I was at what I might mistakenly call the Hoover Dam. As the tour ended I asked had they had problems with bearings? The guy look surprised and said yes they had. They now use exactly what they used in the early days. The Dam looks exactly as if built yesterday. We visited after the CES hi fi show. There was a locomotive museum on the way. It was closed. We chanced looking arround. Great to see 1940's diesel engines. I saw a 1940's turbo charger. I now learn they came from the 1920's or before.
SAE 20 or 30 should be good. I dare say olive oil changed every 6 months could work. Less so in the motor. Esso said the oil we requested could be eaten as far as they knew. The guy said that we shouldn't try as it was a theory and had never been tested. His arguement was if it could be eaten it would suit us. What causes us trouble will cause phosphor bronze trouble. Phosphor bronze looks very last century. Just try to better it or take short cuts using it. It is the better engineering solution that is suspected to be the worst. You can always tell a true engineer as they know that without asking. I have tried many plastics. They work OK. Bronze seems better and can be ultra low cost. You will never easilly exceed a bronze pressed bearing that might cost 50 cents. Never force them into a space as the fraction of an inch will ruin what is so good about them. When matched to a stock shaft they simply work. I source my shafts from Switzerland via Thorens ex parts lady. They cost a fortune. The phosphor bronze is the standard grade. And yet even though a mirror finish it's the shaft that can always be better. As far as I know this exceeds any part Thorens used.
SAE 20 or 30 should be good. I dare say olive oil changed every 6 months could work. Less so in the motor. Esso said the oil we requested could be eaten as far as they knew. The guy said that we shouldn't try as it was a theory and had never been tested. His arguement was if it could be eaten it would suit us. What causes us trouble will cause phosphor bronze trouble. Phosphor bronze looks very last century. Just try to better it or take short cuts using it. It is the better engineering solution that is suspected to be the worst. You can always tell a true engineer as they know that without asking. I have tried many plastics. They work OK. Bronze seems better and can be ultra low cost. You will never easilly exceed a bronze pressed bearing that might cost 50 cents. Never force them into a space as the fraction of an inch will ruin what is so good about them. When matched to a stock shaft they simply work. I source my shafts from Switzerland via Thorens ex parts lady. They cost a fortune. The phosphor bronze is the standard grade. And yet even though a mirror finish it's the shaft that can always be better. As far as I know this exceeds any part Thorens used.
Looked through the above vendor's items and was somewhat amazed to see a good selection of carbon items. Whilst not on the subject of oils, this technology was introduced to Europe by Be Yamamura. [ART [Italy] were the importers and wholesalers of similar items and Yamamura cables].
A block of carbon placed under the main bearing in such a manner as to support 70-80% of the weight of the complete motor unit, whilst the normal fixing studs support the remainder - will do wonders to clean up the sound of any TT. Obviously works as a 'drain' and the effect could I imagine be increased by experiment with various base boards under the carbon. I learned this directly from Be who used a 401 Garrard as a workshop beast of burden.
I tried that years ago and liked how easy it was to make. The sample came from the very naughty part of Harwell. When I asked if it was OK my boss said a good question as it came from exactly the place where that question should be asked. I felt is lost some bass impact. It stood up to use very well. I used a pyrometer window with it as they are cheap and of very high quality. A 10 mm type about 3 mm thick.
It should be very good. Garrard published ideas for transcription turntables about in 1953. This said why the direct drive 201 needed upgrading. Glass was said to be the reference material to test against. Graphite looks like a sheet of electrons so unlikely to be bettered. It only took me 10 minutes to make the parts. It could have been with woodworking tools, it's that easy. The graphite shaped like a 401 thrust and the 301 shaft super-glued to the pyrex glass. The squareness set in the lathe which had been recently checked by the now head of engineering science at Oxford ( He has Vincent and Scot motorcycles so knows similar stuff ). Even if it had been off it wouldn't have mattered as this design allows for some error ( not the Garrard, that is very highly accurate ). Using the lathe end stock the rotational wobble is set as the glue goes off. I used a damaged 301 spindle as it was also an idea for rescuing them.
The TD124 would be easy. It just needs a flat piece of motor brush grade graphite ( vacuum cleaner is easiest ). Any grapite that gets into the oil will be harmless as best I know. I suspect 3mm thick would be OK. I did try magnets. It didn't sound right. Mixed with graphite might.
The TD124 would be easy. It just needs a flat piece of motor brush grade graphite ( vacuum cleaner is easiest ). Any grapite that gets into the oil will be harmless as best I know. I suspect 3mm thick would be OK. I did try magnets. It didn't sound right. Mixed with graphite might.
