[Editor's note .... This first digest on the motor and power supply contains mostly idle musings about where the project will go. It is primarily of historic interest rather than conatining substantive information about where the controller design would eventually end up. Some surplus DC motors were sourced and were intended for use in the first iteration of the turntable. Subsequent to that, Manfred Huber and Allen Wright offered their design services. Manfred had designed an intelligent controller for his = Thomas Scheu turntable and agreed to adapt the micro code for use in this project. The primary focus in the period from mid December, 1999 through the end of January, 2000 was the design of the bearing and platter. Subsequent digests will have more "serious" commentary, especially after Manfred appeared on the scene. The next digest begin's with Manfred's announcement ] ----- Original Message ----- From: Schei, Kenneth Sent: Thursday, December 16, 1999 11:43 PM Subject: Scheu-Motor Guys: I'd like to contribute my thoughts (and expertise) to the power supply question. As a serious model railroader, I've experimented quite a lot with high-quality electric moters and power supplies. The motors I'm thinking of are not trivial. They are Swiss Falhaber instrument motors which cost upwards of $100. However I have occasionally found them at Gateway and other surplus stores for a fraction of that price. I have a small = stash of them. They are extremely high quality (read "quiet") 12 VDC (read "quiet") motors. They are extremely high efficiency and can be run off of a battery power supply (read "quiet"). I have always been suspect of AC motors (read "noisy") or power supplies employing feedback for speed control (read "noisy"). I would like to design a Falhaber motor drive with a simple solid-state battery power supply. Speed control would be by a pot using the classic strobe disc on the turntable. Or by ear if you have = perfect pitch. You could set any speed you like. A facia under the pot knob could be marked for normal speed settings, which could be checked by the strobe disc periodically. The beauty of this is that any motor pully could be used - size would not be critical. A surplus motor for $10 to $20 and a few bucks for the power supply and you're there. If we do multiple tables it would be neat to burn pc boards for the power supply. http://www.micromo.com/ Cheers, Ken Ken Schei, P.E. Project Engineer Antarctic Support Associates Email address: scheike@asa.org Phone: 303-643-0163 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [miscellaneous snipped material from recent Joe List postings] Message from Robert Graetke has the incomplete web page he saved as file dc-motor.htm. The links are dead, but what the hey, it's only = 14K. From: analogtubeaudio@t-online.de [mailto:analogtubeaudio@t-online.de] Hi Joe=B4s, I=B4m looking for copy of artikel and schematic from the DC turntable motor kit published by Common Ground Magazine February 1999. Here is the link: http://www.originlive.com/dc-motor.htm Thanks in advance Robert Graetke =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D From: T. Loesch [mailto:ezee_e@hotmail.com] Hi there, I believe the complete article is here: http://www.restek.co.uk/restek6.htm The schematic is nothing I'm aware off. However seeing as you are in Germany, get the Motor Thomas Scheu sells. Feed it of a battery. = Cheaper and most defintly higher performance. Ciao Thorsten =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D From: Igor Kuznetsoff All, On the question of the DC side of this, of the 4 voltages (9, 12, 24, 42 V) I noted showing up in various parts of the thread, 12V battery power sure sounds like the most attractive.... -------------------------------- From: Schei, Kenneth I agree. ken =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Alex Mitaru [snip] Also, I bought from surplus a huge AC motor used to drive Ampex pro 1" tape machines, don't know if I could use it... thanks, cheers, alex =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D From: Steve Zettel Hi, all [ snip ] Please keep me on the list, and I will try to add some value as time and inspiration permit. I have some small expertise in electronic controllers and motor theory, and also in sound/vibration control from my professional career(s). Thanks for letting me participate, Steve Z =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D From: Steve Zettel Well, I will be happy to put my head together with Ken. I'll have to get up to speed (pun intended) with the project decisions, thus far =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D From: Mackris, Thom G. [ snip ] Motor: Ken, Chris & Igor voiced strong a preference for 12 v DC. I'm a rookie here, but in the past have found myself in agreement with them based on (a) general KISS principles, and (b) sonics. You'll find some brief comments about this from about 10 days ago on this subject in this growing = thread you have in your "Scheu" folder. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D ----- Original Message ----- From: Schei, Kenneth Sent: Friday, December 17, 1999 4:09 PM Subject: Scheu-Motor I received a price quote for a Faulhaber Micro-Motor Model 2842 (see attached URL) from the local sales rep. The motor would be ideal for our application. Note that the motor has Alnico magnets. Unfortunately, the price in quantities of 8 to 10 is $150 each. We need to scour the surplus sources to find something equivalent for a lot less, which should be doable. Ken Ken Schei, P.E. Project Engineer Antarctic Support Associates Email address: scheike@asa.org Phone: 303-643-0163 http://209.207.212.142/images/2842_7.PDF http://www.micromo.com/coreless.asp http://www.micromo.com/03application_notes/tutorial2.asp#sources ----- Original Message ----- From: Steve Zettel Sent: Wednesday, December 22, 1999 4:43 PM Subject: Re: Scheu-Motor I came across a *possible* candidate for our motor, but haven't been able to find the manufacturer's or a supplier's site for detailed spec sheets like Ken did with Falhauber. It's a Pabst #933-5310-013 2700 rpm, brushless 12VDC motor. The catalog entry reads: Non-reversible. 3500 rpm no-load speed. No-load current 0.6 amp DC. 2700 rpm @ 5 oz-in load @ 3 amps DC. Ball bearing. Dimensions: 4" dia x 1-3/4" long. Shaft: 0.275" dia. x 7/16" long. Four 1/8" holes on front flange for mounting. This motor is built inside out (their choice of words) the rotor is on the outside. This high-inertia rotor exhibits high strength gyro characteristics making it ideal for gyro demonstration purposes. It is listed in the paper catalog as: Stock #DCM9006 On the website it is listed as DCM9806 in the motors listing, and labelled 9006 at the picture. $9.95 from C and H Sales Company 1-800-325-9465 I called to check availability (they have more than 12 in stock ), but they didn't have any more information about them. I know Pabst makes some quality motors (my Oracle motor is a Pabst, similar in shape and size) and they made motors for the pro 1" Ampex tape machines, but it would be good to confirm this isn't one of the cheapies, if someone could find access to the specs. I'll keep trying, though I won't be back to work (and T1 access to the 'net) until Monday. Comments? Steve Z. ----- Original Message ----- From: Alex Mitaru Sent: Wednesday, December 22, 1999 4:52 PM Subject: Re: Scheu-Motor At 04:43 PM 12/22/99 -0700, Steve Zettel wrote: >It's a Pabst #933-5310-013 2700 rpm, brushless 12VDC motor. The = catalog >entry reads: > >Non-reversible. 3500 rpm no-load speed. Isn't this way too fast? To turn the platter at 33.333rpm we need a reduction of roughly 100; if the platter diameter is 12" the motor's shaft/pulley diameter should be 0.12"...Am I missing something here? cheers, alex ----- Original Message ----- From: Steve Zettel Sent: Wednesday, December 22, 1999 5:01 PM Subject: Re: Scheu-Motor Hi, Alex Well, several factors are at work here: 1. 3500 rpm is the no-load speed, 2700 rpm is the speed under a load of 5 ounce-inches at 12 VDC. 2. The speed is varied by varying the voltage applied to the motor. Steve ----- Original Message ----- From: ken schei Sent: Tuesday, December 28, 1999 12:09 PM Subject: Re: Scheu-Motor The no-load RPM is rated at full voltage and no load. The objective is to vary the voltage (and the pulley-platter ratio) to get the desired speed. At lower voltages and significant load the speed will be much less. 3500 RPM no-load speed is fairly low for a small DC motor. Ken ----- Original Message ----- From: Igor Kuznetsoff Sent: Wednesday, December 22, 1999 5:57 PM Subject: Re: Scheu-Motor Even if this was on the fast side, would that be a bad thing? Larger speed reduction would mean smoother running, and more torque. And the construction of this motor offers a nice flywheel effect, included. If we adopt the 2/3 point layout with the motor driving an idler, we would have 2 opportunities for speed reduction (2 pulley step-sizes), and running the motor at a higher speed may be desirable for improved speed stability, I would think. Do the motor experts concur ? Are there any drawbacks to doing that ? I know I don't care if it won't play backwards, not even to analyze old Beatles recordings. ----- Original Message ----- From: Thom Mackris / Joan Panzella Sent: Friday, December 24, 1999 12:02 AM Subject: Re: Scheu-Motor Ken, my dumpster diving idol has turned up some motors!! He called me this evening to tell me that our local Gateway electronics store has about a dozen Pittman 24V DC motors for less than $6.00 each! They have a 1984 date on them. He picked up one to play with today, = and on preliminary inspection, considers them to be a superior product ... *very* close in quality to his ($150.00) Faulhauber motor. [ ordering details snipped ] Cheers, Thom ----- Original Message ----- From: Steve Zettel Subject: Re: Scheu-Motor Great, Thom. I definitely want one! Now I can stop looking for the Pabst info (yippee!). Steve ----- Original Message ----- From: WilliamB Sent: Friday, December 24, 1999 8:44 AM Subject: Re: Scheu-Motor Hey Thom, Interest is hereby conveyed! whooo haaa! (translation: one please) BTW, when / if shipped then a copy of the table plans would be appreciated... let me know what my tab would be and I'll hustle a mo into her majesty's post office. best bill ----- Original Message ----- From: Chris Brady Sent: Friday, December 24, 1999 9:17 AM Subject: Re: Scheu-Motor Thom, Such a deal! If need be I can make a trip to Gateway on Monday. If not please get one for me and ryan. Chris ----- Original Message ----- From: Alex Mitaru Subject: Re: Scheu-Motor yes, yes, definitely, and don't even bother to ask me anymore, just go for it, I'm 100% into this...and even if you spend some money and it doesn't turn out that it is the right part, no big deal... alex ----- Original Message ----- From: Thom Mackris / Joan Panzella Sent: Friday, December 24, 1999 6:14 PM Subject: Re: Scheu-Motor Hurry shoppers, only 2 more shopping days until the day after Christmas!