"back in the day" Plumbers putty on the chassis, Mission mat, and I ran a Grace arm. I then threaded the spindle for a screw on clamp. It sat in a sealed box on a suspended platform. About the time CD's came out I was working on a thin-film headshell gain block on a ceramic substrate. Never finished.
Hi Steve,
I enjoyed both turntables and honestly speaking the SME 20 really only left because I have such limited storage space. Even within the limitations of my flawed experiment the differences are not huge and could be largely attributed to the usual PRAT related comments one hears incessantly about the TD-124, slightly better imaging, and what seemed like a little more air which while a very pleasant and often sought after artifact, might actually be a sign of an added coloration.. At best it probably says that an SME 3009 does not allow an SME 20 to shine..
My arms are all 3009 Series II, the ones with detachable shells and seem to be a reasonable match with the Zu/Denon DL-103..
I suspect that the 3009 is probably somewhat forgiving of vibration in the chassis as the knife edge presents a relatively limited area for coupling between the arm tube and the yoke. This is also probably its great weakness as that same loose coupling probably prevents the arm from properly sinking tracing induced vibration in the arm tube. The SME 20 has orders of magnitude less mechanical noise and vibration than the TD-124 and this is where the virtues of an arm tightly coupled to the upper deck of the SME 20 chassis I think would be apparent - something the 3009 was probably not designed to do.
Your comments on the TD-124 upper platter mirror my experience, I too noted that it seemed rather dead with the stock plastic mat installed, and seemed only moderately resonant without. (Others believe differently which is what I was commenting about.) I am using the Geltec dots on the platter, and IMHO this is one place where I don't question my decision to use Geltec.. I think they provide a fair amount of isolation between the main and top platters. The Zamac platter is rather ringy, although in comparison with the older TD-121 platter there were clearly some changes intended to improve the platter and perhaps control those resonances. (It didn't work) I'll post a picture of the undersides of both platters later today which will show those differences. I am not sure whether these differences along with the raised area on the top of casting on the TD-121 platter mean that these are actually two different platters or that mine is just an improved version of the earlier zamac platter - I'd have to see one from a pre 1961 MKI to know that..
This is definitely not the turntable for the obsessive compulsive person as its quirks seem to beg for constant remediation..
I had mine partially apart again last night as the mechanical noise levels had once again risen to intolerable levels - this time I was able to hear the drive train from more than 6 feet away - admittedly the noise levels in my room are rather low.
I first pulled the MKI parts unit apart to see how the bushings and thrust plate are installed in the intermediate pulley set up, and discovered that there are two bronze bushings pressed into the machined boss where the thrust plate and height adjustment are installed. (More or less what I expected) I decided it might be worthwhile to raise the pulley by 0.010" or so, and also inspected the thrust plate for condition. It had no discernible wear at all. I also gave up on the idea of oil as a lubricant as I noted both my turntables had wet lock nuts and screws.. I packed the thing with Teflon grease (I'm pretty desperate ) having noted that the bearings were as perfectly tight as I remembered.
I then reinstalled the original MKII intermediate pulley with the MKI idler, put it all back together and dusted the belt for good measure. For all of this effort I was greeted with the quietest performance I have yet experienced, but I am now skeptical - I expect it to last just a couple of days and I'll probably be doing something else next week.. I now suspect that the rack that it lives in is conspiring to make the noise seem worse than it is.. (Hard and reflective)
And finally I have lowered the chassis and leveled it with a spacing of about ~0.1" between the chassis and plinth, and may put some acousta-stuff under the plinth to try and absorb some noise from the drive train.
I should point out that because I am currently at home most of the time the TD-124 is getting about 50hrs a week of hard use and perhaps after 40yrs of disuse I really should expect some issues. And I suspect I have made more than a few mistakes along the way wrt to parts choices. I now think for the most part more traditional style replacement parts would be lower risk. In that vein I've asked for a set of Schopper motor mounting bushings for Christmas, and then I will know where there is any basis for my suspicions.
I want to talk a little bit about the bushings between the chassis and plinth as these seem to be an issue no matter whose you get. I have the geltec bushings and last night I removed the washers provided by the seller because their ID is too small to allow the bushing to seat in the height adjuster cup. Without them the bushings cause binding and make height adjustment a real chore. I'll be heading over to the local hardware store later this morning to address this issue. The other option sold on eBay also has the same issue and the original metal inserts don't seem to fit any of these bushings. When I get the slate plinth I will probably remove them, but will need to evaluate it both ways.
Maybe I am just being too obsessive about all of this...
A nice SME 10 would definitely put an end to all of this need for tinkering. Reminds me of antique British sports cars, or Russian motorcycles..
I enjoyed both turntables and honestly speaking the SME 20 really only left because I have such limited storage space. Even within the limitations of my flawed experiment the differences are not huge and could be largely attributed to the usual PRAT related comments one hears incessantly about the TD-124, slightly better imaging, and what seemed like a little more air which while a very pleasant and often sought after artifact, might actually be a sign of an added coloration.. At best it probably says that an SME 3009 does not allow an SME 20 to shine..
My arms are all 3009 Series II, the ones with detachable shells and seem to be a reasonable match with the Zu/Denon DL-103..