Hello again,
So I want input from users and think this thread is the best; I have a TD-124, cleaned and restored by Gregory Metz, it is quiet and keeps speed dead on no matter what voltage I throw at it. Would have loved to restore it myself but a small apartment in Manhattan with a 2 year old is just not the ideal place to have parts laying around, so my future means any work the table needs will have to outsourced. In any event this is not the reason for writing, it has to do with which tonearm to get. It will be an SME as I have an SME IV on my VPI HW-19 and absolutely love everything about, in particular the great ease of setup. I have toyed with the idea of swapping it on the TD-124 and trying it out but it is so dialed in on the VPI that I don't want to change the settings. So, which arm should I get for the Thorens another SME IV or the M2-9r? Mr. Keyser at smetonearms in Canada says the M2-9r would be the best candidate as I can swap headshells, and it has a threaded collet that allows precise horizontal tracking angle, now I do love that I can swap cartridges with the idea in the future of perhaps trying some of those SPU cartridges. But I do love the fixed and rigid headshell of the IV. My reason for this fixation is due to my first ever turntable I owned, many years ago a TD-166, which unbeknownst to me, over frequent use the headshell managed to shift and damaged my records. Mr. Keyser said not to worry with the M2-9r it is so tight that it would only possibly move after thousands of usages, still that worries me a little, plus the IV is I believe superior, but of course I already have one so…….What would you guys do?
So I want input from users and think this thread is the best; I have a TD-124, cleaned and restored by Gregory Metz, it is quiet and keeps speed dead on no matter what voltage I throw at it. Would have loved to restore it myself but a small apartment in Manhattan with a 2 year old is just not the ideal place to have parts laying around, so my future means any work the table needs will have to outsourced. In any event this is not the reason for writing, it has to do with which tonearm to get. It will be an SME as I have an SME IV on my VPI HW-19 and absolutely love everything about, in particular the great ease of setup. I have toyed with the idea of swapping it on the TD-124 and trying it out but it is so dialed in on the VPI that I don't want to change the settings. So, which arm should I get for the Thorens another SME IV or the M2-9r? Mr. Keyser at smetonearms in Canada says the M2-9r would be the best candidate as I can swap headshells, and it has a threaded collet that allows precise horizontal tracking angle, now I do love that I can swap cartridges with the idea in the future of perhaps trying some of those SPU cartridges. But I do love the fixed and rigid headshell of the IV. My reason for this fixation is due to my first ever turntable I owned, many years ago a TD-166, which unbeknownst to me, over frequent use the headshell managed to shift and damaged my records. Mr. Keyser said not to worry with the M2-9r it is so tight that it would only possibly move after thousands of usages, still that worries me a little, plus the IV is I believe superior, but of course I already have one so…….What would you guys do?
Go for the SME M2-9R (or even better the SME M2-12R). I have the 12" version and it sounds gorgeous with SPUs, especially since Thomas Schick seems to have forgotten my order which I placed in June 2014). However, the Old ortofon arms (RMG or SMG 212) are also excellent (had one of the SMG 212s).
The VTA-story that you have been told is highly unlikely: your cartridge would have had to be Seriously misaligned in order to make any impression on your records and anyway the slot in the socket allows for at least 5° misalignment as the diaameter of the pin in the sme socket is not standardized.
The VTA-story that you have been told is highly unlikely: your cartridge would have had to be Seriously misaligned in order to make any impression on your records and anyway the slot in the socket allows for at least 5° misalignment as the diaameter of the pin in the sme socket is not standardized.
I would slightly question the stabilty of the TD124 " regardless of voltage ". I understand what you are saying to be, as compared with many TD124's that are not giving their best. I have designed motors of this type. The classic text book statement was " The hysterisis motor will appeared to be synchronous at light loading ". The books then show how the motor works and do not say much about the very big advantage the hysterisis has. That is the " lock " is elastic. The eddy current brake is to allow very simple adjustment. When Garrard to cover 190 to 270 V ( 95 to 135 V ). It is not to correct 78 that needs 66 to 92 RPM at a guess.
I only say this as your well intentioned statement will drive people to think they have a defective turntable. Although I have not tested it I suspect 210 to 240 V = 0.2% or +/- 0.1 % when 220 V is centre ( best possible ). It can be infered that +/ 3 % if 190 to 270V. One thing that caused trouble when cutting LP's was to use quartz locked lathes with existing tape machines. This produced bad errors. When neither was quartz locked all the errors were common and thus zero error.
I only say this as your well intentioned statement will drive people to think they have a defective turntable. Although I have not tested it I suspect 210 to 240 V = 0.2% or +/- 0.1 % when 220 V is centre ( best possible ). It can be infered that +/ 3 % if 190 to 270V. One thing that caused trouble when cutting LP's was to use quartz locked lathes with existing tape machines. This produced bad errors. When neither was quartz locked all the errors were common and thus zero error.