= So far, I have motors on order for the following folks. In the = interest of fairness (& potential motor availability) I'm listing folks in the = order of the timestamp of your replies, although I suspect that there will be enough for all respondents: Myself (1) Igor (1) Chris & Ryan Brady (2) Steve Zettel (1) Bill Mollard (1) Alex Mitaru (1) George Munger (1) (hasn't responded yet). Once I obtain the motors I'll update you. Merry Christmas all ... Thom ----- Original Message ----- From: Igor Kuznetsoff Sent: Monday, December 27, 1999 1:24 AM Subject: Re: Scheu Info I noticed mention, on one of the pages, of PLL (Phase Locked Loop) speed regulation of Scheu's 3-pole DC motor. Will this be possible with the motors we are considering ? I ----- Original Message ----- From: Jeremy Epstein Sent: Monday, December 27, 1999 6:57 AM Subject: Re: Scheu-Motor At these prices, I gotta be in. I will forfeit mine back to anyone actively building a turntable if it turns out I do not end up in that category. I assume this motor is in the desirable non-cogging category? -j ----- Original Message ----- From: George Munger To: Sent: Monday, December 27, 1999 11:19 AM Subject: Re: Scheu-Motor Thom, count me in. And thanks for all of your work on this project = (and for setting the 'rock solid' table-world straight on my recent promotion/demotion... easy come, easy go). I'm really busy with work related responsibilities, so thanks for allowing me some slack. I am learning so much from you and your guru friends! I hope to get back on-board (sorry) to the project's development as soon as I can have = time to have a life. With my sincere regards, George ----- Original Message ----- From: Thom Mackris / Joan Panzella Sent: Monday, December 27, 1999 11:15 PM Subject: Re: Scheu-Motor All, I picked up a dozen motors today ( I cleaned them out). I didn't have a chance to check them out thoroughly as I was with Joan and we were running a bit late. After getting home, and wiping them down (dust/light grime), I noticed a bit of lateral play (as opposed to the thrust direction which is parallel to the shaft) in a few of them . I'll pick out the best ten for us, prioritizing them subjectively in the order of your e-mail replies. All of the motors are very smooth - I'd bet there's no sonic difference between any of them. I'd group the motors into 3 categories: (1) little to no play - 6 of these (2) a barely perceptible bit of play - 3 of these (3) just a bit more play - 3 of these So ... based on the order of your e-mail replies, here's my attempt to be fair in distributing the motors: Myself Igor Chris Brady Ryan Brady Steve Zettel Bill Mollard *** neeed mailing address *** Alex Mitaru *** neeed mailing address *** George Munger Jeremy Epstein *** neeed mailing address *** Blair Hansen Ken was correct in that they are very smooth. As good as the best that money can buy? Beats me, but certainly they appear to be an excellent starting point, especially if we design our motor pods to accept different motors (requiring only a mounting plate change or a re-drilling). It will certainly allow us to have a baseline from which to operate ... perhaps comparing against one of the Pabsts or Faulhaubers. I'm running around a bit crazily at work right now, with final babysitting duties for our computer systems (partying at work on the 1st, and perhaps on the 31st too), and so I probably won't get around to packaging them up until next week. I only need three of your mailing addresses (Alex, I clumsily misplaced your mailing envelope ... sorry). Additionally, I'll enclose photocopies of the Scheu plans when I mail out the motors to you. Igor, I'm going to send you George Munger's motor, since when we get down to the nitty gritty, he'll probably be needing some of your shop skills to pull this project off (motor pod, whatever). This will give you the opportunity to have a pair of motors for your opposed motor experimentation. Cheers, Thom ----- Original Message ----- From: Steve Zettel Sent: Tuesday, December 28, 1999 12:21 PM Subject: Re: Scheu-Motor Great work, Thom! Thanks very much. Please let me know costs and where to send a check, and I'll get it in the mail. I know you are super busy at work right now. When things cool down, if you could send me whatever technical specs you have on the motors, I'd be interested to compare them to what I have on the Falhaubers and the Pabst I found. I may buy one of the Pabsts just to compare and play with, if = the two are similar enough to make comparisons meaningful. I'll report my findings to the group if there is any interest. To address Igor's question about PLL speed control -- certainly that is one of the schemes adaptable to our turntables. We can go as simple as battery power supply/rheostat (adjust frequently against room lighting "strobe" provided by the power co. -- usually with 0.1 Hz of 60) as Vb = decreases, through regulated battery or DC power supply and rheostat (adjust much less often), through PLL systems, to "PLC" (programmable linear control) systems providing high starting torque and/or a "record cleaning" mode, then dropping back to just enough voltage to run at 33.33 or 45. I guess we have to determine several things in a cost vs. simplicity vs. speed regulation vs. type of non-linearities introduced by the speed regulation and = error correction (rapid and high frequency vs. slow and low frequency, aka flutter and wow), etc. type of equation. The solutions may very well be different from individual to individual, depending on dollars, audibility of or tolerance for certain non-linearities, high-tech vs. low-tech vs. no-tech KISS . . . At least by using a DC motor we *theoretically* have a simpler set of solutions to speed control than most AC motors. Steve Z ----- Original Message ----- From: Igor Kuznetsoff To: Steve Zettel ; Thom Mackris / Joan Panzella ; Thomas Martin(w) Sent: Tuesday, December 28, 1999 3:51 PM Subject: Re: Scheu-Motor > To address Igor's question about PLL speed control > -- certainly that is one > of the schemes adaptable to our turntables. We can > go as simple as battery > power supply/rheostat (adjust frequently against > room lighting "strobe" > provided by the power co. -- usually with 0.1 Hz of > 60) as Vb decreases, > through regulated battery or DC power supply and > rheostat (adjust much less Regulation sounds like a good minimum requirement, I remember the the nerve-trying feeling of wondering from moment to moment how long the speed would stay "on", particularly while recording, from days best gone by. Frequent fiddling/checking of speed can become an obsessive nuisance, especially for those with good pitch sense. I *have* become a fan of the carefree freedom of PLL speed control such as I now enjoy in my current (belt driven) TT. > often), through PLL systems, to "PLC" (programmable > linear control) systems > providing high starting torque and/or a "record > cleaning" mode, then > dropping back to just enough voltage to run at 33.33 > or 45. I guess we have > to determine several things in a cost vs. simplicity > vs. speed regulation > vs. type of non-linearities introduced by the speed > regulation and error > correction (rapid and high frequency vs. slow and > low frequency, aka flutter > and wow), etc. type of equation. This sounds very attractive. Just how difficult/complicated/expensive is it ? (Only the last item really concerns me). I have read that slow, gentle speed regulation avoids wow & flutter caused by hunting & pecking for correct speed, giving the most solid pitch stability (which I am very sensitive to), and that makes a lot of sense. Igor ----- Original Message ----- From: Steve Zettel Sent: Wednesday, December 29, 1999 10:16 AM Subject: Re: Scheu-Motor Hi, all! [with respect to ordering Pabst motor to experiment with] OK, I will order one today. The Oracle's used a Pabst for awhile, and I believe I noted on Scheu's website reference to a Pabst, now no longer available to him. [with respect to Igor's advocacy of regulation being a minimum requirement as well as expressing a preference for PLL] This sounds like a good baseline starting point, that is, an adjustable regulated DC power supply (which could still be a deep-cycle battery = and regulator). I, too, don't want to be a slave to maintaining proper = speed control, and I have only so much tolerance for tweaking. [with respect to complexity and expense] Not very. The first steps will be to determine the load presented by = the platter/bearing and size a pulley to allow us a range of voltage = control for the motor. If we are lucky, we may be able to attain 33.33 and 45 rpm without pulley changes, simply by varying voltage. > I have read that slow, > gentle speed regulation avoids wow & flutter caused by > hunting & pecking for correct speed, giving the most > solid pitch stability (which I am very sensitive to), > and that makes a lot of sense. More than a few tt manufacterers subscribe to this view as well. The ideal is to have just enough torque to turn the platter and record with the stylus in the groove and no more. This is the rationale I infer from VPI's new SDS motor control/power supply -- higher voltage and torque for starting, dropping back to some minimum voltage when the platter is up to speed. We should be able to accomplish this at under a tenth of the SDS' $1000.00 price tag! Do we have an idea of the mass of the platter yet? I have read anywhere from 1" single thickness, 1 1/2" single thickness (pricy), 2" laminated. = Load will be the determining factor for much of the relationship between pulley size/motor voltage. Steve Z -----Original Message----- From: Steve Zettel [mailto:zettel@libby.org] Sent: Wednesday, December 29, 1999 10:16 AM More than a few tt manufacterers subscribe to this view as well. The ideal is to have just enough torque to turn the platter and record with the stylus in the groove and no more. This is the rationale I infer from VPI's new SDS motor control/power supply -- higher voltage and torque for starting, dropping back to some minimum voltage when the platter is up to speed. We should be able to accomplish this at under a tenth of the SDS' $1000.00 price tag! Do we have an idea of the mass of the platter yet? I have read anywhere from 1" single thickness, 1 1/2" single thickness (pricy), 2" laminated. = Load will be the determining factor for much of the relationship between pulley size/motor voltage. Steve Z ----- Original Message ----- From: Mackris, Thom G. Sent: Wednesday, December 29, 1999 10:20 AM Subject: RE: Scheu-Motor My guess about the platter mass is that we'll end up with 2-laminated = 1" pieces, yieldint the 2" (50mm) platter that Scheu ended up with. I may be wrong, but I think this will end up both (a) more cost effective than a 1.5" platter and (b) more massive. If I recall, Scheu specs out a 2" platter at 5 Kg (11 lbs). Thom ----- Original Message ----- From: Igor Kuznetsoff Sent: Wednesday, December 29, 1999 12:30 PM Subject: RE: Scheu Info [responding to comments about refrigertor motor noise and noise in general] I think you've just hit on an extra large "hot button" with that one, Steve ! Everybody must have run into *that* particular nuisance sometime ! I've been known to actually pull the plug on them more than once. In the last house I lived in, before the thing died altogether (and was replaced with a new, quiet, one), the fridge worked extra often (and ran up a bit of a bill due to extreme inefficiency), and, being old, really vibrated the floor. Despite being on the other side of the house, it resonated the entire floor structure due to an unfortunate turn of acoustic negative serendipity (negadippity ?). I ended up putting the thing on fairly stiff 1/2" thick rubber pads to detune that resonance, which helped quite a bit. Unfortunately, I then discovered that it was also putting an amazing amount of *electrical noise* *into* the circuit it was on, and, from there, was using the house wiring to broadcast that noise *all over the house!