I suspect that the 3009 is probably somewhat forgiving of vibration in the chassis as the knife edge presents a relatively limited area for coupling between the arm tube and the yoke. This is also probably its great weakness as that same loose coupling probably prevents the arm from properly sinking tracing induced vibration in the arm tube. The SME 20 has orders of magnitude less mechanical noise and vibration than the TD-124 and this is where the virtues of an arm tightly coupled to the upper deck of the SME 20 chassis I think would be apparent - something the 3009 was probably not designed to do.
Your comments on the TD-124 upper platter mirror my experience, I too noted that it seemed rather dead with the stock plastic mat installed, and seemed only moderately resonant without. (Others believe differently which is what I was commenting about.) I am using the Geltec dots on the platter, and IMHO this is one place where I don't question my decision to use Geltec.. I think they provide a fair amount of isolation between the main and top platters. The Zamac platter is rather ringy, although in comparison with the older TD-121 platter there were clearly some changes intended to improve the platter and perhaps control those resonances. (It didn't work) I'll post a picture of the undersides of both platters later today which will show those differences. I am not sure whether these differences along with the raised area on the top of casting on the TD-121 platter mean that these are actually two different platters or that mine is just an improved version of the earlier zamac platter - I'd have to see one from a pre 1961 MKI to know that..
This is definitely not the turntable for the obsessive compulsive person as its quirks seem to beg for constant remediation..
I had mine partially apart again last night as the mechanical noise levels had once again risen to intolerable levels - this time I was able to hear the drive train from more than 6 feet away - admittedly the noise levels in my room are rather low.
I first pulled the MKI parts unit apart to see how the bushings and thrust plate are installed in the intermediate pulley set up, and discovered that there are two bronze bushings pressed into the machined boss where the thrust plate and height adjustment are installed. (More or less what I expected) I decided it might be worthwhile to raise the pulley by 0.010" or so, and also inspected the thrust plate for condition. It had no discernible wear at all. I also gave up on the idea of oil as a lubricant as I noted both my turntables had wet lock nuts and screws.. I packed the thing with Teflon grease (I'm pretty desperate
) having noted that the bearings were as perfectly tight as I remembered. I then reinstalled the original MKII intermediate pulley with the MKI idler, put it all back together and dusted the belt for good measure. For all of this effort I was greeted with the quietest performance I have yet experienced, but I am now skeptical - I expect it to last just a couple of days and I'll probably be doing something else next week..
I now suspect that the rack that it lives in is conspiring to make the noise seem worse than it is.. (Hard and reflective) And finally I have lowered the chassis and leveled it with a spacing of about ~0.1" between the chassis and plinth, and may put some acousta-stuff under the plinth to try and absorb some noise from the drive train.
I should point out that because I am currently at home most of the time the TD-124 is getting about 50hrs a week of hard use and perhaps after 40yrs of disuse I really should expect some issues. And I suspect I have made more than a few mistakes along the way wrt to parts choices. I now think for the most part more traditional style replacement parts would be lower risk. In that vein I've asked for a set of Schopper motor mounting bushings for Christmas, and then I will know where there is any basis for my suspicions.
I want to talk a little bit about the bushings between the chassis and plinth as these seem to be an issue no matter whose you get. I have the geltec bushings and last night I removed the washers provided by the seller because their ID is too small to allow the bushing to seat in the height adjuster cup. Without them the bushings cause binding and make height adjustment a real chore. I'll be heading over to the local hardware store later this morning to address this issue. The other option sold on eBay also has the same issue and the original metal inserts don't seem to fit any of these bushings. When I get the slate plinth I will probably remove them, but will need to evaluate it both ways.
Maybe I am just being too obsessive about all of this...
A nice SME 10 would definitely put an end to all of this need for tinkering. Reminds me of antique British sports cars, or Russian motorcycles..
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I assume that table has long since moved on or do you still have it? Sounds like you put a lot of thought and effort into your set up..
Changed my mind on the washer thing, realized that I probably won't need to adjust them again anytime soon, and it is a very balmy and breezy -7 C (19 F) out there right now.. No need to walk to the hardware store in that for something I don't really need anyway..
Edit: It still runs quietest with the original belt, with the CB965 being significantly better than when new, but still slightly noisier than the original belt.
Edit: It still runs quietest with the original belt, with the CB965 being significantly better than when new, but still slightly noisier than the original belt.
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Belt and Noise Update
In my previous post I stated that the original belt ran quieter than the Thakker sourced CB965. This comparison was done prior to the tweaks performed yesterday and I decided since I have so much free time on my hands and I was curious that I would rerun the test..
The results were different today, perhaps fresher ears or more likely the situation has changed. I would now be hard pressed to tell any difference between the Thakker sourced CB965 and the original belt. Both seem to be equally quiet which I think removes one variable from the equation long term. Both were freshly talc'd in order that the comparison be performed in such a way as to give both belts the greatest advantage as the talc application does result in a quieter running belt.
My conclusion is that with a couple of hundred hours of use the current CB965 will perform comparably to an original at least if talc is applied periodically. To those wondering about the 12.1" recommended belt length they stretch... a lot.. Mine is now over 12.8" in length.