I hope it isn't misleading, I was trying to make the point that feeding the table 110, 115 & 120 volts has shown a very small, minute change in speed. While I have a thicker Thorens mat and clamp on the table it is not a real world situation as there is no stylus drag to simulate a real world experience but the speed does run 33.5 +/- .03 but generally stays steady.
Thanks for your response right now leaning towards that one as well, the problem with the 166 wasn't the VTA but the azimuth on the headshell had moved and on certain high passages there was more crackling on loud passages when the vinyl mistracked with an entry level Grado. Maybe it was just the Grado and the arm not tracking properly but once I discovered that the headshell was too lose and was moving I promptly sold it and moved on, hence my apprehension with "loose" headshells but I have been reassured by Mr. Keyeser that this will not happen. Still a IV is a lovely arm.
How do you measure speed?
At least to +/- 0.3 RPM? I use a laser tach, which reads 2 decimal places so at best +/- 0.005 RPM. so the precision of the measurements (assuming a reading of 33.33 RPM is .01 X100/33.33 which is 0.03003 %). Synchronous AC motors rely on the frequency of the mains. Small variances can occur because of adjusting the mains voltage to various levels using auto-formers, resistors, etc. (at least if I can trust my memory)
As far as tonearms are concerned, it certainly appears that the M2-9R is a likely candidate if wanting to go that route. I do not need a removable headshell and do not foresee using that feature, although my SME 309 does have one. The SME tonearms are a joy to own and operate. The biggest hassle I had with mine was getting a mounting plate for my Oracle made. I ended up having a machinist modifying the existing board for the Oracle/SME combination. The only way to make it work was to have a custom block milled and threaded. Then cut the armboard to fit the SME. I now have what I consider to be a reference quality tonearm blank.
At least to +/- 0.3 RPM? I use a laser tach, which reads 2 decimal places so at best +/- 0.005 RPM. so the precision of the measurements (assuming a reading of 33.33 RPM is .01 X100/33.33 which is 0.03003 %). Synchronous AC motors rely on the frequency of the mains. Small variances can occur because of adjusting the mains voltage to various levels using auto-formers, resistors, etc. (at least if I can trust my memory)
As far as tonearms are concerned, it certainly appears that the M2-9R is a likely candidate if wanting to go that route. I do not need a removable headshell and do not foresee using that feature, although my SME 309 does have one. The SME tonearms are a joy to own and operate. The biggest hassle I had with mine was getting a mounting plate for my Oracle made. I ended up having a machinist modifying the existing board for the Oracle/SME combination. The only way to make it work was to have a custom block milled and threaded. Then cut the armboard to fit the SME. I now have what I consider to be a reference quality tonearm blank.
I need to remind people that the TD-124 motor is asynchronous and in normal use pole slips continuously, it is not tightly locked to the line frequency and indeed that is how one can vary motor speed by varying the load on the motor via an eddy current brake or similar. Variations in mains voltage do affect speed, but load and line frequency have a much bigger effect. Reducing line voltage sufficiently reduces torque which is what causes the speed to drop.
In fact the biggest problem I have with this motor is temperature related, bushing and lubrication dependent - cold motors run slow and the motor runs significantly faster when warm; some motors being more extreme than others, but in my experience a good motor will settle to the same speed time after time without need for further adjustment if the speed is set when fully warm. I have one motor that comes up to speed very quickly regardless of ambient temperature and one that does not. (I'm going to look at that motor again I think, but it is slated to be replaced with a 3 phase papst on 3 phase power so who knows how motivated I will be.)
In fact the biggest problem I have with this motor is temperature related, bushing and lubrication dependent - cold motors run slow and the motor runs significantly faster when warm; some motors being more extreme than others, but in my experience a good motor will settle to the same speed time after time without need for further adjustment if the speed is set when fully warm. I have one motor that comes up to speed very quickly regardless of ambient temperature and one that does not. (I'm going to look at that motor again I think, but it is slated to be replaced with a 3 phase papst on 3 phase power so who knows how motivated I will be.)
No laser tach, never got around to getting one just a crude rpm meter that I put on the platter to measure, will one day pay the $15 and order one. Will in all likelihood opt for the M2-9r as I already have a IV and like the vintage look of the M2-9r.
Don't trust your memory. You have much of this wrong.
the speed is 33 and one third (= 33.33 repeating) that is the same as 100 revolutions in 3minutes.
There is no point in measuring to +-0.005 if you don't know what speed you are aiming for.
You got this bit right.
Then you said
This is wrong. The synchronous motor locks onto the frequency and provided you don't overload the motor it stays locked onto the frequency irrespective of the supply voltage.
But there is a phase difference between the input current and the output shaft.