* When it's (old) motor started up, I could hear it run on either of my (main) systems. Even after putting *everything* behind power filtering (I design filtering into pretty much all my PS's nowadays), I could still hear the startup, which meant that even if it was not as audible afterwards, it still had to be affecting my noise floor. WAR !! I decided that my house power grid was just too much of an antenna to overcome by local filtration, so I decided to cut off the noise at its source. I ran the fridge through an inexpensive Corcom-style surplus power filter with the largest rating I could find, cheap. This worked! This is something to keep in mind anywhere automatically running largish electrical motors are plugged in, which might run when you do your critical listening. Motors are capable of putting a lot of noise into your *entire house*. Surplus outfits like MECI sell filters with capabilities often running up to as much as 40 amps for next to nothing ($3-10 typically). ----- Original Message ----- From: Steve Zettel Sent: Wednesday, December 29, 1999 4:27 PM Subject: Re: Scheu Info on 12/29/99 12:30 PM, Igor Kuznetsoff at gorkuz@yahoo.com wrote: I agree that noise filtering is a must for power supplies, especially when dealing with minute phono cartridge signals, or high-gain phono = preamps. Filtering at the source is always prefered if possible, like your refrigerator. In one of my other hobbies, amateur radio, I enjoy DXing on the HF = bands (chasing weak-signal, far-away contacts with other operators). I am = very fortunate to live in a very electrically quiet home, in a quiet rural area (trains excepted). Even though we have above ground wiring, and I have = a "pole pig" right outside my listening room window, we have only been plagued by electrical noise once. Some neighbors had a fence charge that was arcing inside the control box, and radiated a tick - tick - tick - tick throughout the lower HF spectrum. Being familiar with fence chargers from my days on the family farm, it was pretty easy to track down, and the neighbors were amenable to a quick fix. The new neighbors are not so friendly, but don't use the charger, either. They appear somewhat intimidated by the two towers I have on the back of my property (100' and 120'). At times they have made remarks about "CB interference", but since I invited them over to use the phone, and watch the TV or listen to music while I operated full-power on the radio, with NO interference to my own household equipment, they = have quieted down. Motors can be some of the worst offenders, and often emit a broadband hash that is very hard to clean up. Steve ----- Original Message ----- From: Thom Mackris / Joan Panzella Sent: Thursday, December 30, 1999 11:18 PM Subject: Re: Scheu-Motor I just got back from Ken where we checked out the Pittman motors on a = DC power supply he has from his model railroad days. The supply has a scale on it not related to any particular voltage. All of the motors started up at the same point on the dial (25 on a scale of 1 to 90). They're not as smooth as his Faulhauber & it will be interesting to see if this has = any effect on the 'tables' sound. As I mentioned before, at $4.95 plus = tax, they're an excellent starting point. From Ken's experience with = motors, he estimates that in today's dollars they're $100.00 motors and very nice. At the same time, he's going to use the Faulhauber in his project. A note about the bearing play. Even the most "sloppy" of the 12 = Pittman motors had about the same play as Ken's ultra smooth Faulhauber, so I guess I was being overly critical in my comments in this area. I'll ship them sometime next week, along with copies of the engineering drawings & plans. Bill, I found your address in a Word document, apparently from when I sent you a copy of the Medallion II cabinet plans last = year. If your address hasn't changed, then I have it. I'm only (foolishly) missing Alex's address. I got the opportunity to hear Ken's new Grado Platinum Reference cartridge that Santa brought him. Very nice. Only about 15 hours on it so far & he hasn't dialed it in completely. It's actually a very rough install at this point due to Christmas company and the strange headshell on his Thorens tonearm. The Thorens has some sort of threaded, sliding plate that = sits in rails in the headshell and is designed to have the screws inserted from the bottom of the cartridge and into the plate. The Grado has tapped threads with the screws entering from the top. Ken managed a temporary = friction fit as he ponders how he'll get screw clearance while at the same time keeping the arm stock, for possible resale. For all of these reasons, the = setup is less than optimal at this point. I would say that Steve's appraisal of the cartridge (from his = experience of a friend's) is in line with what I heard & what's been written about = it; this being in a non-optimized setup with an unbroken in cartridge. Perhaps the slightest woolieness in the bass, but I can see the cartridge speeding up as it breaks in. My guess about this bass thing is that its as much a cartridge/arm interaction as anything else ... some arms (different effective masses) will exacerbate characteristics more than others. = The Thorens arm appears to be a very nice match for this cartridge. What astonished me about the cartridge is how *well* it does the space = thing. I didn't expect this from what I've read, and again, I'm betting that = this is a tonearm compatibility thing. All in all, I could easily live with this cartridge and never look back. It makes me not want to hear Steve's Clearaudio ... especially at the price :-(( It would be scary to hear = a cartridge that pays more homage to the music than this Grado does. I think I could easily live flaws that might become noticible over long term listening, for the things that it does right ... violins, voice, woodwinds (ah ... the woodwinds are heavenly and yet earthy at the same time). It's gettin late, and I'm pooped ... Cheers, Thom ----- Original Message ----- From: Steve Zettel Sent: Friday, December 31, 1999 8:06 AM Subject: Re: Scheu-Motor on 12/30/99 11:18 PM, Thom Mackris / Joan Panzella at tmackris@earthlink.net wrote: > I just got back from Ken where we checked out the Pittman motors on a DC > power supply he has from his model railroad days. Can you or Ken give us a rough idea of what the start up voltage is (I am assuming this is without load)? Maybe just stick a voltmeter across the RR power supply. > A note about the bearing play. Even the most "sloppy" of the 12 Pittman > motors had about the same play as Ken's ultra smooth Faulhauber, so I guess > I was being overly critical in my comments in this area. Good news there. When you say "not as smooth" as the Falhauber, do you mean in the "spin the motor by hand" test, or in a vibration sense when compared with a running Falhauber? Thanks, Thom. Happy New Year (I'm at work this morning, and will be until 0400 tomorrow. What Fun!) Steve ----- Original Message ----- From: Thom Mackris / Joan Panzella Sent: Friday, December 31, 1999 8:55 AM Subject: Re: Scheu-Motor Steve, When we put Ken's Faulhauber on the power supply, it started moving = when the dial got to '15'. The Pittmans started moving when the dial reached '25'. >From this, I'm guessing that the Pittmans need 3 volts or less to start up (see below). Note that that Ken's Faulhauber can start up with a single 1.5 V AA battery. The 24 v Pittmans would *not* start, with 4 AA's in parallel (measured = ~ 5.6 volts) ... not enough currrent from the batteries, I suppose. When running (with current through them), the Faulhauber had a barely tactile vibration, whereas the Pittmans did have a distinct vibration = in comparison. Ken has played with AC motors and says that the Pittmans are much smoother than them ... just not in the same league as his Faulhauber. I have to run, more to follow this afternoon. Cheers, Thom ----- Original Message ----- From: Schei, Kenneth Sent: Monday, January 03, 2000 9:37 AM Subject: RE: Scheu-Motor The specific gravity of acrylic sheet is 1.2, or 74 pcf. That may vary a little according to brand or grade. By my calculations, a 12" diameter by 2" thick platter would weigh 9.7 pounds. Allowing some additional weight for the spindle/bearing shaft, Scheu's weight of 5 Kg is reasonable. Ken Ken Schei, P.E. Project Engineer Antarctic Support Associates Email address: scheike@asa.org Phone: 303-643-0163 ----- Original Message ----- From: Igor Kuznetsoff Sent: Sunday, January 09, 2000 1:49 AM Subject: Sandbox (& motor) Thom, Got the motors, looked at them, spun them , wobbled the shafts, etc. Noticed that they are nice, solid feeling units, but that the casings *ring*. This probably means nothing, shouldn't transfer any noise through the belt, but my automatic "old hand" response thought is *no ringing anywhere in *my* equipment!*. Don't know if the motor makes any noise at all yet (such as whining), but my immediate thought is to stick a bit of black goo (or maybe some "moosgummi" in the housing as in the Scheu) on the casing, just in case, doesn't cost anything, just to be sure. Interesting review on the Nottingham Analogue Hyper Spacedeck (clever name) that you included, by Art Dudley, tx. I notice the heavy rubber (?) rings (2) around the platter for damping (damn-ping/ping-damning ?). Also the mention of flywheeling the pulley. I thought it amusing that the writer also thought about running it backwards to listen to the Beatles Igor ----- Original Message ----- From: Igor Kuznetsoff Sent: Monday, January 17, 2000 4:10 PM Subject: RE: Scheu Motor Supply >I will probably run the motor off of battery power >with a little battery bracket hidden in the >subchassis. > * No power cord!* >Ken I like that idea. A power cord bridges the isolation of the air suspension. The battery could also be put in a case with a nice looking top, and mostly buried in the sand. I ----- Original Message ----- From: Schei, Kenneth Sent: Thursday, January 20, 2000 8:17 AM Subject: RE: Scheu-Bearing & Platter It would certainly be feasible to use a train power supply to power the motor. They come in all price ranges, starting quite cheap. That's what Thom and I used to test the Pittmans. A simple improvement would be to wire a capacitor across the output for additional smoothing. Your technique of using variable DC and a strobe disk is what I intend to do. An effective DC speed control also can be made using an adjustable 3-pin voltage regulator (LM317) with the output adjusted by a pot wired into the regulator circuit. I built one of those for model railroading and I'm going to dig it up and start experimenting with my drive system. But the system I may end up with is a battery source of the appropriate voltage with a pot to adjust the speed. Attached is a strobe disk design that anyone is welcome to use. Ken ----- Original Message ----- From: Steve Zettel Sent: Friday, January 21, 2000 12:50 PM Subject: Re: Scheu-Bearing & Platter Thanks, Ken, for both the strobe disc and the discussion. I would like to solicit input from the members about what kind of power supply they would like to have, or perhaps more to the point, what they are willing to live with, realizing that as complexity rises, so does cost. (Funny thing about that). Possible canidates for considerations as power supplies are: 1. Battery and rheostat -- simple, low cost, eliminates all problems with rectifying AC to DC (residual ripple, etc). Might be considered a "purist" solution, elegant in its simplicity. Would require some operator intervention during start-up (get platter rolling, adjust speed with strobe disc, periodically adjust rheostat back to 33.3 rpm as battery voltage falls off. Other issues: current requirements of = Pittman/Faulhaber/Pabst/other motors may make large capacity rechargable gel cell or lead-acid car/motorcyle/golf cart battery necessary (this could be a plus adding mass to the TT stand!); depending on motor characteristics and pulley = sizing, 45rpm operation may not be feasible without a pully change, or dual pulleys. Rheostat may have to be quite large to handle heat dissipation, depending on voltage dropped and current levels. (The Faulhaber must be quite efficient, Ken, for you to consider having the battery and controls in your subchassis! Please tell me more.) 2. Variable DC power supply -- this could be as simple as a commercially available model train power supply, a surplus lab-grade variable DC power supply, or an owner-built DC supply consisting of the appropriate transformer, rectifier, capacitance and rheostat. As Ken points out, a three terminal voltage regulator IC (with proper heat-sinking) and rheostat would give us a regulated variable DC supply. I consider all three approaches to be essentially similar electronically, so the key issues would probably be cost, and voltage ranges required. Which again depends on motor and pulley considerations. I need to do some pricing of train power supplies and variable DC power supplies -- it may be most cost-effective to go with = a commercial solution that we may be able to get a good price on (like motors), rather than trying to build our own. This last would be a = bonus for those group members who do not feel comfortable rolling their own. 3. Sophisticated supplies -- similar in concept to the VPS SDS or Wilson supplies/controllers, could be designed to give a higher start-up voltage and torque, push button speed control, multiple speeds, etc. This could get somewhat pricy and take awhile to design, especially if we incorporate feedback from the platter for speed control (which also adds it's own concerns about speed accuracy, and