For those who want a looser belt and live in a 60Hz region perhaps turning the motor pulley over and running it overnight with idler pulley and platter off will elongate the belt sufficiently..
FWIW I am coming to the conclusion that I am never going to get the drive train in this particular table to be quiet enough to make me entirely happy. I've heard what seemed like quieter tables, but they were all MKI in a very large open space with an unknown ambient noise level - so I don't know whether or not they were really quieter. It seems that they just make a little bit of noise, and it is more than I am used to or comfortable with. The motors in these turntables vibrate a lot as you would imagine given that they are only 4 poles and run quite fast (~1800rpm) I am not sure that ultimately there is anything beyond good bearing alignment, good mounts, and a soft pliant belt to keep it out of the platter. I suspect the motor is now the dominant noise source, bearing alignment is good.. As I indicated I will probably replace those bearings with some I think might be better. (Analog Depot bearings) Note that this should not be construed that I am going to stop using or listening to my table, but perhaps I will have to learn to ignore that particular "mechanical symphony."
It still sounds great IMHO, and I think a careful noise analysis with spectrum analyzer and blank track with probably demonstrate that the table is quieter than the source material it is playing - and in the end this is really what matters. Thanks to Pano I now have a test disk, and when I feel motivated I may back this conjecture with some measurements.
I would though very strongly recommend staying away from the tweaks on eBay and buying as close replacements in spirit to the original parts as possible until you are sure everything is right, and then introduce the tweaks you are interested in one at a time so that you can access whether or not they represent an upgrade or not.. I will be/am doing a lot of things over again in an effort to answer that question.
In my previous post I stated that the original belt ran quieter than the Thakker sourced CB965. This comparison was done prior to the tweaks performed yesterday and I decided since I have so much free time on my hands and I was curious that I would rerun the test..
The results were different today, perhaps fresher ears or more likely the situation has changed. I would now be hard pressed to tell any difference between the Thakker sourced CB965 and the original belt. Both seem to be equally quiet which I think removes one variable from the equation long term. Both were freshly talc'd in order that the comparison be performed in such a way as to give both belts the greatest advantage as the talc application does result in a quieter running belt.
My conclusion is that with a couple of hundred hours of use the current CB965 will perform comparably to an original at least if talc is applied periodically. To those wondering about the 12.1" recommended belt length they stretch... a lot.. Mine is now over 12.8" in length.
For those who want a looser belt and live in a 60Hz region perhaps turning the motor pulley over and running it overnight with idler pulley and platter off will elongate the belt sufficiently..
FWIW I am coming to the conclusion that I am never going to get the drive train in this particular table to be quiet enough to make me entirely happy. I've heard what seemed like quieter tables, but they were all MKI in a very large open space with an unknown ambient noise level - so I don't know whether or not they were really quieter. It seems that they just make a little bit of noise, and it is more than I am used to or comfortable with. The motors in these turntables vibrate a lot as you would imagine given that they are only 4 poles and run quite fast (~1800rpm) I am not sure that ultimately there is anything beyond good bearing alignment, good mounts, and a soft pliant belt to keep it out of the platter. I suspect the motor is now the dominant noise source, bearing alignment is good.. As I indicated I will probably replace those bearings with some I think might be better. (Analog Depot bearings) Note that this should not be construed that I am going to stop using or listening to my table, but perhaps I will have to learn to ignore that particular "mechanical symphony."
It still sounds great IMHO, and I think a careful noise analysis with spectrum analyzer and blank track with probably demonstrate that the table is quieter than the source material it is playing - and in the end this is really what matters. Thanks to Pano I now have a test disk, and when I feel motivated I may back this conjecture with some measurements.
I would though very strongly recommend staying away from the tweaks on eBay and buying as close replacements in spirit to the original parts as possible until you are sure everything is right, and then introduce the tweaks you are interested in one at a time so that you can access whether or not they represent an upgrade or not.. I will be/am doing a lot of things over again in an effort to answer that question.
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@ Steve,
I've noticed since the overhaul that once warm the table runs on speed only at the extreme (-3%) end of the speed adjustment range. Apparently I have been quite good at reducing drag... Even with the brake magnet adjusted about as close to the intermediate pulley as I can get it there is no real adjustment range left. I'm going to try the next voltage tap up, noting that I have seen one other table set this way presumably due to the same issue.. My line voltage is at the upper end of the lowest setting range.. Not sure if this will help or not, but have made the change over and will see what if any effect it has on the that particular issue.
Comment post change:
Changing the tap improved the situation considerably, and in fact I have just backed the brake magnet off very slightly to allow more adjustment range at the top of the speed range as it was not quite centered. (Motor is warm..) Will test that now..
Have just checked after the quick brake adjustment and the speed range seems well centered. Seems that this should result in a cooler running motor and more or less a reasonably centered speed adjustment range.
My line voltage is never lower than 117 and rarely higher than 121V as a point of reference.. (The waveform unfortunately is a clipped sine..)
Has no discernible effect on drive train noise levels..
I've noticed since the overhaul that once warm the table runs on speed only at the extreme (-3%) end of the speed adjustment range. Apparently I have been quite good at reducing drag...
