. > >Hey its Friday, >Stan > > >At 04:46 PM 3/2/2000 -0600, Stanley Goudge wrote: >>Guys, >> Heres an update on the isodamp, the stuff we want is the CN-12 (.122" >thick) and >>CN-38 (.355" thick). CN-06 no longer available. The C-2003 and C-1002 is >the blue stuff >>some of you seen or heard about. It has a wider effective temperature range >0 to 60 degree centigrade >>which we don't need, and not has effective at normal temperatures as the >CN-XX. >>This stuff looks and feels like.....plastic lead. Let me know what you guys >want and I''ll be glade to >>order it. Remember its a 4 week lead on the CN-38. >> >>Thanks, >>Stan >> >>CN-12 27" x 48" sheet one side peel and stick $56.73 ea. >>CN-12 27" x 48" sheet both sides peel and stick $72.90 ea. >>CN-12 1' x 1' tile one side peel and stick $5.64ea. >> >>CN-38 1' x 1' tile one side peel and stick $12.58ea. >>CN-38 1' x 1' tile both sides peel and stick $15.16ea. >> > Subject: [teres] CN12 / Strobe Disk Date: Fri, 3 Mar 2000 19:37:51 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Stan, How are you going to make that stencil? It sounds like an excellent idea, and as I wrote someplace, seems like just the way to fasten the strobe disk. I suppose this stuff is too sticky to try as mat, no? Igor --- Stanley Goudge wrote: > Oh yea deadlines, so this is how things get done, > was wondering why my boss always has deadlines and > things > do get done. But it never really sank in till > now....umm I think I'm learning more from this list > than from my boss. > Ok lets say next Monday 3/13/00 @ noon. > > Thanks, > Stan > > > At 11:48 AM 3/3/2000 -0700, Mackris, Thom G. wrote: > >Good ideas, Stan. > > > >Do you have a deadline as far as ordering the Iso > Damp? I've been > >overwhelmed and haven't had a chance to think about > how much I want and in > >what thickness. > > > >I like the stencil thoughts too. This was bubbling > in the lower reaches of > >my consciousness but hadn't quite surfaced. > > > >Cheers, > >Thom > > > >-----Original Message----- > >From: Stanley Goudge [mailto:sgoudge@cisco.com] > >Sent: Friday, March 03, 2000 11:43 AM > >To: teres@aiko.com; teres@aiko.com; > 'teres@aiko.com' > >Subject: RE: [teres] Motor Kit Requisitioning > Summary > > > > > >Guys, > > I think its best to get this stuff with both > sides peel and stick because > >you can have instant > >constrained layer damping simply by adding very > thin aluminum (.005" to.010" > >) to the other side, > >if you weren't going to use a sandwich. This gives > a much higher loss than > >plane old extensional > >damping and you can aways just leave the plastic > peel on. I plan on making a > >stencil of the strobe > >disk so I can paint it on the aluminum and have the > CLD function too. > > > >Hey its Friday, > >Stan > > > > > >At 04:46 PM 3/2/2000 -0600, Stanley Goudge wrote: > >>Guys, > >> Heres an update on the isodamp, the stuff we > want is the CN-12 (.122" > >thick) and > >>CN-38 (.355" thick). CN-06 no longer available. > The C-2003 and C-1002 is > >the blue stuff > >>some of you seen or heard about. It has a wider > effective temperature range > >0 to 60 degree centigrade > >>which we don't need, and not has effective at > normal temperatures as the > >CN-XX. > >>This stuff looks and feels like.....plastic lead. > Let me know what you guys > >want and I''ll be glade to > >>order it. Remember its a 4 week lead on the CN-38. > >> > >>Thanks, > >>Stan > >> > >>CN-12 27" x 48" sheet one side peel and stick > $56.73 ea. > >>CN-12 27" x 48" sheet both sides peel and stick > $72.90 ea. > >>CN-12 1' x 1' tile one side peel and stick > $5.64ea. > >> > >>CN-38 1' x 1' tile one side peel and stick > $12.58ea. > >>CN-38 1' x 1' tile both sides peel and stick > $15.16ea. > >> > > > > __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com Subject: RE: [teres] Subchassis Design Layout - Isodamp Date: Fri, 3 Mar 2000 20:12:31 -0700 From: Igor Kuznetsoff, Igor Kuznetsoff To: teres@aiko.com Stan, Now you've got it! I consider MDF/lead/MDF bonded with Swedac to be a *five* layer sandwich with *three* active layers of damping, one of them, lead, being dual purpose-both structure & damping. The Swedac is not simply a glue! I suppose you've missed some stuff I wrote about "Zero Passband" tuning early on in the project (I'm sure Thom put it in the digests). The idea is to try, as much as is reasonable, to arrange more than one consecutive (or serial) damping tuning in a system, in order to approach a situation where the passbands involved are different enough that they mutually exclude transmission of *any* frequency. The idea may be Utopian, nothing works that perfectly, but it *can* do a heck of a good job of damping, better than a single passband damping system. Igor --- Stanley Goudge wrote: Igor, As far as I know there are only two ways to damp a structure. One is to use extensional damping by means of damping material firmly affixed to the structure by glueing, screws or rivets. And functions by the simple flexing of the damping material, which dissipates the vibrations to heat. The other is constained layer damping, which uses damping (sandwinch) material between two structues and has much higher loss due to the shear strain on the damping material when the stucture vibrates or flexes. So in order for CLD to function the damping material must be firmly glued to the structure, any shear strain (flex) on the glue and it becomes the damping material not the lead in your case. Of course maybe your using the lead as the structure, which is ok and a cool idea. Stan __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com Subject: Re: [teres] Motor Pod Date: Sat, 4 Mar 2000 07:54:30 -0700 From: Gary Bronner, Gary Bronner To: teres@aiko.com I'd like to mention a simpler motor pod arrangement that I'm using currently, that seems to work quite well. This is used with a Scheu motor in a custom built motor housing. The motor housing is built along the lines that Scott Fraser mentioned in earlier posts. Its a block of aluminum, with two chambers machined into it. These chambers are filled with oil/lead shot to provide damping. An aluminum top plate screws to the block and o-rings seal off the chambers to prevent leakage of oil. The motor is actually attached to the top plate. This makes for a fairly heavy and very dead motor, however it still needs some isolation from the platter. I wanted to be able to mount the motor pod directly on the turntable plinth, instead of the split idea posted on Chris Brady's website. Since the motor housing is reasonably massive, it turned out that it was not necessary to solidly attach it to the base. Instead it sits of a piece of sorbothane cut to the same size as the motor housing. Belt tensioning is accomplished by manually moving the entire motor housing until the tension feels right and then setting the motor in place. The sorbothane is sticky enough that it seems to hold everything in place. And it provides very good isolation so that any vibrations from the motor housing are not transmitted to the plinth. Since the motor and the platter are mounted on the same base, it insures