more importantly, speed stability [dead bands, correction frequencies, etc]. Optical coupling would seem the only way to go for feedback. Ultimately, the same basic determinations are a necessary first step -- pulley diameter and motor characteristics. Personally, I am leaning toward solution 1. or 2. on the KISS/Cost principles. Also, the battery power supply may prove to be the ultimate purist supply due to absolute freedom from power supply ripple. An additional reason is that I am not sure when I would get the design = done for 3. (I know I was the one who brought it up). I am so fired up to get this puppy in operation, that if it were up to me alone, I would probably consign 3. to "tweeks and embellishments to be tried later", like next winter. Here is what I propose to do: Weight the platter of my Oracle to simulate the 3" thick acrylic = platter of our TT. Find some likely pulley diameters (probably just use my hole saws and cut some discs out of hardwood for now). Make a test fixture out of a hunk of Schedule 80 PVC with a hunk of = lead in the bottom and a cover plate to mount motors to. Make some belts, probably out of string, or maybe slicing up some inner tube I have laying around. Use a nominal 13.8 VDC regulated DC power supply I have on hand for my amateur radio equipment and an external dropping rheostat and make some voltage vs. pulley vs. speed readings. Hopefully, NOT let the "smoke" out of anything in the process. I will see how much I can get done before I leave on active duty 30 = Jan. Otherwise, I'll jump back into it when I get back. Meanwhile, if everyone is not too burnt out, or licking their wounds over the platter/bearing design, I welcome your discussion about what everyone is looking for in a power supply. Ken, could you please re-send me the URL or other contact information for the model train supplier you mentioned previously? I can't seem to find it in the bazillion turntable e-mails I have been saving! Thanks. Steve Z ----- Original Message ----- From: Mackris, Thom G. Sent: Friday, January 21, 2000 2:10 PM Subject: RE: Scheu-Bearing & Platter Steve, My gut tells me Option #2 is the one which will fly (either store bought, or designed). Here's my thinking: Option #1: I know that Joan would not let a lead-acid battery in the house. I'll bet there are other wives who will also exercise veto power in this area. Joan is great as far as accepting what most wives would immediately nix on cosmetic principles (as long as she likes the sound), but things like fiberglass and lead-acid turn on her switches. Option #3: Complex and ambitious (expensive too?) - a "maybe" project for next Winter (or beyond). Option #2 (Thom's default winner): With respect to store bought supplies, I'll drop by Gateway Electronics in the next couple of days (after talking with Ken about requirements) and see what kind of stuff they carry. This might be an option that some folks would want to avail themselves of. An obvious consideration which will involve both you and Ken is the possibility (probability?) that the Pittmans will be a short term solution. They certainly have a higher start-up requirement than Ken's = Faulhauber, and I suspect than your Pabst too. A flexible design would seem to be necessary in order to facilitate a future motor upgrade from the Pittmans. A thought for you and Ken. Surely a DC supply must have been covered = in either Analog Addicts or the Phonogram List. I'll search through the = AA archives tonight or tomorrow. There seems to be some convergence in this area (LM317 regs. for example) and we might be able to stand on the shoulders of our predecessors. Thanks for the input. Thom ----- Original Message ----- From: Steve Zettel Sent: Friday, January 21, 2000 7:17 PM Subject: Re: Scheu-Bearing & Platter Brief comments appended below: The SAF (Spousal Acceptance Factor) is always of paramount importance. = A full size lead-acid battery is probably overkill (but are we not *audiophiles*?), but a smaller, sealed gel-cell in a nice wooden box would be more unobtrusive. . . > > Option #3: > > Complex and ambitious (expensive too?) - a "maybe" project for next Winter > (or beyond). Well, I know myself too well, and if I don't get most of this project done this winter/early spring, when the weather starts getting nice around here I spend less and less time indoors. And also, "she who must be obeyed" to-do list kicks into full force with the spring weather -- the garden, the painting, repairing snow damage and picking up deadfalls and branches, etc etc etc. > > > Option #2 (Thom's default winner): > > With respect to store bought supplies, I'll drop by Gateway Electronics in > the next couple of days (after talking with Ken about requirements) and see > what kind of stuff they carry. This might be an option that some folks > would want to avail themselves of. There are still lots of tweeks we can apply to store-bought supplies 8^) > > An obvious consideration which will involve both you and Ken is the > possibility (probability?) that the Pittmans will be a short term solution. > They certainly have a higher start-up requirement than Ken's Faulhauber, and > I suspect than your Pabst too. A flexible design would seem to be necessary > in order to facilitate a future motor upgrade from the Pittmans. As long as we buy or build a variable DC power supply with a wide = enough range of output voltage, we will have covered the biggest consideration for the supply, other than regulation. The pulley diameter is a motor = issue. I have to admit, I am intrigued by Ken's Faulhauber motor too. It will be difficult to specify a "mass buy" of motor pulleys if we all use different motors, but we can at least find out a small range of acceptable = pulleys for each motor. I am sure ready made pulleys of brass, if not acrylic, are readily available at nominal cost for the hobbyist market. > > A thought for you and Ken. Surely a DC supply must have been covered in > either Analog Addicts or the Phonogram List. I'll search through the AA > archives tonight or tomorrow. There seems to be some convergence in this > area (LM317 regs. for example) and we might be able to stand on the > shoulders of our predecessors. > > Thanks for the input. > Thom You are welcome. Steve Z ----- Original Message ----- From: Chris Brady Sent: Saturday, January 22, 2000 12:02 AM Subject: Teres-Motor&Supply I am leaning towards #2. It seems that what we need is: 1) Constant voltage. No thermal drift or change over time. I would like to be able to calibrate the speed and then forget it. Maybe re-check every 6 months. 2) Very good regulation. I suspect that this is the crucial part of the design for good sonics. A battery alone would be fair for reguation, but probably not so good for constant voltage. Fortunately, there are a number of superb reguator designs available that we could adapt for the motor control. I have several Audio Amateur articles that about regulator design that I need to dig out and re-read. If anyone is interested I can scan in the articles and send them to you. As Ken mentioned a simple LM317 adjustable regulator circuit would offer reasonable performance and it would be easy and cheap. It would be a good starting point. In the longer term it seems that we would want something with higher performance. Using a precision voltage reference would offer superb long term stability. To get rock solid regulation we could build the regulator around a high speed op-amp and also pre-regulate the incoming DC with an inexpensive 3 terminal regulator. If we really want to go nuts we could also do remote sensing. This is when the regulator senses the output voltage at the motor terminals so that the small drop in voltage from the motor lead wires is compensated for. I have built similar regulators in the past and they are neither difficult or expensive. I think that the bulk of the cost for the power supply will be the case, controls and power source (battery or AC transformer, rectifiers and such). Shooting from the hip I would estimate that the cost difference between a simple LM317 regulator and an exotic high performance regultator would only be about $15. I have a high quailty regulated DC supply (3-25v) that we could use for testing. Once we figure out the voltage we need it would be a simple matter of just adjusting a few resistors in the regulator to change the output voltage. Chris ----- Original Message ----- From: Schei, Kenneth Sent: Monday, January 24, 2000 10:00 AM Subject: RE: Teres-Motor&Supply Good points, Chris. A regulator such as a 317-based one will provide a more constant voltage than a battery which varies with age, and thus would need frequent re-calibration. Thus a regulator seems the way to go. Of course, there's no reason why the regulator can't be powered by a battery. I also agree that we should start with a simple regulated supply and then = judge by listening to see if we need more. Ken Ken Schei, P.E. Project Engineer Antarctic Support Associates Email address: scheike@asa.org Phone: 303-643-0163 ----- Original Message ----- From: Thom Mackris / Joan Panzella Sent: Sunday, January 23, 2000 10:25 AM Subject: Scheu/Teres - Motor & Power Supply Chris, Ken, Steve - A few comments from Igor. His online online time has shrunk at the moment, and so I compiled his quick comments into one e-mail. Cheers, Thom ---------- Regarding batteries & choice: A gel cell is what you want. Smaller, sealed, safe, and, most important, ok with a deep discharge, which common lead-acid cells cannot tolerate on a repeated basis. Only the exotic new "spiral cell" deep-discharge lead acid auto stereo batteries will stand up to that, and they are exorbitantly expensive. Also, most gel cells can be laid on their sides in use (check model before using), so they can be buried in the sand as they are only about 2" thick, and heavy. In addition, these are what power emergency lighting, so there are plenty of automatic charge maintenance circuit boards around, and you should be able to pick up something surplus. The most common are 6V, but 12V are around also. ---------- Regarding more sophisticated power supplies: The best of them is the regulator in the KG-5 P.S. I use. It is in the Audio Amateur. The KG-5 itself is not needed, and no longer available, anyway, but, last I looked, this summer, the PCB's for it were still available cheaply. Whether or not the stuffings are available in toto or not I don't remember, but the Linear Technology regulators are, and that's all that is hard to get, in *one* of the polarities (it takes a pair + = & - for a *bi*-polar supply). Only *one* is needed for this, and it doesn't matter which, so it may = as well be the cheaper, easily available one ( might have been the +, not sure). The rest of the circuit should be easily adaptable, so long as the voltage range needed is within the regulator's capability, which it probably is, though I would have to find the spec sheet which is buried somewhere. Perhaps LT has a website that that could be pulled up from, many manufacturers do. The other, I don't remember offhand which, is available from either Digi-key or Mouser for half the Old Colony price. ---------- Regarding choice of regulator chips: > >As Ken mentioned a simple LM317 adjustable > regulator > >circuit would offer reasonable performance and it > >would be easy and cheap. It would be a good > starting > >point. > It *may* be good enough, and certainly cheaper, though the differences are rather small on a one-off basis. The Linear Technologie chips the LT units are-the best, and adjustable, usually via a fixed resistor, but that could be substituted by a potentiometer plus a fixed limiting resistor, so that the setting resistance could not go to zero by accident. -------------- ----- Original Message ----- From: Steve Zettel Sent: Monday, January 24, 2000 1:06 AM Subject: Re: Scheu/Teres - Motor & Power Supply Excellent discussion. Looking at the fact sheets Chris sent me re the Pittmans, I don't think we'll have any problem with finding a good solution for pulley size and operating range. Ditto 33 and 45 rpm with the same pulley. Given the Pittman as a "generic" motor, we should be able to get just = as sophisticated and pricy with any other