Even with the brake magnet adjusted about as close to the intermediate pulley as I can get it there is no real adjustment range left. I'm going to try the next voltage tap up, noting that I have seen one other table set this way presumably due to the same issue.. My line voltage is at the upper end of the lowest setting range.. Not sure if this will help or not, but have made the change over and will see what if any effect it has on the that particular issue.Comment post change:
Changing the tap improved the situation considerably, and in fact I have just backed the brake magnet off very slightly to allow more adjustment range at the top of the speed range as it was not quite centered. (Motor is warm..) Will test that now..
Have just checked after the quick brake adjustment and the speed range seems well centered. Seems that this should result in a cooler running motor and more or less a reasonably centered speed adjustment range.
My line voltage is never lower than 117 and rarely higher than 121V as a point of reference.. (The waveform unfortunately is a clipped sine..)
Has no discernible effect on drive train noise levels..
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re: speed pitch control.
experience relative to early mk1 production models with iron platter.
I have stable speed with the pitch adjuster left relatively in the center of its adjustment range. Been like that for the past couple of years. Actually, the TT itself (#2729) has been rock solid and issue free for that period. I experience no compulsive need to futz about with it. -- But then this relaxed attitude is a result of a protracted initial period, with #2729, when I, in fact, did obsessively futz about with it.
Early on (first project) when I did have speed pitch issues I found that the remedies were to do with reduction of excess drag at all bushing/shaft interfaces. Which includes motor/idler wheel/step pulley/platter brg. No special mods necessary. Just standard common sense maintenance. (aka clean and lube)
re: step pulley lube.
likely the step pulley axle bushings are of the sintered bronze type (lube retaining oilite). Using grease here would clog up the pores of an Oilite bushing. Which defeats the intended purpose of using Oilite bushings in the first place. On the other hand, the grease, if low enough viscosity, will likely lubricate fairly well. And if the use of grease * seems to lower your pulley noise, then that may point toward the problem area. (a little bit too much bearing/shaft working clearance)
(* Assuming the grease to be of much higher viscosity than 20 wt oil)
Mk 1 step pulley bearing design precludes the option of filling a bearing housing up with lube to act as a reservoir. Rather, a light smear of 20 wt on the shaft prior to fitment is all that is needed.
Under normal conditions I see no wisdom in using any type of grease at this bushing/shaft interface. However if it is indeed established that there is an excess amount of running clearance between shaft and bushing, then the use of a heavier lube (aka grease) may be warranted as a stop gap measure.
I have been using the 110-120 voltage tap on my mk1 refurbishes with never any need to experiment. VAC in my room is typically 117 - 120. Your observation of a clipped sine wave (oscilloscope) does point to the potential for having a dedicated power supply of the sine wave generator type. At this juncture, even Loricraft offers one for their Garrard 301/401 customers. And the 301/401 does use a similar breed of motor. (shaded pole induction) The Loricraft PS is too pricey though. One needs to offer one at a much lower price, low enough to put one on every TD124 out there.
-Steve
experience relative to early mk1 production models with iron platter.
I have stable speed with the pitch adjuster left relatively in the center of its adjustment range. Been like that for the past couple of years. Actually, the TT itself (#2729) has been rock solid and issue free for that period. I experience no compulsive need to futz about with it. -- But then this relaxed attitude is a result of a protracted initial period, with #2729, when I, in fact, did obsessively futz about with it.
Early on (first project) when I did have speed pitch issues I found that the remedies were to do with reduction of excess drag at all bushing/shaft interfaces. Which includes motor/idler wheel/step pulley/platter brg. No special mods necessary. Just standard common sense maintenance. (aka clean and lube)
re: step pulley lube.
likely the step pulley axle bushings are of the sintered bronze type (lube retaining oilite). Using grease here would clog up the pores of an Oilite bushing. Which defeats the intended purpose of using Oilite bushings in the first place. On the other hand, the grease, if low enough viscosity, will likely lubricate fairly well. And if the use of grease * seems to lower your pulley noise, then that may point toward the problem area. (a little bit too much bearing/shaft working clearance)
(* Assuming the grease to be of much higher viscosity than 20 wt oil)
Mk 1 step pulley bearing design precludes the option of filling a bearing housing up with lube to act as a reservoir. Rather, a light smear of 20 wt on the shaft prior to fitment is all that is needed.
Under normal conditions I see no wisdom in using any type of grease at this bushing/shaft interface. However if it is indeed established that there is an excess amount of running clearance between shaft and bushing, then the use of a heavier lube (aka grease) may be warranted as a stop gap measure.
I have been using the 110-120 voltage tap on my mk1 refurbishes with never any need to experiment. VAC in my room is typically 117 - 120. Your observation of a clipped sine wave (oscilloscope) does point to the potential for having a dedicated power supply of the sine wave generator type. At this juncture, even Loricraft offers one for their Garrard 301/401 customers. And the 301/401 does use a similar breed of motor. (shaded pole induction) The Loricraft PS is too pricey though. One needs to offer one at a much lower price, low enough to put one on every TD124 out there.