good alignment between them. I think this actually accomplishs quite a few things people are looking for without all the complications. Comments? ---Gary Bronner ----- Original Message ----- From: "Jon Lane" To: Sent: Saturday, March 04, 2000 1:14 AM Subject: RE: [teres] Motor Pod > > > Peter, > > Does this help? (see below) > > > > Igor > > > Gentlemen, > > Respectfully, the pivoting motor assumes a round belt, > right? The geometry is compounded with this arrangement > making flat belts (magnetic tape) impossible to use. Such > belts will chafe the pulley and run against one or the other > rim depending on motor tilt. > > I've been taking the following as truths: > > 1. A slightly radiused pulley for self centering a flat > belt. > > 2. Solidly fixing the motor against as much mass as > possible. > > 3. Pursuant both of these, orienting the motor shaft > absolutely vertical with respect to the platter rim. > > From there, a variety of tensioning methods can be used from > merely sliding the motor base away from the platter to using > a idler. Investigations into instrumentation drives reveals > the latter is common - I'd intended to use it myself. A > spring-tensioned idler using a quiet rotating pulley would > be simple, cheap and effective. And self-tending. > > But tilting the motor from perfectly vertical eliminates the > flat belt option. Is the pulley design decided on at this > point? > > Jon lane > > Subject: Re: [teres] Motor Pod Date: Sat, 4 Mar 2000 08:07:50 -0700 From: MaughanAudio@aol.com, MaughanAudio@aol.com To: teres@aiko.com I also agree. It is critical that the perpendicular alignment of the pulley to the ribbon/belt is correct else the ribbon/belt would track off center. The fly line in a "V" groove would be advantageous for this reason. But with a ribbon, the tension can be reduced due to the greater area of contact. Subject: Re: [teres] Motor Pod Date: Sat, 4 Mar 2000 08:13:26 -0700 From: MaughanAudio@aol.com, MaughanAudio@aol.com To: teres@aiko.com The VCR idler is a good idea. To avoid the use of springs, a weight pulley arrangement would be practical. Subject: RE: [teres] Motor Pod Date: Sat, 4 Mar 2000 08:48:24 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > > Such belts > > ??? I must have been unclear. For reference, the preceding line included the words "flat belt"... > will chafe the pulley and run against one or the other > > ????? Again I've confused you Peter? Say it isn't so ;o) Having constructed my share of similar designs, all of them as far back as the early eighties, the notion of a radiused pulley is well known to me. Obviously, to work well and not stress the center of the belt, especially if the ever-popular flat, rigid belt is used (that is, tape of Mylar or Kapton) the radius needs be relatively large, compounding - as I thought I said quite clearly, Peter - the problem of centering the belt if the motor is designed to rock. NOT centering the belt has it then run the real risk if chafing the pulley in some way or actually striking one pulley rim or the other. Perhaps one of the mathematicians among us could calculate the resulting angle of operation by our motor shaft of presumably only 2.5" in length attempting to adjust what may be say, a half an inch of slop between the centers of the two rotating points. That angle will be large unless the motor is very, very close to the perfect distance from the spindle in the first place. "Then slide the motor away, Jon" I hear you saying. But you've found that an "imprecise" method, Peter. Idlers (whether "a" or "an") are universally used in highly precision tape drives throughout the instrumentation biz. Unless I miss my guess, we're in effect building an instrument with tape drive, are we not gentlemen? > > rim depending on motor tilt. > > I don't see any particular reason that the motor > couldn't be run vertically, > or close as dammit. Did you mean to type "dammit" here, Peter? Now I'm confused. > A small level placed against > the housing for initial > tensioning would be all that would be required to > get it vertical. I am > assuming a fairly hefty motor assembly here, that > would not tend to shift > upon tensioning. The amount of counterwight > tension, I suspect, would be at > most a few ounces, not enough to disturb a motor > assembly conceivably > weighing 20+ pounds. With the degree of precision guaranteed by 100% machined interfaces throughout the 'table, could a bubble lever be precise enough for use here? I see this as less precise than orienting the shaft absolutely vertical and incrementally moving the motor for perfect tension. The rest of the 'table universe seems happy with this... Or use a idling belt tensioner. Cheap, quiet, available, and again, universal. > > 2. Solidly fixing the motor against as much mass as > > possible. > > Upon reflection, I'm not sure fixing is > necessary. Mass would be important > no matter how you did it, though less so if your > mounting was rigid to a > massive subchassis or plinth. In the design of the Teres, there is a tremendous emphasis placed on damping the subchassis. Including actually considering making the chassis (that is, the mechanical loop between arm and spindle) lossy, a notion I personally do not agree with. This instinct is healthy, however, as it calls into focus the need to quiet things down before they intrude. I only ask that a Teres DIY'er only give enough attention to damping the only source of REAL noise in the entire system of any consequence - the motor - at least equal billing. Gentlemen, consider the reason air bearings work well (and I've built those too, despite their "lossy" interface). They isolate all environmental noise away from the critical assemblies, especially the motor's noise. If you really want to hear black, black backgrounds, listen to even the rudimentary Mapleknoll's with their air bearing platters and air bearing arms. As we've all said many times over, a primary reason the Teres is going to sound world-class is because of it's mass coupling. This benefit is brought about by the cost constraints we don't suffer from. Why short circuit that philosophy by cheapening the motor environment? > From there, a variety of tensioning methods can > be used from > > merely sliding the motor base away from the platter > > This, at first glance, is a rather imprecise and > non-repeatable way to go > about this. Why, Peter? > > to using a(n, sic) idler. > > An idler is otherwise a good idea, one that I > came up with independently of > all you other geniuses. But, and a Big But, it's > monkey motion and adds > complexity. Peter, it's a universal application in the instrumentation trades. Belt tensioners are a proven entity. > Like how do you tension the idler, > what idler bearing do you > use, how much potential noise/vibration/caca do > you potentially introduce > into the system with another rotating mass (no > matter how small (many folks > are putting mucho skull sweat into eliminating > ALL vibrations,)) what > contact surface with the belt will there be, > where do you put the idler and > can you tension it independently without another > ten pounds of hardware? Guys, we're talking a twenty pound, three inch platter here. And an absolutely state of the art drive system. I'm sure some of us can play with a simple belt tensioner that runs quietly enough for this app because it'll be under no adverse conditions whatsoever. And it's off the shelf. > The beauty of Igor's idea is its simplicity. > And, another thought, it also > affords the ability to move the motor assembly > around to an extent, should > this prove to be efficacious to the ridding of > nasties. A permanent mount > would be just that, and you live with whatever > bad judgement you made about > placement. Can you explain these "nasties" beforehand, Peter? It may be useful to the design process if we knew what we were tuning out. Jon Lane Subject: RE: [teres] Motor Pod Date: Sat, 4 Mar 2000 09:04:57 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > You were echoing my thoughts, Jon - getting the > vertical plane of the motor > shaft and the platter bearing perfectly parallel > appears as if it would be a > chore. Any thoughts on how this can be > accomplished without staying up > late? > > Thom Not to worry. 1. Such designs are rampant in drive systems. The belt will NOT migrate away from center even with a large 4" radius on pulley center. Extremely minor corrections using a trio of screws (again, the nearly universal convention in high-end tables) bring the belt to dead center. If my cheesy Linn can do it, Teres will have no problem. 2. With all other surfaces and interfaces machined to modern tolerances, this radius is the single only deviation from level/plumb/square/straight in the entire mechanism - just as it was intended to be. Rocking the motor is compounded by a number of excess variables, IMHO because the rock angle must be extremely limited. Basically, we need to first calculate _what_ scope you buy with _what_ angle. With an axis less than 3" long, the scope runs to perhaps only tenths of inches while meanwhile, the belt is happily heading over to one of the pulley rims. Unless of course, the belt is a cord. But then the radiused pulley must be discarded. Which direction are we headed in? Frankly, Thom, your slide idea is still one of my favorites. Both infinitely adjustable and without the trauma of moving the entire block or worrying about belt centering with a teetering motor shaft. If we're planning on a flat belt, I still vote it should be a rigid one. The group can buy endless, precision-made instrumentation-grade plastic drive belts for $30 each from the instrumentation biz who has a track record of millions of these in everything from aerospace to the nearest tape drive. Quiet, reliable, long-lasting, easily centered, strong. This belt type is a known quantity with the finest DIY and production tables using Mylar in the majority of cases. Our pulley is designed for this. Unless we consciously move away from flat belts, I'm very skeptical of intentionally introducing dimensional variables and non-rigid, non-damped support to the motor itself. Jon Lane Subject: RE: [teres] Motor Pod Date: Sat, 4 Mar 2000 09:13:17 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > Jon, I would add that you are assuming that the "flat > belt" area is, well, flat... But, it is *not*. > Remember, we designed a *convex* surface into it, > ostensibly for belt auto-centering, but this also > affords a few degree's grace to the verticality issue. Igor, my exact words were: "1. A slightly radiused pulley for self centering a flat belt." Jon Lane Subject: RE: [teres] Motor Pod Date: Sat, 4 Mar 2000 09:27:46 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com > -----Original Message----- > From: owner-teres@aiko.com > [mailto:owner-teres@aiko.com]On Behalf Of > Igor Kuznetsoff > Sent: Saturday, March 04, 2000 1:37 AM > To: teres@aiko.com > Subject: Re: [teres] Motor Pod > > Peter, > You've got it! > > Jon, I would add that you are assuming that the "flat > belt" area is, well, flat... But, it is *not*. > Remember, we designed a *convex* surface into it, > ostensibly for belt auto-centering, but this also > affords a few degree's grace to the verticality issue. Igor, I'd said: > > > I've been taking the following as truths: > > > > > > 1. A slightly radiused pulley for self centering > > a flat > > > belt. My concern is that those of us using flat plastic belts (quieter than grooved pulleys running round belts, I presume) is that they are in fact, rigid. They will protest in some minute way any nonlinearity in their environment such as a non-parallel pulley side brought about by a tilted shaft. No, I'm going to fashion either a means of (1) incrementally scooting the motor fore or aft using a variant of Thom's motor track - itself a brilliant solution, I think - or, (2) a belt tensioning idler close to the motor pulley and attached to the motor block. And I intend to make the baddest motor block I can possible dream up but I will absolutely not remove it from perfect alignment with the platter aside from the tiniest adjustment via a trio of mounting screws surrounding the motor. I hope to use a solid 2" base and similarly designed motor pod right next door. Both sited on a paper-thin damping sheet on flat granite. Jon Lane Subject: Re: [teres] Motor Pod Date: Sat, 4 Mar 2000 11:41:05 -0700 From: phclark, phclark To: teres@aiko.com Jon, I'm not trying to be difficult here. I was hurtling down precisely the path you are choosing before Igor threw a monkey wrench in that thinking and proposed what I thought to be some thing worth serious consideration. As I said at the time, "Sho' looks Odd." This whole thing will probably get down to a differing philosophy thing, and maybe Igor and I will be the only ones to try his idea... Apart from the potential waste of time pursuing Igor's path, an advantage is no harm, no foul if it doesn't work. No hole drilled in the wrong places, etc., etc. If it doesn't work, try a more "conventional" method. I had certain concern that Igor's idea be explored without being dismissed out of hand. So far, the only issue that seems to be relevant is the "verticality." If implemented properly, Igor's idea makes the whole notion of an idler or other tensioner unnecessary, a worthy goal in my estimation. His "two point" mount is entirely passive in operation, no moving parts. As far as verticality is concerned, the addition of a third "foot" on the bottom of the motor pod oriented away from the axis of platter rotation would do the trick for initial positioning. It ought to be easy enough to get the length of the third foot to orient the whole pod within degrees of vertical before tensioning. (Actually, a fourth might not be a bad idea, allowing the pod to "rock" ever so slightly on the two business feet, the other two preventing it from falling over.) Upon tensioning, the third foot is "lifted"so it doesn't have contact, e voila. This could be done to first "balance" the pod, no load so to speak, before adjusting the weight position by use of the trusty spring gauge for tension. > > > Such belts > > > > ??? > > I must have been unclear. For reference, the preceding line > included the words "flat belt"... > > > will chafe the pulley and run against one or the other > > > > ????? > I was confused by "belts." I had supposed using only one. > Again I've confused you Peter? Say it isn't so ;o) > > Having constructed my share of similar designs, all of them > as far back as the early eighties, the notion of a radiused > pulley is well known to me. Obviously, to work well and not > stress the center of the belt, especially if the > ever-popular flat, rigid belt is used (that is, tape of > Mylar or Kapton) the radius needs be relatively large, > compounding - as I thought I said quite clearly, Peter - the > problem of centering the belt if the motor is designed to > rock. NOT centering the belt has it then run the real risk > if chafing the pulley in some way or actually striking one > pulley rim or the other. Perhaps one of the mathematicians > among us could calculate the resulting angle of operation by > our motor shaft of presumably only 2.5" in length attempting > to adjust what may be say, a half an inch of slop between > the centers of the two rotating points. That angle will be > large unless the motor is very, very close to the perfect > distance from the spindle in the first place. "Then slide > the motor away, Jon" I hear you saying. But you've found > that an "imprecise" method, Peter. Not really, the act of sliding doesn't tension the belt, adjustment of the weight does. That's precise. > Idlers (whether "a" or "an") are universally used in highly > precision tape drives throughout the instrumentation biz. > Unless I miss my guess, we're in effect building an > instrument with tape drive, are we not gentlemen? Again, I don't have any particular problem with idlers. I was intending to use one myself before Igor came along. The difficulty arises from their implementation in the spirit of practicality and KISS. As I've often said about coupling capacitors, "no mechanical monkey motion (or capacitor) is better than the best you can buy." > > > rim depending on motor tilt. > > > > I don't see any particular reason that the motor > > couldn't be run vertically, > > or close as dammit. > > Did you mean to type "dammit" here, Peter? Now I'm > confused. This means, "oh damn, just missed it." > > A small level placed against > > the housing for initial > > tensioning would be all that would be required to > > get it vertical. I am > > assuming a fairly hefty motor assembly here, that > > would not tend to shift > > upon tensioning. The amount of counterwight > > tension, I suspect, would be at > > most a few ounces, not enough to disturb a motor > > assembly conceivably > > weighing 20+ pounds. See comments above. > With the degree of precision guaranteed by 100% machined > interfaces throughout the 'table, could a bubble lever be > precise enough for use here? I see this as less precise > than orienting the shaft absolutely vertical and > incrementally moving the motor for perfect tension. The > rest of the 'table universe seems happy with this... Or use > a idling belt tensioner. Cheap, quiet, available, and > again, universal. > > > > 2. Solidly fixing the motor against as much mass as > > > possible. > > > > Upon reflection, I'm not sure fixing is > > necessary. Mass would be important > > no matter how you did it, though less so if your > > mounting was rigid to a > > massive subchassis or plinth. > > In the design of the Teres, there is a tremendous emphasis > placed on damping the subchassis. Including actually > considering making the chassis (that is, the mechanical loop > between arm and spindle) lossy, a notion I personally do not > agree with. This instinct is healthy, however, as it calls > into focus the need to quiet things down before they > intrude. This is a related but separate subject. I am graced with concrete floors and certain considerations for other Teres listees possibly don't apply to my installation. My intent is to try using a massive plinth (135# machinists' surface plate) only to start, with separate subchassis for motor, platter and arm. On a concrete floor this might prove to be sufficient without complexifying. I always have the option to add sand boxes and inner tubes should the initial installation prove unsatisfactory > I only ask that a Teres DIY'er only give enough attention to > damping the only source of REAL noise in the entire system > of any consequence - the motor - at least equal billing. > Gentlemen, consider the reason air bearings work well (and > I've built those too, despite their "lossy" interface). > They isolate all environmental noise away from the critical > assemblies, especially the motor's noise. If you really > want to hear black, black backgrounds, listen to even the > rudimentary Mapleknoll's with their air bearing platters and > air bearing arms. > > As we've all said many times over, a primary reason the > Teres is going to sound world-class is because of it's mass > coupling. This benefit is brought about by the cost > constraints we don't suffer from. Why short circuit that > philosophy by cheapening the motor environment? I agree. And if Igor's idea doesn't pan out, it won't be the first time some only flew on paper. > > From there, a variety of tensioning methods can > > be used from > > > merely sliding the motor base away from the platter > > > > This, at first glance, is a rather imprecise and > > non-repeatable way to go > > about this. > > Why, Peter? > > > > to using a(n, sic) idler. > > > > An idler is otherwise a good idea, one that I > > came up with independently of > > all you other geniuses. But, and a Big But, it's > > monkey motion and adds > > complexity. > > Peter, it's a universal application in the instrumentation > trades. Belt tensioners are a proven entity. Absolutely. Again, I'm not saying it wouldn't work or that the application is not common. Igor's Two Point Mount is, OTOH, purpose built for a specific application, to solve a particular problem. Instrumentation applications are built in one location and have to survive the trip to point of use intact with repeatable results. Not dissimilar to building a portable hydroelectric dam. That is not true here. If it works, you only do it once per installation and can implement it to optimize results. > > Like how do you tension the idler, > > what idler bearing do you > > use, how much potential noise/vibration/caca do > > you potentially introduce > > into the system with another rotating mass (no > > matter how small (many folks > > are putting mucho skull sweat into eliminating > > ALL vibrations,)) what > > contact surface with the belt will there be, > > where do you put the idler and > > can you tension it independently without another > > ten pounds of hardware? > > Guys, we're talking a twenty pound, three inch platter here. > And an absolutely state of the art drive system. I'm sure > some of us can play with a simple belt tensioner that runs > quietly enough for this app because it'll be under no > adverse conditions whatsoever. And it's off the shelf. > > > The beauty of Igor's idea is its simplicity. > > And, another thought, it also > > affords