motors that fall in the same general specs for voltage and torque as we want, should the Pittmans prove to = be too noisy or vibrate, etc. more than anyone wants in a world-class TT. Thom's description of the smoothness of the Faulhauber has me = intrigued. Steve ----- Original Message ----- From: Steve Zettel Sent: Monday, January 24, 2000 2:47 PM Subject: Re: Teres-Motor&Supply on 1/24/00 09:53, Mackris, Thom G. at tgmackris@vicorpinc.com wrote: Keep those ideas coming. Ken, Chris, Igor and Thom all make good = points. One point we may want to consider is the voltage range of our variable, regulated power supply. Although this is linked to motor selection, having a wide range of power supply voltages, within the motor's capability curves, makes pulley selection less critical, and enables 33/45rpm operation without pulley changes. For anyone who hasn't seen the .pdf file of Pittman motor data, I find the information to be very helpful, particularly the graph for the 8512 load/speed/torque curves. Steve ----- Original Message ----- From: Schei, Kenneth Sent: Monday, January 24, 2000 3:36 PM Subject: RE: Teres-Motor&Supply The following are some parameters for the Pittman and Falhauber motors: TURNTABLE MOTORS 12 VDC Parameter Units Pittman 8512 Falhauber 2842 I no-load* Amps 0.22 0.05 I stall* Amps 2.74 - Torque Oz-in 5.1 6.88 Velocity constant RPM/V (~640) 435 Roter Inertia Oz-in-sec^2 1.3x10^ -4 1.8x10^ -4 No-load speed RPM 7729 5100 * At full speed. I is proportional to rpm, as is V. The actual I = will obviously be somewhere between no-load and stall. If we have a 12" diameter platter and a 1/2" diameter motor pulley, at 33.33 rpm platter speed the pulley will rotate at 33.33x12/.5 =3D 800 rpm. The following = voltages are derived: Pittman: 800 rpm / 640 rpm/V =3D 1.25 V No-load I: 0.22x1.25/12 =3D = 0.023 A Stall I: 2.74x1.25/12 =3D 0.28 A Falhauber: 800 rpm / 435 rpm/V =3D 1.84 V No-load I: 0.05x1.84/12 =3D 0.0077 A It appears that Pittman's load charts are based on about 1/2 of the stall currents. I couldn't find stall currents for the Falhauber. We need = to verify that the motors will run reliabily at the low voltages required, with the platter load on them. I don't think our motor pulley can be much smaller than 1/2" diameter, or we may experience belt slipping. An option to raise motor rpm would be to have a double reduction with an idler pulley, which would be an added complication but may also yield better motor isolation. The Falhauber runs at much lower current than does the Pittman, which makes it a better candidate for battery power. There is research and experimentation yet to be done. Ken Ken Schei, P.E. Project Engineer Antarctic Support Associates Email address: scheike@asa.org Phone: 303-643-0163 ----- Original Message ----- From: Steve Zettel Sent: Monday, January 24, 2000 10:51 PM Subject: Re: Teres-Motor&Supply Nice analysis, Ken. I am particularly impressed by the Faulhauber's efficiency. A couple of points: The Pittman 8512 motor I have is marked on the label "24 volts". I have been using the Pittman data sheet for 24VDC operation in my rough calc's; I didn't see a 12VDC graph in the .pdf file I had considered a 0.25 diameter pulley to allow operation of the Pittman at higher voltage and rpm, seeking to get motor rpm above 1000 rpm if possible. To compensate for the smaller diameter drive pulley, I plan to experiment with both recording tape (as Dr. Wilimzig) and wide rubber belts, = either cut from innertubes and/or available out of the industrial catalogs. Vacuum cleaner belts are another possibility, as is almost any belt-driven appliance. (I have found that for just about any item like this, there are several suppliers with catalogs that make them, it just takes some looking.) FWIW, the drive belt on my Oracle is about 1/16" wide rubber and the drive pulley has about an effective diameter between 1/4 and 1/2 inch. It operates without slipping under normal and light cleaning loads at both 33 and = 45 rpm without slipping. Drive pulley material is brass, platter driven = surface is polished aluminum alloy. Steve Z ----- Original Message ----- From: Igor Kuznetsoff Sent: Monday, January 24, 2000 11:35 PM Subject: Re: Teres-Motor&Supply Using an idler pulley as a step-up would allow a wide ratio of RPM changes, as well as improving motor isolation, and allowing upgrading to a balanced drive system at the platter (with a second idler). Parts Express has a fairly wide range of flat belt sizes, cheap. I ----- Original Message ----- From: Igor Kuznetsoff Sent: Monday, January 24, 2000 5:26 PM Subject: RE: Motor& Supply Ken, What are the .05 &6.88 figures in the "I-no load" line? Is that the Falhauber spec with a loss of formatting? Also, the 640 RPM & 435 RPM for Pittman & Falhauber, are those the stall speeds ? I am trying to puzzle out what 800/640 & 800/435 is supposed to represent in electric motor terminology. The voltages involved are surprisingly low, and suggest that use of a common 6V gel cell and charge maintainer board such as are common in emergency lighting (and surplus available). This would be good news as such a system would be fairly economical to procure. To the point of cannibalizing / adapting a cheap emergency light out of any discount supply, maybe even Home Depot, possibly. I > >Fortunately, there are a number of superb reguator > >designs available that we could adapt for the motor > >control. I have several Audio Amateur articles > that about regulator design that I need to dig out > >and re-read. If anyone is interested I can scan in > >the articles and send them to you. The best of them is the regulator in the KG-5 P.S. I've used. It is in the Audio Amateur. The KG-5 itself is not needed, and no longer available, anyway, but, last I looked, this summer, the PCB's for it were still available cheaply. Whether or not the stuffings are available in toto or not I don't remember, but the Linear Technology regulators are, and that's all that is hard to get, in *one* of the polarities (it takes a pair + & -). The other, I don't remember offhand which, is available from either Digi-key or Mouser for half the Old Colony price. That's for a *bi*-polar supply. Only *one* is needed for this, and it doesn't matter which, so it may as well be the cheaper, easily available one ( might have been the +, not sure). The rest of the circuit should be easily adaptable, so long as the voltage range needed is within the regulator's capability, which it probably is, though I would have to find the spec sheet which is buried somewhere. Perhaps LT has a website that that could be pulled up from, many manufacturers do. > >As Ken mentioned a simple LM317 adjustable > regulator > >circuit would offer reasonable performance and it > >would be easy and cheap. It would be a good > starting > >point. > It may be good enough, and a bit cheaper, though the differences in total cost are rather small on a one-off basis. > > > >In the longer term it seems that we would want > >something with higher performance. Using a > >precision voltage reference would offer superb long > >term stability. And that's exactly what the LT units are-the best, and adjustable, usually via a fixed resistor, but that could be substituted with a potentiometer plus a fixed limiting resistor, so that the setting resistance could not go to zero by accident. I ----- Original Message ----- From: Schei, Kenneth Sent: Tuesday, January 25, 2000 7:29 AM Subject: RE: Teres-Motor&Supply I apologize for the loss of format in my motor comparison matrix. I = was going to attach it to the email as an Excel file, but I didn't for simplicity. As Einstein said, "Make it as simple as possible, but no simpler." I didn't have the Pittman motor in front of me and guessed that it was 12 V. 24V is better, because the operating voltage will be proportionatly higher. I'm liking the idea of an idler pulley more as = I think about it. As Steve points out, it also increases the torque, = just as shifting to a lower gear in you auto does. More torque equals better platter control. 0.05 is the I no-load of the Falhauber, and 6.88 is the torque of the Falhauber. 640 and 435 are = the respective RPM/Volt for the Pittman and Falhauber. 800/640 is thus the voltage required to run the Pittman at 800 RPM. Ken Ken Ken Schei, P.E. Project Engineer Antarctic Support Associates Email address: scheike@asa.org Phone: 303-643-0163 ----- Original Message ----- From: Mackris, Thom G. Sent: Monday, January 24, 2000 5:36 PM Subject: RE: Motor& Supply The Pittman PDF file somewhat large ~ 350K and Chris only forwarded it to the "motor" folks who had corporate serves that would tolerate largish files (my home ISP - Earthlink gripes when it gets over 1 meg, but I believe Yahoo is smaller ??). I found the website that Chris pulled it off: http://www.pittmannet.com/quick_index.html My PDF file says: Bulletin LCM - Lo Cog DC Servo Motors, Series 8000, 9000, 14000. This is the first link on that page. Cheers, Thom ----- Original Message ----- From: Steve Zettel Sent: Tuesday, January 25, 2000 12:32 AM Subject: Re: Teres-Motor&Supply >>> > Using an idler pulley as a step-up would allow a > wide ratio of RPM changes, as well as improving motor > isolation, and allowing upgrading to a balanced drive > system at the platter (with a second idler). > Parts Express has a fairly wide range of flat belt > sizes, cheap. > I > No argument there. I have a copy of Parts Express at home that I will look at after work in the morning. An idler pulley may indeed be the only way of achieving the platter speeds required with high enough torque and without belt slippage. An idler may be a source of motor isolation, but might also be a source of additional noise/vibration on it's own, too. Certainly, it increases = the complexity of the drive train. Likewise a "balanced drive system" at the platter might be an upgrade, or again, a source of vibrations depending on the precision of bearings = and alignment. Not meaning to be argumentative -- just playing devil's advocate. As I mentioned before, VPI's latest official upgrades to their top-line turntable included all of the following: Adding the "SDS" motor control/power supply Upgrading platter Upgrading main bearing Removing flywheels and idlers Not saying theirs is the "right" way or only way to do turntables (though it appears they are copying us), just that VPI doesn't seem to be shy = about upgrades (and prices) if something makes an audible improvement. But then, their idler system might not have been near as good as ours = is going to be! 8^) Steve ------_=_NextPart_000_01BF70F1.FD585B9E Content-Type: text/html; name="dc-motor.htm" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="dc-motor.htm" turntable motor UPGRADE for all turntables

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We supply a DC motor kit that is easy to fit to almost every deck = ever produced.  This is simply one of  the most cost effective and massive = upgrades that you can make to your system (see attached review). Decks benefiting from this upgrade include = Linn  Roksan  Pink triangle  Rega   Thorens  VPI   Michell  Project =    Garrard and Sysemdek to name but a few
    The kit  represents close to the ultimate in = motor and power supply quality along with 33rpm & 45rpm speed selection.  It comprises a = highly advanced non-cogging DC motor, an extremely accurate polished pulley, motor attachment plate, = specially designed 2 speed voltage regulation circuit and fully built power supply  along = with switch and wiring.  We can provide power supplies for either 240 / 230V, 50 Hz or 110V, 60 Hz mains supplies.
    The kit is easy to build from the schematic diagram = supplied and is well within the scope of anyone who can solder (no electronics = "know how" is required). All this comes for =A3250 (add =A325 for fully soldered and = tested voltage regulation board).  Note:   This combination is far superior in performance to any = electronic power supplies (usually costing between =A3600 and =A3900). The kit can be = installed inside your plinth if it has room or in an external box. No safety risk exists due = to the low 6V output from the fully built power supply (only the = regulator circuit needs to be built).