-Steve
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Hi Steve,
Thanks for the quick response.. My problem is that the turntable actually runs just a bit fast after all of the work I have done. (Adjusted to the low end of the speed range it ran on speed.) The viscosity of the lubricants I've used was close to the originals.. (20 wt)
My suspicion about the intermediate bearings given the condition of the motor bearings before replacement is that they are already clogged with congealed lubricant which could well be the problem I'm addressing with the grease. It is a fairly low viscosity grease, but it's grease. And yes they are oilite bearings..
I could do some limited disassembly and carefully run some solvent through the intermediate pulley bearing housing..
Changing the voltage setting reduced the torque by somewhat more than 3% based on the current brake magnet position and the setting of the speed control..
Thanks for the quick response.. My problem is that the turntable actually runs just a bit fast after all of the work I have done. (Adjusted to the low end of the speed range it ran on speed.) The viscosity of the lubricants I've used was close to the originals.. (20 wt)
My suspicion about the intermediate bearings given the condition of the motor bearings before replacement is that they are already clogged with congealed lubricant which could well be the problem I'm addressing with the grease. It is a fairly low viscosity grease, but it's grease. And yes they are oilite bearings..
I could do some limited disassembly and carefully run some solvent through the intermediate pulley bearing housing..
Changing the voltage setting reduced the torque by somewhat more than 3% based on the current brake magnet position and the setting of the speed control..
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Use of Grease
If you look on the Schopper website, they sell an idler wheel silencing kit that consists of some washers and bushing and some grease. They claim that the grease was originally used by Thorens. I am wondering if the grease is used on the thrust surfaces only and the oil used for the idler wheel bearing. Any ideas?
Grease may actually be the correct lubricant to use on the bearings of noisy components, such as the intermediate shaft. Is it possible the bearings on the intermediate shaft are just solid bronze and not sintered and oil impregnated, as is the case with the motor bearings?
If you look on the Schopper website, they sell an idler wheel silencing kit that consists of some washers and bushing and some grease. They claim that the grease was originally used by Thorens. I am wondering if the grease is used on the thrust surfaces only and the oil used for the idler wheel bearing. Any ideas?
Grease may actually be the correct lubricant to use on the bearings of noisy components, such as the intermediate shaft. Is it possible the bearings on the intermediate shaft are just solid bronze and not sintered and oil impregnated, as is the case with the motor bearings?
I've seen that kit.
An externally hosted image should be here but it was not working when we last tested it.
Reading through their text it suggests this kit as a means to restore original performance. Reading between the lines I think it suggests that you can compensate for worn idler wheel bushings by increasing the viscosity of the lubrication at that point.
Further notes on Schopper and idler wheels. Schopper is one of those who suggests that original idler wheels, when in undamaged (no flat spots at tire perifery) condition, should be re-used.
At some point I predict they will reverse their position on the idler wheel issue and begin offering new replacements at exhorbitant prices. When that happens wait for them to extoll the virtue of having new idler bearings to correct running clearances between bushing and shaft and also they will extoll the virtues of fresh, optimally compliant, tire rubber.
Fwiw, the service manual does not suggest using grease anywhere on this player.
However, I'm sure it won't hurt to use a little grease in areas of obvious high wear. And that should improve the performance of worn idler wheel bushings.
-Steve
Schopper Grease
That is the kit that I saw. I have never seen grease on idlers with bronze bushings, and as you say, it is not in the Thorens manuals. New idler wheels are probably a good idea, irrespective of what is suggested today. Doubtless that at some point, they will market a new idler and the price will not be easy to swallow, for sure.
What idler replacement do you recommend? Also, when will your motor bushing kits be available again? Inquiring minds want to know!
That is the kit that I saw. I have never seen grease on idlers with bronze bushings, and as you say, it is not in the Thorens manuals. New idler wheels are probably a good idea, irrespective of what is suggested today. Doubtless that at some point, they will market a new idler and the price will not be easy to swallow, for sure.
What idler replacement do you recommend? Also, when will your motor bushing kits be available again? Inquiring minds want to know!
I'm with Steve on the grease vs oil issue.. Thorens recommends a very specific oil which it turns out is similar to a fine grade of 20wt sae electric motor oil or the similar zoom spout turbine oil..
I also determined pretty quickly that while a convenient fix for the pitch control issues moving the voltage selector to the 125 - 150V just introduces a new set of issues. I ended up going back to the original 100 - 120V setting almost immediately - I'm glad I satisfied my curiosity. The issues I noted is that it takes substantially longer for the turntable to start and come up to something like playing speed. When it is cold it runs very slow, and takes much longer to get to full operating speed. This change when warm and running on speed also seems to significantly compromise the sense of energy and timing to the music. It sounds for lack of a better word a bit weak..
I cleaned out the intermediate bearing housing with an alcohol based solvent and then fill the housing with oil and after a few minutes wicked it out and replaced it and allowed it to soak for a half hour before reinserting a now very polished intermediate pulley. No increase in noise levels and in fact the intermediate pulley is now running fairly quietly.
Motor cogging does seem to have increased, and I need to investigate why or perhaps the other noises now all eliminated were masking it. I have another complete drive train I am going to resurrect for comparative purposes. I want to make sure I don't have some other as yet misunderstood issue. I am very, very, very suspicious of those motor bearings, but probably without good cause.