the ability to move the motor assembly > > around to an extent, should > > this prove to be efficacious to the ridding of > > nasties. A permanent mount > > would be just that, and you live with whatever > > bad judgement you made about > > placement. > > Can you explain these "nasties" beforehand, Peter? It may > be useful to the design process if we knew what we were > tuning out. Unanticipated resonances elsewhere in the system... Again, I'm not trying to be argumentative. Assuming that the motor is as quiet as we can procure, and that the assembly is sufficiently massive to damp the remaining nasty, utilization of the simplest tensioning method would seem to be the path to follow. If it doesn't work, go to Plan B. Cheers, Peter C Subject: Re: [teres] Motor Pod Date: Sat, 4 Mar 2000 11:44:22 -0700 From: phclark, phclark To: teres@aiko.com Sounds workable to me. Sorbothane is great stuff. The potential difficulty of maintaining repeatable belt tension remains, it seems to me. Peter C ----- Original Message ----- From: "Gary Bronner" To: Sent: Saturday, March 04, 2000 6:53 AM Subject: Re: [teres] Motor Pod > I'd like to mention a simpler motor pod arrangement that I'm using > currently, that seems to work quite well. This is used with a Scheu motor > in a custom built motor housing. The motor housing is built along the lines > that Scott Fraser mentioned in earlier posts. Its a block of aluminum, with > two chambers machined into it. These chambers are filled with oil/lead shot > to provide damping. An aluminum top plate screws to the block and o-rings > seal off the chambers to prevent leakage of oil. The motor is actually > attached to the top plate. This makes for a fairly heavy and very dead > motor, however it still needs some isolation from the platter. > I wanted to be able to mount the motor pod directly on the turntable plinth, > instead of the split idea posted on Chris Brady's website. Since the motor > housing is reasonably massive, it turned out that it was not necessary to > solidly attach it to the base. Instead it sits of a piece of sorbothane cut > to the same size as the motor housing. Belt tensioning is accomplished by > manually moving the entire motor housing until the tension feels right and > then setting the motor in place. The sorbothane is sticky enough that it > seems to hold everything in place. And it provides very good isolation so > that any vibrations from the motor housing are not transmitted to the > plinth. Since the motor and the platter are mounted on the same base, it > insures good alignment between them. > I think this actually accomplishs quite a few things people are looking for > without all the complications. Comments? > > ---Gary Bronner > ----- Original Message ----- > From: "Jon Lane" > To: > Sent: Saturday, March 04, 2000 1:14 AM > Subject: RE: [teres] Motor Pod > > > > > > > Peter, > > > Does this help? (see below) > > > > > > Igor > > > > > > Gentlemen, > > > > Respectfully, the pivoting motor assumes a round belt, > > right? The geometry is compounded with this arrangement > > making flat belts (magnetic tape) impossible to use. Such > > belts will chafe the pulley and run against one or the other > > rim depending on motor tilt. > > > > I've been taking the following as truths: > > > > 1. A slightly radiused pulley for self centering a flat > > belt. > > > > 2. Solidly fixing the motor against as much mass as > > possible. > > > > 3. Pursuant both of these, orienting the motor shaft > > absolutely vertical with respect to the platter rim. > > > > From there, a variety of tensioning methods can be used from > > merely sliding the motor base away from the platter to using > > a idler. Investigations into instrumentation drives reveals > > the latter is common - I'd intended to use it myself. A > > spring-tensioned idler using a quiet rotating pulley would > > be simple, cheap and effective. And self-tending. > > > > But tilting the motor from perfectly vertical eliminates the > > flat belt option. Is the pulley design decided on at this > > point? > > > > Jon lane > > > > > > Subject: RE: [teres] Motor Pod Date: Sat, 4 Mar 2000 15:16:55 -0700 From: Jon Lane, Jon Lane To: teres@aiko.com Peter said, > I'm not trying to be difficult here. I was > hurtling down precisely the path > you are choosing before Igor threw a monkey > wrench in that thinking and > proposed what I thought to be some thing worth > serious consideration. As I > said at the time, "Sho' looks Odd." This whole > thing will probably get down > to a differing philosophy thing, and maybe Igor > and I will be the only ones > to try his idea... > > Apart from the potential waste of time pursuing > Igor's path, an advantage is > no harm, no foul if it doesn't work. No hole > drilled in the wrong places, > etc., etc. If it doesn't work, try a more > "conventional" method. > > I had certain concern that Igor's idea be > explored without being dismissed > out of hand. So far, the only issue that seems > to be relevant is the > "verticality." If implemented properly, Igor's > idea makes the whole notion > of an idler or other tensioner unnecessary, a > worthy goal in my estimation. > His "two point" mount is entirely passive in > operation, no moving parts. And I want to be clear that this idea has its obvious merits: The belt is under constant tension and with an adjustable, yet invariable as standard to work from. Gravity. The notion is VERY attractive provided all of the designed elements are balanced, IMHO. Two impractical sides to this, as I see them in my limited perspective. 1. The belt _will_ chafe if the pulley is in anything other than perfect upright alignment. Assuming a radiused pulley - and we are, right? - the pulley surface will scribe infinite and ever so slight arcs against the driven surface of the belt when the motor is tipped off axis. Yes, the belt will center around some portion of this "ball" at the end of the motor shaft, but intuitively, the drive will be in a constant state of imperceptible friction. Noise? Theoretically, yes. How much? Don't know. Audible? Don't know again. 2. With a motor _not_ in firm contact with its independent chassis, any cogging (Manfred?) that may be present will work against the compliant mounting. Again perhaps completely imperceptibly, the motor will shudder constantly during operation unless it's rigidly fixed. Now this, in my mind, raises another point. If the motor _is_ bolted securely into another twenty pounds of housing, will any of this theoretical cogging make its way into the drive, not being able to go anywhere else? Seems to me a balance needs to be struck. Time to consult the motor experts in attendance. I hasten to add my disclaimer which is that I have always avoided compliant interfaces in any transducer system. I do not use rubber mountings for my drivers in spite of their obvious damping because such resilient interfaces introduce another resonant mechanism entirely - they may eliminate say, HF resonance, but they must impart, by nature, a predominant LF fundamental in it's place. Might the same happen with a resilient motor mounting? An entire spectrum of upper harmonics are attenuated to the degree that any such damped mounting can, but a new and pronounced resonance (vibration, actually) is introduced where the suspended weight, cogging speed (if any) and resilient Q all interact. If this is correct (correct me; this is speculation!) than would we be better served by a rigid, dead-vertical motor environment? If so, how do we tension the belt? This major problem remains. Personally, I believe miniature belt tensioners are perfectly suitable. These have justifiably been brought into question, however for reasons of being, we assume, noisy. Okay, I'd suggest "sledding" the entire motor housing. That is, allowing it to float to and fro in one plane only against one intentional constant; either a spring set or Igor's elegant weight. What are the benefits I see here? 1. Perfect alignment between platter and pulley. 