    Will the kit fit your deck? If you have doubts, it = may help to know that we provide a 1 month money back guarantee.  If you cannot fit the = kit then we will give you a full refund.  Motor body is 42mm long and 29mm = diameter. The pulley is 11mm on top of this and 10.5mm in diameter. Speed is infinitely = variable via a dial resistance.

3D"dcKit features:

The high grade DC motor is a radical new breakthrough design (1997) = with absolutely no cogging effect due to it's ironless core. The cogging effect is the = downfall of  a/c synchronous motors and most DC motors. The motor is also fitted with = precious metal brushes and is highly reliable.

>    The power supply is so well regulated = that it supercedes even lead acid batteries (as used by many high end = pre-amps). This feature has been fully exploited by the highly = developed but simple circuitry, specifically designed for the kit = motor.
>     The motor plate enables easy = fitting to most decks and also enables belt tension to be adjusted (critical to optimising = performance).  Due to the vibrationless nature of the motor, it does not need rubber band = decoupling and other methods employed on some decks to isolate their existing = motors.  In fact this motor can be attached on the platter sub-chassis with no noise = breakthrough = whatsoever!
>    You can set the variable speed setting = for your particular deck no matter what size your platter or = sub-platter.

3D"turntableThe kit is = applicable to linn  roksan   pink triangle  rega  thorens  vpi  michell  project garrard  = systemdeck

 

 

  =20

3D"Home" = 3D"Up" 3D"Kit 3D"more 3D"dc 3D"dc 3D"dc

------_=_NextPart_000_01BF70F1.FD585B9E-- [Editor's note: This second digest on the Motor & Controller design begins with a forwarded e-mail from Manfred Huber. The real information about the design begins here. Note that Manfred maintains his own web site and that the zip file is not included here. He is in the process of documenting his work and due to the pride he takes in his work, he does not wish an incomplete product to be displayed. We are most grateful for Manfred's volunteering to help us in this area of the project. Manfred's web site is at: http://home.t-online.de/home/MHuber/ ] ----- Original Message ----- From: Thom Mackris / Joan Panzella Sent: Monday, January 31, 2000 10:18 PM Subject: Re: Teres-Motor&Supply All, I'm forwarding the following comments from Manfred Huber regarding our motor supply. We have truly "scored" today, between Allen hopping on board, and now Manfred's comments. Cheers, Thom ----- Original Message ----- From: Manfred Huber To: Thom Mackris / Joan Panzella Sent: Monday, January 31, 2000 1:06 AM Subject: Re: [JN] Teres Turntable - A Group Project Thom, >Currently, our plan is to determine the order count by the middle of >February in order to establish a price. We hope to have the bearings and >platters machined by the middle of March. I own a Scheu turntable and use it with a Maxon DC motor. While these Motors work very well when powered by a good voltage source you still have to constantly adjust the voltage to get the right speed. This is due to changing power requirements of the bearing at varying temperatures and other such side effects. This is the reason I have built a 'intelligent' supply. The output voltage is controlled by a microcontroller (Atmel 89C2051) and a serial 12Bit ADC. The controller measures the rotational speed by a stroboscopic disc which is attached to platter. There are two control algorithms implemented. The first is a relatively fast PI controller which brings the platter quickly up to speed. After the speed has stabilized the controller automatically switches to a *very* slow integrative algorithm that holds the desired speed. This second algorithm can only change the output voltage at a rate of some tens of millivolts per minute. The supply sounds exactly the same as a good voltage source but with the added benefit of automatically maintaining the correct speed. Due to the microcontroller I had the opportunity to implement some nice features: You can start the motor by manually applying a small push to the platter. In the same fashion the motor can be stopped by manually speeding down the platter. After 40 minutes of undisturbed operation the motor is automatically stopped to protect the needle. The speed can be set to 33/45 RPM by a small push button. I have included the schematic, source code, stroboscopic disk and hex file in this mail, I hope you don't mind the bandwidth. Strobo.gif is the Stroboscopic disc. It is intended to be printed on a 600dpi laser printer. The disk has to be attached to the back side of the platter. I use self adhesive tape (the type that is sticky on both sides) for this purpose. U7 in the schematic is a small reflective interrupter working with UV light. This device is to be mounted in between the record player chassis and the platter with about 2mm distance to the stroboscopic disc. (self adhesive tape again) Let me know if I can be of any further help. Regards Manfred ----- Original Message ----- From: Jeremy Epstein > This is the reason I have built a 'intelligent' > supply. > > Due to the microcontroller I had the opportunity > to implement some nice > features : I'll say you did! These luxury items will raise the bar from "cool project" to "de luxe component" in short order. As a fan of convenience, this is welcome news. Thanks for getting involved Manfred, you are sure to be a big help. To others on the Teres list - Manfred is a very experienced and sophisticated designer and EE (as if you needed *me* to tell you that!) He has sent me some interesting circuits before, and they most definitely worked as advertised. We are very lucky to have his input IMHO, he designs by Einstein's rule : "As simple as possible, but no simpler." -j Jeremy, thanks a lot for your praise, it is very much appreciated! As we say around here: I'm cooking with water just like everybody else. >Thanks for getting involved Manfred, you are sure to be a big help. To be honest I don't want to get too involved with the turntable in itself. My Scheu is working well and already I have too many other projects running. I'm sure that my solution is not to everybody's taste but those who are interested are welcome to contact me and I will sure help to get the controler up and running. If there is enough interest (email me!) then I will write an article on the motor control unit and put it up on my website. (http://home.t-online.de/home/MHuber) Best regards to all of you Manfred ------------------ Manfred Huber MHuber@t-online.de ------------------ ----- Original Message ----- From: Igor Kuznetsoff Sent: Tuesday, February 01, 2000 1:52 PM Subject: Re: Teres-Motor&Supply Welcome, Manfred! This is exactly the P.S. (our possibility #3 by the time it got numbered) that I have urged several times, because I know how unstable speed is without active, automatic correction. This is precisely what we need, and now that a working option on this is available to us, my suggestion is to not consider any less ! I would simply agree with Jeremy that this would be de luxe, if I didn't think it downright necessary. Igor -----Original Message----- From: jhlane [mailto:jhlane@email.msn.com] Sent: Tuesday, February 01, 2000 8:18 PM Subject: Re: Teres: Subchassis & Armboard [Editor's note, Jon had just joined the list, after Manfred had made volunteered to contribute - he was unaware of the direction that the project was taking ] Group- One last note for today that may help in leiu of my finding the data on that casting compound: 1. A possible drive belt source. Barry Industrial Corp., 1156 N. Batavia St, Orange CA 92667. (714)639-4602. Mine is an old brochure but if Barry is still around those parts you may find all manner of instrumentation belting from plastics (Mylar and Kapton) to the various rubbers. I understand a few homebrewers are using old magnetic tape for 'table drive belts, so... 2. You probably know this but a good source for a fine precision ac motor is Hurst Mfg. Corp. Box 326, Princeton IN. (812)385-2564. Ask for the Honey Bee or the Mini Bee. These are (were) outside-rotor, balanced ac synchronous motors. Quiet enough and when driven with a small amplifier, dead on. Used one once about ten years back on a couple of 'table projects. Again, apologies if the motor and drive electronics have already been selected for THIS project; probably, a dc motor and supply electronics have been considered already. 3. There are good surplus houses with inventories of precision dc motors. If you need contact info for either Nebraska Surplus or C&H Sales, either search the web or contact me. Respectfully, Jon Lane ----- Original Message ----- From: Mackris, Thom G. Sent: Wednesday, February 02, 2000 10:27 AM Subject: RE: Motor Hi Jon, With respect to motors, we seem to be on a DC path, but once again - the dialog is open to conversation. You'll note the main reasons for DC on the web page (no time to pull it up now). Merrill (as well as AR's) use a Hurst AC syncronous motor. This is certainly not my area of expertise (that area would be typing ), and I encourage your comments. It appears that the big-hitters have all settled on DC. I suspect that the barrier to DC are among other areas the issue of controlling drift that Igor touched upon. Having Manfred's and Allen's genius on this project certainly knocks down these barriers. This is by *no* means a closed dialog. Belts are an interesting area. Have you seen the "Turn Your Table" article about the Platine Verdier in Sound Practices (Issue 10??). He settled on recording tape, figuring that the motor & drive was so superior that he didn't need a rubber belt for isolation. Cheers, Thom ----- Original Message ----- From: Manfred Huber Sent: Wednesday, February 02, 2000 12:42 PM Subject: Re: Teres-Motor&Supply Igor, fellow list members, so far three people from the list have shown interest in my motor controller. Maybe we get something going. It would be nice if somebody out there would be willing to make a PCB for the circuit. I'm not into homebrewing PCBs. One thing that has to be said: I don't want to sound like a smart ass that comes into your project late and then tries to shove his solution down your throats. So take everything I say with a grain of salt. I think that there will not be a single solution to the motor unit problem. Some may want to go with my approach while others may want something different for several reasons. Please continue to discuss other solutions to the motor problem. Here is my contribution to this discussion: The combination of the motor and the rotating mass forms a second order system that has its own resonance frequency. If there is not enough damping then the rotational speed of the platter will start to oscillate around this resonance point. There are several to ways to control the damping, to name two: - By changing the mechanical friction (using different kinds of oil in the bearing etc) This changes only the damping. - By changing the power (or strength) of the motor. This is what happens when you modify the diameter of the pulley. This affects the resonant frequency and the damping at the same time Lately I have thought about the following: The strength of the motor can also be controlled by the changing the internal resistance of the motor power supply. The higher the impedance of the PSU the weaker the motor and the lower the resonant frequency and the higher the damping. A motor PSU with zero output impedance is only one of many valid possibilities and not necessarily the best. How about a PSU which allows to adjust its internal impedance from about several hundred Ohms over zero to about -50 Ohms by a POT? (right, minus 50. This allows for compensation of the copper resistance of the coils inside the motor) Note that this has nothing to do with the microprocessor control. The uP just puts out the set point for the voltage regulator circuit built around the AD820. Its this regulator circuit that has to be changed. What do you think? Regards Manfred ----- Original Message ----- From: Stewart Ono Sent: Wednesday, February 02, 2000 12:57 PM Subject: Re: Teres-Motor&Supply Manfred: I love the idea of a variable impedance. I had a conversation with Harry Weisfield about his older PSU, where mine would need to be kick started for 45 rpm operation. He explained that the minimal voltage gave the best performance and that sometimes the minimal setting for 33 was not enough for 45. I adjusted the pot to give a 45 rpm start but did notice that at 33 detail was obscured and turned it back down as I use 45 infrequently. Your idea is a great one and would give the user some flexibility to get the maximum out of the TT. Regards, Stu ----- Original Message ----- From: Jeremy Epstein Sent: Wednesday, February 02, 2000 12:58 PM Subject: Re: Teres-Motor&Supply Manfred Huber wrote: > How about a PSU which allows to adjust its internal impedance from about several > hundred Ohms over zero to about -50 Ohms by a POT? > What do you think? I think you're a smartass . . . oops, no, you said you weren't. Seriously, though, Manfred, it's clear you have been working on this problem in a sophisticated way for a while and I for one am happy you are ahead of us. That's not "smartass," that's "prior art." I think from