It continues to beguile me with its sound which is why I am trying so hard I guess, and it is obviously improving. All of this work does seem to have an audible payoff, but one heck of a steep learning curve. I'm starting to wonder how many amateur restorations really have brought the table back performance wise to where it was when new. I believe Steve's are there, mine certainly isn't to the best of my ability to tell, but has come a long way.. This table is a lot more complex than it appears on the surface and with no frame of reference and vague Thorens comments to the effect that no table is silent makes it harder to know when you have arrived at the limits of the table's performance envelope..
I also determined pretty quickly that while a convenient fix for the pitch control issues moving the voltage selector to the 125 - 150V just introduces a new set of issues. I ended up going back to the original 100 - 120V setting almost immediately - I'm glad I satisfied my curiosity. The issues I noted is that it takes substantially longer for the turntable to start and come up to something like playing speed. When it is cold it runs very slow, and takes much longer to get to full operating speed. This change when warm and running on speed also seems to significantly compromise the sense of energy and timing to the music. It sounds for lack of a better word a bit weak..
I cleaned out the intermediate bearing housing with an alcohol based solvent and then fill the housing with oil and after a few minutes wicked it out and replaced it and allowed it to soak for a half hour before reinserting a now very polished intermediate pulley. No increase in noise levels and in fact the intermediate pulley is now running fairly quietly.
Motor cogging does seem to have increased, and I need to investigate why or perhaps the other noises now all eliminated were masking it. I have another complete drive train I am going to resurrect for comparative purposes. I want to make sure I don't have some other as yet misunderstood issue. I am very, very, very suspicious of those motor bearings, but probably without good cause.
It continues to beguile me with its sound which is why I am trying so hard I guess, and it is obviously improving. All of this work does seem to have an audible payoff, but one heck of a steep learning curve. I'm starting to wonder how many amateur restorations really have brought the table back performance wise to where it was when new. I believe Steve's are there, mine certainly isn't to the best of my ability to tell, but has come a long way.. This table is a lot more complex than it appears on the surface and with no frame of reference and vague Thorens comments to the effect that no table is silent makes it harder to know when you have arrived at the limits of the table's performance envelope..
Yes, running fast. Indicates the 'lack of drag' somewhere? Or is it something else? Not sure. Puzzled. Whenever things don't make sense I try to focus back on the basic truths of a thing.
Here's some info I have on shaded pole motors:
If drive voltage can change motor rpm by as much as 5%, that indicates that voltage level isn't a huge factor in how fast or slow one of these motors runs. Although one presumes there needs to be a minimum voltage to operate at all. Although I recall testing a motor out of chassis with a adjustable output power supply and was able to observe the motor spinning (slowly) on 25 vac.
10% torque load. Presumably this is where the eddy brake (magnet alignment) comes into play. But adjustment of the eddy brake magnet for alignment isn't critical unless it is way off to begin with. Another thought regarding torque load. Altering the voltage input at the motor has the effect of change to the motor's torque output. If higher voltage results in lower torque, and 10% of the motor's speed is in relation to torque load, that could account for a reduction in speed of the drive train when changing to a higher voltage setting at the commutator.
85% mains frequency. If we know we've got 60 hz, then...
So it suggests a mechanical fault somewhere. One thing that pops into mind; belt thickness. When calculating driven pulley speeds in rpm one has to add 1/2 the belt thickness to the diameter of the pulleys. When Thorens made these players you know they did this and that there will be a belt thickness that these players are designed to use. so, in theory, if one uses too thick of a belt it would have the virtual effect of increasing pulley diameter, and thus cause a fast speed at the driven pulley.
So to prove that out, one would change to a thinner cross section belt to observe if there was any speed reduction.
re: step pulley bushings. At this point you can soak the bushings in solvent any time you choose. It should not matter if you've added some fresh grease. That will wash out as well as any gummed up lube left there from 40 years past. Probably it should be done as a matter of course in the beginnings.
just brainstorming.
-Steve
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The only one I know of currently available and that Steve has used with good success is the one offered by Mirko sq38s on eBay. It's $75 and the current ones have oilite bronze bearings according to the listing.
Here: Idler Wheel for Thorens TD-124 Turntable - New!!! - eBay (item 350414627421 end time Dec-17-10 00:08:56 PST)
My current idler which was salvaged off of my MKI parts unit is in excellent condition, however two of the four idler pulleys I have seen so far close up and personal had issues that probably make it beneficial to replace with a new one.
I am sure Schopper is recommending retaining the original idler when one in truly excellent condition is on the table, but a significant number probably have deteriorated to the point where replacing them makes sense.
As far as I know Steve's motor bearings are currently available, and installed two sets a little over a week ago, and those were shipped to the work site overnight less than two weeks ago. I am confident recommending these based on my experience installing two pairs.
Brainstorming more than OK IMO..
Problem exists with both intermediate pulleys, one I've polished, and one I have not touched at all.
It could well be the belt thickness as it is substantially greater than the original belt that came with the table. I also have a thinner after market belt as well that I can try.. Note that the belt currently on the table is a genuine Thorens CB965 replacement belt purchased from Thakker, and it is almost 50% thicker than the belt originally on the table.. (Note that early on it did seem to run at the correct speed with either belt.)