2. An as-specified environment for the flat, rigid belt to live in. It will simply seek its own position related only to the pulley radius and will be driven dead parallel to it's center line. As before, the platter end will follow suit. 3. Thusly, near-zero out-of-alignment condition to create chafing against the radiused pulley. The "quietest" possible drive, assuming this is desirable. 4. While I don't feel belt wear is really a practical issue, we can take this one step further and reduce the pulley to a flat design just as is typically done in tape drives. Or perhaps a really huge radius like a half a foot or so. This drives the belt uniformly across its entire surface, or in the case of the large radius option, at least in the way least destructive to the belt's shape. Mylar and Kapton hate to stretch. > Not really, the act of sliding doesn't tension > the belt, adjustment of the > weight does. That's precise. But sliding on a design intended for the purpose would be perhaps the best solution. And one completely unique to Teres which I really like. No other 'table regardless of cost or rated excellence to my knowledge uses a movable motor sled with a tensioning constant like gravity or, to a lesser degree, a set of springs. Let's hang it out there! > Again, I don't have any particular problem with > idlers. I was intending to > use one myself before Igor came along. The > difficulty arises from their > implementation in the spirit of practicality and > KISS. As I've often said > about coupling capacitors, "no mechanical monkey > motion (or capacitor) is > better than the best you can buy." True, but I'd ask that we isolate the complexity of performing a simple task from the simplicity of the task itself. Frankly, excepting the presumed costs involved, I'd wager that "sledding" the entire motor against a gravity constant is actually far simpler in _function_ and use than attempting to orient a motor in a geometrically variable environment. > This is a related but separate subject. I am > graced with concrete floors > and certain considerations for other Teres > listees possibly don't apply to > my installation. My intent is to try using a > massive plinth (135# > machinists' surface plate) only to start, with > separate subchassis for > motor, platter and arm. On a concrete floor this > might prove to be > sufficient without complexifying. I always have > the option to add sand > boxes and inner tubes should the initial > installation prove unsatisfactory With exception to isolating the arm, I'm dead parallel with you here Peter. Mine and yours are going to have many resemblances... > Unanticipated resonances elsewhere in the system... Agreed. Smart variables built in at the right places are a godsend when it comes time to dial in. The difference between fabulous sound and transcendent sound is usually found in those adjustments, IME. > Again, I'm not trying to be argumentative. Not taken that way, sir. Your passion is why this project is working! > Assuming that the motor is as > quiet as we can procure, and that the assembly is > sufficiently massive to > damp the remaining nasty, utilization of the > simplest tensioning method > would seem to be the path to follow. If it > doesn't work, go to Plan B. I'm going to slide my entire motor... Complex, but simple, if you catch my meaning. Jon Lane Subject: [teres] Motor Orientation Date: Sat, 4 Mar 2000 15:36:27 -0700 From: Jon Lane, Jon Lane To: Teres@Aiko.Com Gentlemen, In discussing our need to tension the belt against drive and driven surfaces alike, I suggested we take a cue from those who have gone before us and drive the belt dead on axis with the platter. Doing so, I argued, created an environment least hostile to the belt and ensured that it lived a long and quiet life. But how we would tension was left more or less unanswered. Given the latitude we've given ourselves in everything from the platter to bearing to bases to motor and controller, we have set a consistently high goal for all elements thus far. And I think one of remarkable continuity - Teres has neither weak links or excesses at this point. All components are equally well done but none are outrageously so. So I ask your opinion of this, which I think is also consistent with our efforts to this point: Consider that the machine industry uses what are called linear bearings (apologies to those already knowing this, you are indeed many) which are intended to allow very precise motion along one axis, say, a machine table motion across a bed. These bearings may use captured stainless balls or lubricated sleeves against precision ground steel rods to allow, as I said, one-axis motion. Obviously we're not interested in motion, per se, just a bit of flexibility to allow precise, invariable tensioning against the belt. Our givens are these: 1. We need tensioning. 2. We don't want it to be ham-fisted or crude. No sliding 20 lbs of aluminum about. It must be elegant and precise because Teres is. And repeatable, and dependable. 3. Linear bearings come in absolutely all sizes and designs, and they are off the shelf and relatively inexpensive. Therefore, how's about we institute a pair of miniature linear bearings to hold our various motor housings upright and rigid and then simply add either a soft spring between motor housing and platter base, or fab up a little weight and bracket to work tension? From there, the motor seeks just the right position (working against an adjustable constant in either case) thus tensioning the belt to perfection. And the linear ways look cool, too. In the tool and die industry are found tiny sleeves with lubrication or miniature stainless bearings throughout their length and diameter. These ride on common stainless rods. A bit of machining to accept this in the motor housing and a complimentary fixture to bolt the rods to just so and we're done. This stuff is already on the shelf. Anybody? We're talking maybe a hundred bucks complete. Jon Lane Subject: Re: [teres] Motor Pod Date: Sat, 4 Mar 2000 16:09:06 -0700 From: Steve Zettel, Steve Zettel To: teres@aiko.com Peter, Jon, and Gary all raise interesting concerns about motor mounting and belt tensioning. I suspect I will probably start my implementation from