a practical sense, if the control circuit can be made to achieve a resonant frequency that is on the order of minutes and whose variation is very small, this would be sufficient to MY listening needs. Control to this extent (but with some degree of flaws) would be more enjoyable in the long run for me than having to do manual (and ultimately imprecise anyway) adjustments on my own every time I fired my turntable up. -j -- ----- Original Message ----- From: Schei, Kenneth Sent: Wednesday, February 02, 2000 1:23 PM Subject: RE: Teres-Motor&Supply Manfred: Add me to the list of those interested in your motor controller. I''ve downloaded your schematic and my first thought was "we should do a PCB for this." PCBs would be great if there's more than a few of us interested. My son has etched some boards in the past (with variable results) and it takes some skill and experience to do it right. I don't know if he would be able to help us. Does anyone on the list have PCB experience? Ken Ken Schei, P.E. Project Engineer Antarctic Support Associates Email address: scheike@asa.org Phone: 303-643-0163 ----- Original Message ----- From: Chris Brady Sent: Wednesday, February 02, 2000 1:32 PM Subject: Re: Teres-Motor&Supply Manfred, Based on the discussion so far I would guess that most if not all of those on the list would like to implement your controller if it could be done without undue expense and/or labor. If we were to pool our efforts we could make this into a simple turn-key solution that would hopefully be within the abilities and budget of everyone in the group. We could make circuit boards or go as far as putting together a complete parts kit. Manfred, do you have a rough idea of the parts cost? What resources are required to generate the micro-code? I have some software for creating circuit board layouts. I have not used it yet but I will do an evaluation. Chris ----- Original Message ----- From: Chris Brady Sent: Wednesday, February 02, 2000 1:40 PM Subject: Re: Teres-Motor&Supply [Editor's Note: Ron Welborne had subsequently replied that he would be willing to etch high quality boards for the project at a very reasonable price. This post appears later in this digest]. I etched some PC boards years ago with good results. It requires a modest equipment and supplies purchase and some experimentation to get the process down. Not worth it for one or two boards. But for a larger number it would be a real boon. We could also have boards professionally done but this is expensive for small quantities. But if everyone building a turntable we interested the price may be acceptable. Chris ----- Original Message ----- From: George Munger Sent: Wednesday, February 02, 2000 4:15 PM Subject: Re: Teres-Motor&Supply For the record, I am very interested in a quality controller and board. GM ----- Original Message ----- From: Igor Kuznetsoff Sent: Thursday, February 03, 2000 12:33 AM Subject: Re: Teres-Motor&Supply Manfred, I think that is a really fine idea that needs to be pursued. It makes plenty of sense to me. I've fooled around with electrical damping control of speaker motors (as opposed to the more conventional acoustical techniques) a bit, and was able to improve on overhang (ringing) as well as parasitic driver/room/driver resonance excitation. Certainly this should work similarly here. Using a pot to set the impedance sounds workable, though I suppose we could get really over the top crazy and consider sensing circuitry that could detect/regulate oscillations in torque/current demand (which I would guess would be the expression of the feedback of the speed oscillation resonance) via automatic regulation of the PSU internal impedance, if this could be done without exciting a secondary "hunting" or oscillation in the impedance regulation itself. Am I making any sense, and would such a thing be a practical endeavour? Oh, and while I used the grandiose sounding "we", I *really* meant *you*, as I do not have any expertise in motor control. See how dangerous it is to "shove" against negative resistance? Whether or not you take this rambling seriously, I am quite happy about your involvement ! Igor ----- Original Message ----- From: Manfred Huber Sent: Friday, February 04, 2000 5:35 AM Subject: Re: Teres-Motor&Supply Fellow Listmembers, meanwhile it looks like there is quite a bit of interest on the motor controller so I will start to redesign the circuit now. This will take some time for experimenting and building a prototype. Some questions: - What's the time frame - Has the group already settled on a specific motor? - Maybe somebody can call the US office of Maxon (see www.maxon.ch) and ask for pricing and availability of the type 110189 motor. In order to keep the traffic low I want to comment on several emails regarding the subject in just one reply: Igor Kuznetsoff wrote: >I suppose we could get really over the top crazy and consider >sensing circuitry that could detect/regulate >oscillations in torque/current demand (which I would >guess would be the expression of the feedback of the >speed oscillation resonance) via automatic regulation >of the PSU internal impedance, This is what is called a self-adaptive controller, an area in which I unfortunately have no experience. I guess it would take me months to work out something like this. Even if I had the time: How does the controller know which amount of damping sounds best? In fact I'm not sure if the addition of a variable impedance is worth the trouble. Remember we can achieve a similar result by changing the pulley diameter. I don't want to over engineer things. I will do some experimentation in this regard. Thom Mackris wrote: >I had not put you on my e-mail list until now, not wanting to overburden you >with e-mails that this project might generate (especially the ones not >related to motor controller design). Not a problem Thom, consider me a normal list member, no special treatment necessary. Just be prepared that I will not read every mail on the design of the turntable itself. Chris brady wrote: >If we were to pool our efforts we could make this into a simple >turn-key solution that would hopefully be within the abilities >and budget of everyone in the group. We could make circuit boards >or go as far as putting together a complete parts kit. A PCB is definitely the way to go. I guess that building the circuit on a prototype PCB may be too hard for someone who has no experience in this field. >Manfred, do you have a rough idea of the parts cost? I estimate the parts cost at about $50. This does not include the PCB, Motor and housing. >What resources are required to generate the micro-code? This is the hardest part. You would need a very expensive C compiler (Keil) to generate the binary image and a programmer to get the program into the controller. The only solution I can see is that I program a few controllers and send them to one list member in the US who does the distribution to other members and collects the money. It would be even better if somebody else on the list had a programmer suitable for the AT89C2051. I would provide the binary image of the software and the parts could be bought and programmed in the US. This would save the expenses for shipping and customs. Jeremy Epstein wrote: >I think from a practical sense, if the control circuit can be made to >achieve a resonant frequency that is on the order of minutes and whose >variation is very small, this would be sufficient to MY listening needs. I think that the resonance frequency (motor/platter) is not very important but the damping is. This is because the signal is multiplied with the rotational speed. If the speed is not constant you will always hear it. The only choice we have is too add enough damping to avoid the excitation of the resonance. The microprocessor speed control loop is *very* slow. It has no chance to oscillate. One thing I did not mention up to now: This controller is designed to ensure the long term stability of the rotational speed. It is not meant as a cure for mechanical problems. I chose to not implement fast controller that tries to compensate for friction forces that change over one turn of the platter and the like. IMHO this kind of problems are better solved in the mechanical domain. Enough babbling done for today Regards Manfred ----- Original Message ----- From: Jeremy Epstein Sent: Friday, February 04, 2000 7:49 AM Subject: Re: Teres-Motor&Supply Manfred Huber wrote: > > Fellow Listmembers, > > meanwhile it looks like there is quite a bit of interest > on the motor controller so I will start to redesign the circuit now. > This will take some time for experimenting and building > a prototype. Thank you! > - Has the group already settled on a specific motor? I think there are some specific motors one list member has recommended (help me!) also several of us picked up a second-best solution, a decent/cheap surplus motor. I can send you my own surplus motor for experimentation if that will help. > - Maybe somebody can call the US office of Maxon > (see www.maxon.ch) and ask for pricing and availability > of the type 110189 motor. You would recommend this one, then? > A PCB is definitely the way to go. I guess that building the circuit > on a prototype PCB may be too hard for someone who has no experience > in this field. I have not made PCB's but I have read enough about it to THINK I could do it with some practice. I don't have the sense that, once they are drawn, burning them is very difficult, it just takes a little technique and some NASTY chemicals. I guess I am saying, if no one else is interested in learning how to do this, I am curious enough to give it a try - just be aware that learning-curve costs will be included if I do the boards. > >Manfred, do you have a rough idea of the parts cost? > > I estimate the parts cost at about $50. This does not include the > PCB, Motor and housing. This just keeps getting cheaper and cheaper . . . . I have seen small-run PCB's in the 30 dollar range, which I think included markup. I guess what I am saying is, we could probably turn out ten good-quality ones for between 100-200 dollars if all goes reasonably well. This is just a guess, but I can look into it. Anybody know where to get good quality board material on the East Coast of the USA? > >What resources are required to generate the micro-code? > > This is the hardest part. You would need a very expensive C compiler (Keil) > to generate the binary image and a programmer to get the program > into the controller. > > The only solution I can see is that I program a few controllers and send them > to one list member in the US who does the distribution to other members and collects > the money. Again, if no one else is eager to do this I could probably do it. I guess I'm heading towards "controller kit guy" uh oh . . . . > It would be even better if somebody else on the list had a programmer suitable > for the AT89C2051. I would provide the binary image of the software and the parts > could be bought and programmed in the US. This would save the expenses for > shipping and customs. We should probably investigate that, each of us here knows all sorts of geeks, er, engineers. > Jeremy Epstein wrote: > > >I think from a practical sense, if the control circuit can be made to > >achieve a resonant frequency that is on the order of minutes and whose > >variation is very small, this would be sufficient to MY listening needs. > > I think that the resonance frequency (motor/platter) is not very important > but the damping is. This is because the signal is multiplied with the rotational speed. If the > speed is not constant you will always hear it. The only choice we have is too > add enough damping to avoid the excitation of the resonance. I'll take your word, this beyond my level of understanding of mechanical systems! I may have said it wrong, but what I meant was, if the speed wanders by a very small amount over the course of a minute or so, I can live with that. Knowing you, the thing will perform better than that anyway. > This controller is designed to ensure the long term stability of the rotational speed. > It is not meant as a cure for mechanical problems. I chose to not implement fast controller > that tries to compensate for friction forces that change over one turn of the platter and the like. > IMHO this kind of problems are better solved in the mechanical domain. I am quite sure the rest of the group agrees with this statement 100 percent Manfred, that seems to be sort of the whole point of the super-bearing and giant high-inertia platter. > Enough babbling done for today Your babbling is pretty darn cogent if you ask me, don't think twice, it's alright. -j -- ========================================= Jeremy Epstein .........jepstein@shwd.com ========================================= ----- Original Message ----- From: Mackris, Thom G. Sent: Friday, February 04, 2000 9:28 AM Subject: RE: Teres-Motor&Supply Hi Manfred, We are deeply in your gratitude. The motor we were originally playing with was intended to be a first swipe. It is a 24 Volt DC Pittman motor. I had found a dozen of these in a surplus electronics house early on in the project. Although it is robust, when Ken Schei and I powered it up and compared it to his Faulhauber motor, it became apparent that we would eventually go in the direction of