A small reduction in drag is possible due to the installation of a different main bearing end cap/thrust plate, but I would expect this to be a tiny difference. It's not like this platter spins for endless ages like some TD-124 owners brag about. It's done in roughly 45 seconds from 33 rpm, and hasn't changed appreciably as a result of the end cap upgrade.
So that brings us back to the belt or lubricants that are too low in viscosity.
I cleaned out the intermediate pulley bearings and it seems to run unobtrusively now.
Puzzling, and in fact now when fully warmed up it runs just very slightly fast since i removed the grease from the intermediate pulley bearings. Edit: I was able to tweak the eddy current brake a little and I now have a little range left over after adjusting to run on speed warm..
Just another mystery to solve..
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Some pictures, power quality, ramblings..
Thought I would share some more pictures showing my fitful progress..
Today the table is running extremely quietly. Quite a contrast from last night, and I have unfortunately spent little time listening today because I have been very busy with job hunt related stuff.
The intermediate pulley is making little if any noise, there is some slight idler pulley singing on the platter, but very muted, and there is some motor noise - much less than last night which makes me suspect power quality which I know to be a problem outside of strictly line voltage.
The AC waveform here at times looks like what you would expect from a close to saturated pole pig.. Sort of a trapezoid with variable slopes, so some sort of power regeneration is probably advisable. I designed the rest of my electronics to be as immune as possible to these issues as I know how..
I have posted a picture of the turntable with the platter off, I think people may be surprised at how clean it is. As I indicated previously this is an extremely low hour unit that was "stored" in heated and conditioned space its entire life. You can see the results of my work and cleaning quite clearly in the pictures.
I spent some time over-zealously polishing the intermediate pulley with scotch-brite, this was probably a bit excessive and if you look carefully at the picture I posted you may see that. I did clean it before reinstalling it, but not before the picture. This in conjunction with the stretched and talc'd CB965 has finally resulted in a relatively quiet running intermediate pulley. I will probably spend some time with an emery cloth and polish it further, anything that reduces belt chatter.. The motor obviously cogs and I don't believe there is anything I can do about that as I mentioned in a previous post, but it is well isolated, and not transmitted to the chassis or platter.. What more could one ask for? Audibly quieter running overall would be nice, but I don't think I'm going to get there. The motor runs dead silent under no load, and when loaded makes some noise.. Bearing alignment is good, no further reduction in noise results from tweaking the bearing alignment.
Not sure ultimately what the solution to the pitch control range issue will be. Possibly a different belt, and/or slightly higher viscosity oil in the main bearing. My overhaul has probably reduced overall mechanical drag to levels significantly lower than the table originally had. It runs on speed, but the adjustment range is scewed towards the run fast end of the range and this is with the brake configured to provide the maximum braking force of which it is capable. There are no pitch stability issues at all. I'm going to do some research and see what I can come up with.
Finally as promised I have posted a picture that clearly shows the difference between a zamac platter installed on the much earlier TD-121 and one installed on my very late TD-124. Note the small spindle - never thought a 10mm spindle would look puny, but next to that 14mm monster it is puny and then some. While not obvious the pitch of the bolt pattern is identical and these platters can be interchanged with just the swap of the spindle assemblies. The casting on my late TD-124 has clearly evolved and there are a number of differences between them. I am not sure whether the raised center of the TD-121 platter would interfere with the clutch mechanism and upper platter on a TD-124, but I'm not really curious enough to try this.. I have some thoughts of damping the inside of the platter where clearances permit.. Note that the late zamac platter has only a strobe pattern for 33 1/3 rpm at 50 and 60Hz.. I have seen erroneous references on line to 16 2/3 as well as 33 1/3 rpm strobe patterns on these platters, which is certainly not the case with the few I have seen.
Thought I would share some more pictures showing my fitful progress..
Today the table is running extremely quietly. Quite a contrast from last night, and I have unfortunately spent little time listening today because I have been very busy with job hunt related stuff.
The intermediate pulley is making little if any noise, there is some slight idler pulley singing on the platter, but very muted, and there is some motor noise - much less than last night which makes me suspect power quality which I know to be a problem outside of strictly line voltage.
The AC waveform here at times looks like what you would expect from a close to saturated pole pig..
Sort of a trapezoid with variable slopes, so some sort of power regeneration is probably advisable. I designed the rest of my electronics to be as immune as possible to these issues as I know how..I have posted a picture of the turntable with the platter off, I think people may be surprised at how clean it is. As I indicated previously this is an extremely low hour unit that was "stored" in heated and conditioned space its entire life. You can see the results of my work and cleaning quite clearly in the pictures.
I spent some time over-zealously polishing the intermediate pulley with scotch-brite, this was probably a bit excessive and if you look carefully at the picture I posted you may see that. I did clean it before reinstalling it, but not before the picture. This in conjunction with the stretched and talc'd CB965 has finally resulted in a relatively quiet running intermediate pulley. I will probably spend some time with an emery cloth and polish it further, anything that reduces belt chatter.. The motor obviously cogs and I don't believe there is anything I can do about that as I mentioned in a previous post, but it is well isolated, and not transmitted to the chassis or platter.. What more could one ask for? Audibly quieter running overall would be nice, but I don't think I'm going to get there. The motor runs dead silent under no load, and when loaded makes some noise.. Bearing alignment is good, no further reduction in noise results from tweaking the bearing alignment.