simplest and work to more complex if that proves less than satisfactory. Most likely Gary's or Igor's idea. The only fly I see in the ointment regarding separate motor and turntable subchassis in a sandbox, is keeping the motor aligned and stationary relative to the turntable subchassis. A very thin sorbothane pad under the motor pod MAY also form an energy storage system or allow some repetitive relative motion between motor and platter. The concern we have had with spring tensioning via an idler is the introduction of the very vibrations, at some resonant frequency, we are seeking to eliminate. A weight providing the tension for an idler would seem less likely to set up an energy storage and release system than a spring. Eliminating the idler, and allowing the weight of the motor/pod provide the tension, eliminates one more potential source of mechanical vibrations -- imprecision in the idler bearings, any run-out in the circumference of the idler surface, any inaccuracy in aligning the idler axis vertically with the other axis'. I am a real believer in eliminating all that is not absolutely necessary to the function of the mechanism. With elimination of the idler, we eliminate a host of complexities and potential inaccuracies. When analyzing the total accuracy of a system, each variable's worst case tolerance is additive. We have gone to great trouble to procure the most precise bearing/spindle/platter assembly within our budget including having them all machined by the same source. If we add an idler, even one as finely machined and precise as our bearing, we are still adding all of it's worst-case tolerances to that of our turntable (idler run-out to turntable platter and bearing run-out, idler wobble to platter and bearing wobble, vibrational excursions, harmonic frequencies, etc, etc). As someone else said, there is no capacitor as good as no capacitor. It may well end up that something more complex DOES become the best solution to our problem, just as sometimes there is no escaping the need for a capacitor. However, I'll treat that necessity if it becomes apparent. The beauty of this project is that we still have an incredible flexibility in each of our implementations. I want to keep hearing about everyone's analysis of problems and methods of addressing them, it helps me to prioritize and gain perspective -- and not forget something basic. And often someone comes up with a much better implementation or solution than I would ever have thought of on my own. Steve Z near Libby, MT USA Subject: RE: [teres] Subchassis Design Layout - Isodamp Date: Sat, 4 Mar 2000 16:42:19 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; teres@aiko.com Igor, I'm still not sure, because what I mean by structure is the part that contacts the item your trying to isolate. In this case the turntable or was this a subchassis design, in this case the spindle/bearing would contact the lead only. Have you tried lead/MDF/MDF,where the lead is the top surface. Maybe a thick slab of lead say 1/4" with the next layers MDF/HDF. But I think the ultimate base or subchassis material is a stainless steel sandwich SS/CN/SS. In fact SS/CN/SS should be first choice, whether it be a platter,subchassis, motor mount, motor pod, stand and base. Because SS combines high stiffness to weight ratio with self damping qualities that no other material has. Why do you think most mega buck TT that we'll never hear, use the hell out it, unfortunately thats why they costs mega bucks. Its tough & expensive stuff to machine, which should tell you something right there about its ideal rigid body qualities. My second choice would be aluminum, because its cheap and easy to machine and there are many grades like 7075 which is pretty stiff stuff, combined with softer aluminums or even SS in a sandwich with CLD gives an excellent alternative to the mega buck SS. My third choice is anything I can cut or fab on my table saw or router, but these materials usually just don't cut it. Have fun, Stan P.S. Swedac I think is PVA, used to damp dome tweeters. I have both in hand and can't tell the difference when dry. At 06:09 PM 3/3/2000 -0800, Igor Kuznetsoff wrote: >Stan, > Now you've got it! I consider MDF/lead/MDF >bonded with Swedac to be a *five* layer sandwich with >*three* active layers of damping, one of them, lead, >being dual purpose-both structure & damping. The >Swedac is not simply a glue! I suppose you've missed >some stuff I wrote about "Zero Passband" tuning early >on in the project (I'm sure Thom put it in the >digests). The idea is to try, as much as is >reasonable, to arrange more than one consecutive (or >serial) damping tuning in a system, in order to >approach a situation where the passbands involved are >different enough that they mutually exclude >transmission of *any* frequency. The idea may be >Utopian, nothing works that perfectly, but it *can* >do a heck of a good job of damping, better than a >single passband damping system. > > Igor > >--- Stanley Goudge wrote: > >Igor, > As far as I know there are only two ways to damp >a structure. >One is to use extensional damping by means of damping >material firmly >affixed to the structure >by glueing, screws or rivets. And functions by the >simple flexing of >the >damping material, which dissipates the >vibrations to heat. The other is constained layer >damping, which uses >damping (sandwinch) material between >two structues and has much higher loss due to the >shear strain on the >damping material when the stucture vibrates >or flexes. So in order for CLD to function the damping >material must be >firmly glued to the structure, any shear strain (flex) >on the glue and it becomes the damping material not >the lead in your >case. >Of course maybe your using the lead >as the structure, which is ok and a cool idea. > >Stan > >__________________________________________________ >Do You Yahoo!? >Talk to your friends online with Yahoo! Messenger. >http://im.yahoo.com > Subject: Re: [teres] Motor Pod Date: Sat, 4 Mar 2000 16:51:55 -0700 From: Stanley Goudge, Stanley Goudge To: teres@aiko.com; teres@aiko.com Good idea Igor, now move the two point to the right and you can eliminate the extra weights. Stan At 07:46 PM 3/3/2000 -0800, Igor Kuznetsoff wrote: >Peter, > Does this help? (see below) > > Igor > > >--- phclark wrote: >> This has some merit, though I confess it sounds a >> little Heath Robinson. >> Perhaps you could flesh this out with some drawings? >> >> Peter C >> >> >> ----- Original Message ----- >> From: "Igor Kuznetsoff" >> To: >> Sent: Tuesday, February 29, 2000 2:01 PM >> Subject: Re: [teres] Motor Pod >> >> >> > All, >> > Following the various factors & solutions >> > discussed pertaining to motor pod design & >> > implementation, I had yet another thought for >> > consideration. I suppose some of you wish I would >> run >> > out of them by now, but I can't help it. This >> > concerns the underpinnings of the pod. While I am >> > sure that we will end up with a variety of >> techniques >> > employed, I would like to suggest a novel >> > configuration which would probably not normally be >> > considered. >> > What I have in mind is pursuant to my >> previous >> > suggestion that there should be enough compliance >> in >> > the motor/platter axis to allow a belt tensioning >> > scheme to do its thing unhindered, so that it can >> be >> > repeatably calibrateable. My suggestion today is >> to >> > place the motor pod on two, yes two, not three >> (much >> > less four) cones. >> > [Double your pleasure/Double your fun/with two >> cones, >> > yes *two* cones on one.