a quieter motor. It's quite obvious to me that the sort of effort involved in generating micro code for the controller circuit should not be wasted on a short term solution like the Pittman motor. We are following the trail that you have broken for us. It is my opinion, that we should follow your lead with respect to the Maxon motor, for reasons of (a) quality and (b) future replacability. We all need to get out feelers out to see if we can find a "programmer suitable or the AT89C2051". Thanks, Thom ----- Original Message ----- From: Steve Zettel Sent: Saturday, February 05, 2000 6:52 PM Subject: Re: Teres-Motor&Supply Very well put, Thom. I am with you 100% on this regarding the motor. The Maxon or the Faulhauber is the direction I would like to go. Steve Z ----- Original Message ----- From: Igor Kuznetsoff Sent: Friday, February 04, 2000 2:07 PM Subject: Re: Teres-Motor&Supply [Igor Kuznetsoff had previously written]: >>I suppose we could get really over the top crazy and consider >>sensing circuitry that could detect/regulate >>oscillations in torque/current demand (which I would >>guess would be the expression of the feedback of the >>speed oscillation resonance) via automatic >> regulationof the PSU internal impedance, [to which Manfred responded]: --- Manfred Huber wrote: > This is what is called a self-adaptive controller, an area > in which I unfortunately have no experience. I guess it > would take me months to work out something like > this. > > Even if I had the time: How does the controller know which > amount of damping sounds best? [to which Igor now responds]: It wouldn't have to. I had it in mind to use the pot to set the bias level manually, and depend on the adaptive circuitry to provide improved stability via automated impedance damping, in addition to the normal voltage driven speed control. I was attempting to consider a possible means of effecting reactive damping of torque oscillaton, as opposed to speed fluctuation (as in "horsepower" vs. "torque" in an automotive engine, more or less). By setting the damping bias level with a pot, we could let our ears do the deciding, while such a circuit would do the reactive "fine trimming" to account for torque cycling resulting from a variety of things running from cyclical (microscopic) belt stretching to program dependent varying stylus drag. Maybe even vagrant air currents :-) . But these are extremely fine points. > In fact I'm not sure if the addition of a variable > impedance is worth the trouble. I agree. I was only musing, you needn't take this seriously. It may not be practical. >Remember we can achieve a similar result by changing >the pulley diameter. Only there would be no reactive stabilization, which could result in improved pitch stability & definition. >I don't want to over engineer >things. I will do some experimentation in this regard. That's sensible. I've just never been into dragging sand to the beach, using well-worn paths. I'm a restless believer in progress, improvements through breaking new ground. It is certainly your call, you're the expert, I'm just making trouble, probably. Igor ----- Original Message ----- From: Chris Brady Sent: Friday, February 04, 2000 11:46 PM Subject: Re: Teres-Motor&Supply Manfred, For the time frame I would expect that most of us will move forward fairly rapidly when we have the bearing and platter in hand. Right now that is looking like late March. I think that mid April would be the soonest that anyone would be able to put a controller to use. I will probably just use a simple regulated power supply in the short term. You mention that you need to redesign the circuit. I looked at the schematic you provided and was duely impressed. I am curious, what changes do you have in mind? I was able to find an inexpensive ($30) kit for a 8051 programmer so we should have no problem programming the controllers here in the US. I also looked around for C compilers and for assemblers. I found a C compiler for $155 and an assembler for $45. I don't know what the current state of the software is, but I would be glad to help if possible. I am proficient in both C and assembler. Years ago I did a lot of development work with micro-controllers so please let me know if I can help. We appreciate your willingness to make your design available to us. Chris [Manfred had previously written]: > This is the hardest part. You would need a very expensive C compiler (Keil) > to generate the binary image and a programmer to get the program > into the controller. > > The only solution I can see is that I program a few controllers and send them > to one list member in the US who does the distribution to other members and collects > the money. > > It would be even better if somebody else on the list had a programmer suitable > for the AT89C2051. I would provide the binary image of the software and the parts > could be bought and programmed in the US. This would save the expenses for > shipping and customs. > > I think that the resonance frequency (motor/platter) is not very important > but the damping is. This is because the signal is multiplied with the rotational speed. If the > speed is not constant you will always hear it. The only choice we have is too > add enough damping to avoid the excitation of the resonance. > > The microprocessor speed control loop is *very* slow. It has no chance > to oscillate. > > One thing I did not mention up to now: > > This controller is designed to ensure the long term stability of the rotational speed. > It is not meant as a cure for mechanical problems. I chose to not implement fast controller > that tries to compensate for friction forces that change over one turn of the platter and the like. > IMHO this kind of problems are better solved in the mechanical domain. > > Enough babbling done for today > > Regards > Manfred ----- Original Message ----- From: Chris Beck Sent: Saturday, February 05, 2000 6:35 AM Subject: Re: Teres-Motor&Supply Hi, gang. Regarding the PCB, even lowly Radio Shack has a kit to etch your own board. The trick is getting the artwork done. I beleive the process is straightforward after that. I seem to remember that once the pattern is complete, you copy it onto a transparency, and make two, so you can double up for better quality of exposure. Tape it over the raw board and expose to light. Then, you etch the board, removing the exposed areas of copper, leaving your traces. Then, you drill all the holes, and voila', PC board. I also remember a company in the US called FAR Circuits, that offered hundreds of different small production PC boards for Amateur Radio hobbiest projects out of the big magazines such as QST. The pricing was VERY reasonable for stuff that could not have been high volume. I'll have to dig up their address. I have purchased boards from them years ago, and found them to be of good quality. Chris Beck ----- Original Message ----- From: Manfred Huber Sent: Saturday, February 05, 2000 8:34 AM Subject: Re: [teres] Re: Teres-Motor&Supply Chris, >Right now that is looking like late March. I think that mid April would >be the soonest that anyone would be able to put a controller to use. The new design will be available much earlier then this but it will also take time to build the PCB get materials etc. >You mention that you need to redesign the circuit. I looked at the >schematic you provided and was duely impressed. I am curious, >what changes do you have in mind? I have already designed a new, more elegant circuit for the part of the controller that does the signal conditioning for the reflective interrupter. Back then when I designed the first circuit I used the LM311 because I had it on hand. The new design will use a part that is more suitable to the task. There may also be some changes to the voltage regulator built around the AD820. >I was able to find an inexpensive ($30) kit for a 8051 programmer so >we should have no problem programming the controllers here in the >US. Great, have you veryfied that it can program the AT89C2051? This is a flash device while most other programmable MCS51 type controllers are eprom based. There is a $75 programmer at http://www.proaxis.com/~iguanalabs/2051prog.htm >I also looked around for C compilers and for assemblers. I found a C >compiler for $155 and an assembler for $45. I don't know what the current >state of the software is, but I would be glad to help if possible. I am >proficient in both C and assembler. Is there a demo for that compiler? The compiler I use is the most efficient available today. The problem is that there are only about 150 bytes (out of 2k) of program memory free. The new compiler has to generate very tight code or it will run out of memory. >Years ago I did a lot of development >work with micro-controllers so please let me know if I can help. Great news! I sure can use some help: There is a free C51 compiler at http://www.geocities.com/ResearchTriangle/Forum/1353 You (or other computer literates out there) could try to port my software to this compiler. If the works out then everybody who is interested could do his own modifications to the controller software. I have put up a slightly revised version of the source code and schematic to my homepage: http://home.t-online.de/home/MHuber/DCMOT_10.ZIP (preserve case!) This archive contains everything needed to build the controller. It can be compiled with Keil C51 V4 or later (I use 5.1 at the moment) There is also a precompiled version included (bin and hex) This version is still lacking any documentation! Please contact me if you have questions. Regards Manfred ----- Original Message ----- From: Manfred Huber Sent: Saturday, February 05, 2000 8:34 AM Subject: Re: [teres] Re: Teres-Motor&Supply Chris, >Right now that is looking like late March. I think that mid April would >be the soonest that anyone would be able to put a controller to use. The new design will be available much earlier then this but it will also take time to build the PCB get materials etc. >You mention that you need to redesign the circuit. I looked at the >schematic you provided and was duely impressed. I am curious, >what changes do you have in mind? I have already designed a new, more elegant circuit for the part of the controller that does the signal conditioning for the reflective interrupter. Back then when I designed the first circuit I used the LM311 because I had it on hand. The new design will use a part that is more suitable to the task. There may also be some changes to the voltage regulator built around the AD820. >I was able to find an inexpensive ($30) kit for a 8051 programmer so >we should have no problem programming the controllers here in the >US. Great, have you veryfied that it can program the AT89C2051? This is a flash device while most other programmable MCS51 type controllers are eprom based. There is a $75 programmer at http://www.proaxis.com/~iguanalabs/2051prog.htm >I also looked around for C compilers and for assemblers. I found a C >compiler for $155 and an assembler for $45. I don't know what the current >state of the software is, but I would be glad to help if possible. I am >proficient in both C and assembler. Is there a demo for that compiler? The compiler I use is the most efficient available today. The problem is that there are only about 150 bytes (out of 2k) of program memory free. The new compiler has to generate very tight code or it will run out of memory. >Years ago I did a lot of development >work with micro-controllers so please let me know if I can help. Great news! I sure can use some help: There is a free C51 compiler at http://www.geocities.com/ResearchTriangle/Forum/1353 You (or other computer literates out there) could try to port my software to this compiler. If the works out then everybody who is interested could do his own modifications to the controller software. I have put up a slightly revised version of the source code and schematic to my homepage: http://home.t-online.de/home/MHuber/DCMOT_10.ZIP (preserve case!) This archive contains everything needed to build the controller. It can be compiled with Keil C51 V4 or later (I use 5.1 at the moment) There is also a precompiled version included (bin and hex) This version is still lacking any documentation! Please contact me if you have questions. Regards Manfred ------------------ Manfred Huber MHuber@t-online.de ------------------ ----- Original Message ----- From: Ron Welborne Sent: Saturday, February 05, 2000 10:22 AM Subject: Re: Teres-Motor&Supply I have circuit board layout software and could do the artwork for the boards. If you get enough orders to do a run of approximately 25 boards, then the price to have them professionally made would be less than $10 each. At this price the boards would be FR4 glass epoxy with solder-plated 2oz. copper. For silkscreening, add another ~$3 per board. A run of 15 boards would put the price at around $15-$18 each. Ron Welborne Labs wlabs@ix.netcom.com ph: 303.470.6585 fax: 303.791.5783 website --------------- www.welbornelabs.com ----------------- ----- Original Message ----- From: Chris Beck Sent: Saturday, February 05, 2000 1:43 PM Subject: [teres] Re: Teres-Motor&Supply That's about what I was figuring, Ron. Thanks for the input! This would, IMHO, be the way to go for us if we decide to all use the controller idea, which to me, seems pretty slick. Chris Beck