At no load the phase difference is very small. As the load increases the phase increases. As the load varies the phase error varies. This gives a small vibrational error in output speed. The rubber belt and the inertia of the table will smooth out these vibrations and hopefully one does not hear the motor vibrations.
Yes. That's why they are so good. The near synchronous at light loading is part of the magic. A true synchoronous is a close cousin of a stepper. Both step. The hysterisis motor has no obvious steps. Verdier speculated that stylus should <10 % of the load as compared with drag as best I remember. The drag both oil and eddy brake being desirable. I suspect I misunderstood as 10 % seems too much.
There was a understanding from the mid 1980's that class B amplifiers can raise above the mains due to the inductance of the same. I think I might have found a very simple way to prove that and a very spectacular one at that. I have often seen very high voltages when the wrong phase capacitor was selected for a synchronous motor. Never took much notice and nothing bad happened. Today I was testing a very large motor like the TD124 has for an industrial application. I can not say too much as I am being paid for this. For interest I ran a capacitor as a heat-less ballast in series. The motor was very troubled and reading 320V. I understand why but did not exspect the power output I got. The capacitor was the result of pretending the motor was a resistor as a ball park. As my girlfriend would say " don't try this yourself ". She always says one day it will be sheds in space. The bigger surprise was this was not far from ideal. Halving the capacitor value gives 120 V from 240 V. None of this is surprising except the power available. This looks to confirm class B could raise above mains. Thus a low distortion class B/G/H/D could sound better than PP class A when transistor. It also suggests output transistors need to be rated at double voltage. They often are for other similar reasons. The PSU cap designers must take this into account as they seldom fail. I am not worried about being wrong on this. Better to be wrong with safety in mind.
Again I feel the need to point out that these motors are ASYNCHRONOUS, and SIGNIFICANT pole slipping is inherent in normal operation. At nominal platter speed these motors are running perhaps as much as 6% or more BELOW synchronous speed. (Completely unloaded they run about 3% below synchronous speed typically)
A typical TD-124 is stated to have a speed adjustment range of +/- 3% from nominal, this is rarely achieved and usually ends up scewed significantly in one direction or the other. (Brake adjustment, temperature, line voltage and motor condition all play a role here.)
Can you hear me?
Asynchronous and good because they are. The motor I am working on is 1330 RPM @ 50 Hz 4 pole at a rated 5 watts output power. It would be 1500 RPM if a synchronous.That's book spec. I suspect it will be more when I use it as I won't be asking 5 watts. 1420 would be my guess.
The Garrard 501 is 6 mm shaft and 10.5 inch rim. 266.7/6 = 44.45 x 33.33 = 1481.7 RPM @ 52 Hz. 1424.7 RPM @ 50 Hz or about - 5%. The idler slip will be minimal. When a pulley was fitted it was 6.33 mm @ 50 Hz. The shaft is a better pulley. 401 and 301 had similar diameters. No two 301 motors were exactly alike.
Does anyone have the exact shaft size for a TD124 ( vernier would be good rather than supposed size )? I suspect it is less than 5mm ? I am 99% certain the bronze outers are off the shelf 5 mm. Garrard was 4.91 mm which was their own size. We suspect it was 5mm lapped. The outers were made by the company that made the London Taxi cabs.
The Garrard 501 is 6 mm shaft and 10.5 inch rim. 266.7/6 = 44.45 x 33.33 = 1481.7 RPM @ 52 Hz. 1424.7 RPM @ 50 Hz or about - 5%. The idler slip will be minimal. When a pulley was fitted it was 6.33 mm @ 50 Hz. The shaft is a better pulley. 401 and 301 had similar diameters. No two 301 motors were exactly alike.
Does anyone have the exact shaft size for a TD124 ( vernier would be good rather than supposed size )? I suspect it is less than 5mm ? I am 99% certain the bronze outers are off the shelf 5 mm. Garrard was 4.91 mm which was their own size. We suspect it was 5mm lapped. The outers were made by the company that made the London Taxi cabs.
Differentiate Synchronous and Asynchronous Motors :: Groschopp Blog
You must read this link. It has live chat and Bethany from Iowa had one with me. I promised you guys would be polite. Not sure what Bethany knows so just say hello from me.
You must read this link. It has live chat and Bethany from Iowa had one with me. I promised you guys would be polite. Not sure what Bethany knows so just say hello from me.
I have good verniers and can measure a papst motor made for the 124 which has the same nominal diameter, unfortunately I don't have my spare stash of E50s any longer and the two I have are currently in tables.
Papst:
0.185 inches in diameter
4.699 mm in diameter
Measurement should be considered as approximate since it was performed with an uncalibrated Mitutoyo vernier caliper, by a guy who took GDT a long, long time ago.
Given that the same pulley is used on both motors I would expect the differences to be extremely small.