(axis) (viz. : Pretty twins >> > holding two motor pods) ] >> > Wouldn't this just fall over? Well, yes, if you >> tried >> > to stand this up by itself. To this end , >> something >> > like slightly shorter "training wheel" feet of >> some >> > sort could be added on the cross-axis, for >> convenience >> > during setup, or disuse. If, however, in use, >> this >> > was balanced (adding a simple, inexpensive bubble >> > level to the top of the pod would be a good idea), >> and >> > the belt slipped on, and the belt tensioning set, >> this >> > rig will stand up nicely, and, this being the >> > important thing, *belt tension will now be >> dependent >> > only on the tensioner setting*. Additionally, >> > concentrating the weight upon just two cone >> points, >> > not three or more, couples the pod to the surface >> it >> > sits on even better. Should you not want this >> tight >> > coupling to implement your personal technical >> > philosophy, or layout combinations, just use >> something >> > compliant instead of the two cones. Finding the >> > balance points for placing the cones is simple >> enough. >> > If your pod is symmetrical, this is obvious, just >> use >> > the centerline. If it is not , due to the layout >> of >> > switches, power supply, whatever, just set the >> > completed pod, minus the balancing weight (if you >> go >> > that route, which I suspect would be the most >> popular >> > for its simple neatness, not mention the >> adaptability >> > of old tonearms & their weights) on a dowel or >> > something like that along the expected balance >> axis. >> > play with it until it balances neatly, mark the >> > location, & mount the cones, or whatever, on that >> > line. I would suggest exiting the wiring on the >> > centerline somewhere to maintain balance. >> > To sum up what could be the ideal pod >> setup: >> > The scheme outlined above, a belt tensioner rig, a >> > voltmeter for setting the actual tension, a >> rotateable >> > motor mounting plate, a massive pod designed to >> > dissipate vibration, and a lightweight metal >> pulley >> > with dual profiles. The belt, if flat, should >> have a >> > half twist. Feel free to add anything I've left >> out. >> > A thought about using the voltmeter might be >> > worthwhile at this point. As the idea has been >> > running so far, it is assumed that the lowest >> voltage >> > reading would correlate to the lowest tension >> useable, >> > and that would be the ideal setting for belt >> tension. >> > I disagree with that. I suspect that at that >> lowest >> > tension we would be running at the onset of >> slippage, >> > which would be very difficult to determine, >> quantify, >> > or even pin down sonically by ear, and this would >> be >> > an unwise condition. I posit that it would be a >> > better regimen to find that lowest point, and >> increase >> > tension bias to just a bit above that to guarantee >> the >> > smoothest power transfer. >> > >> > Igor >> > >> > >> > __________________________________________________ >> > Do You Yahoo!? >> > Talk to your friends online with Yahoo! Messenger. >> > http://im.yahoo.com >> > >> >> >__________________________________________________ >Do You Yahoo!? >Talk to your friends online with Yahoo! Messenger. >http://im.yahoo.com > Subject: Re: [teres] Motor Orientation Date: Sat, 4 Mar 2000 19:14:42 -0700 From: phclark, phclark To: teres@aiko.com Jon, This also has merit. I guess my principal objection is to the idler, which, while it will do the job, it also can/will add variables we are striving mightily to eliminate. A track system utilizing passive weight for tensioning has big possibility, though it is more complex than Igor's idea. Should we decide collectively to go down this path, it would require, however, almost as much thought as the rest, plus a bunch of fabrication. Perhaps others have given tracks, etc. more thought? Peter C ----- Original Message ----- From: "Jon Lane" To: "Teres@Aiko.Com" Sent: Saturday, March 04, 2000 2:32 PM Subject: [teres] Motor Orientation > Gentlemen, > > In discussing our need to tension the belt against drive and > driven surfaces alike, I suggested we take a cue from those > who have gone before us and drive the belt dead on axis with > the platter. Doing so, I argued, created an environment > least hostile to the belt and ensured that it lived a long > and quiet life. > > But how we would tension was left more or less unanswered. > Given the latitude we've given ourselves in everything from > the platter to bearing to bases to motor and controller, we > have set a consistently high goal for all elements thus far. > And I think one of remarkable continuity - Teres has neither > weak links or excesses at this point. All components are > equally well done but none are outrageously so. So I ask > your opinion of this, which I think is also consistent with > our efforts to this point: > > Consider that the machine industry uses what are called > linear bearings (apologies to those already knowing this, > you are indeed many) which are intended to allow very > precise motion along one axis, say, a machine table motion > across a bed. These bearings may use captured stainless > balls or lubricated sleeves against precision ground steel > rods to allow, as I said, one-axis motion. Obviously we're > not interested in motion, per se, just a bit of flexibility > to allow precise, invariable tensioning against the belt. > > Our givens are these: > > 1. We need tensioning. > 2. We don't want it to be ham-fisted or crude. No sliding > 20 lbs of aluminum about. It must be elegant and precise > because Teres is. And repeatable, and dependable. > 3. Linear bearings come in absolutely all sizes and > designs, and they are off the shelf and relatively > inexpensive. > > Therefore, how's about we institute a pair of miniature > linear bearings to hold our various motor housings upright > and rigid and then simply add either a soft spring between > motor housing and platter base, or fab up a little weight > and bracket to work tension? From there, the motor seeks > just the right position (working against an adjustable > constant in either case) thus tensioning the belt to > perfection. And the linear ways look cool, too. > > In the tool and die industry are found tiny sleeves with > lubrication or miniature stainless bearings throughout their > length and diameter. These ride on common stainless rods. > A bit of machining to accept this in the motor housing and a > complimentary fixture to bolt the rods to just so and we're > done. This stuff is already on the shelf. Anybody? We're > talking maybe a hundred bucks complete. > > Jon Lane > > >