Not sure ultimately what the solution to the pitch control range issue will be. Possibly a different belt, and/or slightly higher viscosity oil in the main bearing. My overhaul has probably reduced overall mechanical drag to levels significantly lower than the table originally had. It runs on speed, but the adjustment range is scewed towards the run fast end of the range and this is with the brake configured to provide the maximum braking force of which it is capable. There are no pitch stability issues at all. I'm going to do some research and see what I can come up with.
Finally as promised I have posted a picture that clearly shows the difference between a zamac platter installed on the much earlier TD-121 and one installed on my very late TD-124. Note the small spindle - never thought a 10mm spindle would look puny, but next to that 14mm monster it is puny and then some. While not obvious the pitch of the bolt pattern is identical and these platters can be interchanged with just the swap of the spindle assemblies. The casting on my late TD-124 has clearly evolved and there are a number of differences between them. I am not sure whether the raised center of the TD-121 platter would interfere with the clutch mechanism and upper platter on a TD-124, but I'm not really curious enough to try this.. I have some thoughts of damping the inside of the platter where clearances permit.. Note that the late zamac platter has only a strobe pattern for 33 1/3 rpm at 50 and 60Hz.. I have seen erroneous references on line to 16 2/3 as well as 33 1/3 rpm strobe patterns on these platters, which is certainly not the case with the few I have seen.
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Merrill-Scillia E.D.M Mat, Sound, Noise..
The MSR EDM mat arrived this afternoon just as I was about to sit down to eat some lunch.. Naturally lunch was delayed while I unpacked and installed the mat.
This is a lead/composite (looks a bit like cork) mat and was modified by Merrill for use on the TD-124.. Weighs almost 1 1/2lbs which in conjunction with the record weight means I have added almost 2 1/2 lbs of mass to the platter, however given the fact that the cast platter weighs several more lbs than the zamac platter I am not concerned about the additional weight. It does make operating the clutch a little trickier due to the added weight on the upper platter.. I expect the dots will need more frequent replacement as well, and I leave it sitting on the clutch when shut off when I can remember to do so..
So you're probably wondering what it did to the sound... Given I have been listening only for a few hours my observations aren't comprehensive.
The "zing" I have mentioned in previous posts is completely absent as is most of the air that I really enjoyed - obviously an artifact of the mat itself.
The sound is tighter, and a bit more controlled. It might be just a little over damped for my tastes. Drier... It sounds more technically correct, and a bit less lively. Oddly this reminds me a lot of the SME 20 sound in fact. (Within the realms of faulty auditory memory, and bearing in mind my comments about fair comparisons to the SME.)
There is clearly more low level and HF detail evident, and the noise floor, never high to begin with seems subjectively even lower.
Imaging seems to have gained some additional precision, depth seems largely unchanged and is still a major improvement compared to turntables past.
Some particularly well recorded material does sound noticeably more natural, and warmer, more fluid.
Percussive sounds retain their impact, no softening apparent..
Overall this is a better compromise than the other mats I have tried, but it does alter the sound of this table, whether that is a radical change or not I have not quite figured it out.
After the initial shock, (it does sound different) and listening to a slowly widening range of material I feel that this a very significant overall improvement.
The additional mass seems to have solved my pitch control issues, as the loading on the main bearing is rather significantly increased. (Probably getting to be time for a silicon nitride ball bearing on the spindle..)
The table has remained relatively quiet as compared to a few days back.. I think I might be getting to the end of needing "desperate" tweaks. Power quality is an issue here, and I think I am going to look at a clean 60Hz sine source to power this table down the road.
Next big change hopefully will be a slate plinth.. Then maybe a better platter..
The MSR EDM mat arrived this afternoon just as I was about to sit down to eat some lunch.. Naturally lunch was delayed while I unpacked and installed the mat.
This is a lead/composite (looks a bit like cork) mat and was modified by Merrill for use on the TD-124.. Weighs almost 1 1/2lbs which in conjunction with the record weight means I have added almost 2 1/2 lbs of mass to the platter, however given the fact that the cast platter weighs several more lbs than the zamac platter I am not concerned about the additional weight. It does make operating the clutch a little trickier due to the added weight on the upper platter.. I expect the dots will need more frequent replacement as well, and I leave it sitting on the clutch when shut off when I can remember to do so..
So you're probably wondering what it did to the sound... Given I have been listening only for a few hours my observations aren't comprehensive.
The "zing" I have mentioned in previous posts is completely absent as is most of the air that I really enjoyed - obviously an artifact of the mat itself.
The sound is tighter, and a bit more controlled. It might be just a little over damped for my tastes. Drier... It sounds more technically correct, and a bit less lively. Oddly this reminds me a lot of the SME 20 sound in fact. (Within the realms of faulty auditory memory, and bearing in mind my comments about fair comparisons to the SME.)
There is clearly more low level and HF detail evident, and the noise floor, never high to begin with seems subjectively even lower.
Imaging seems to have gained some additional precision, depth seems largely unchanged and is still a major improvement compared to turntables past.
Some particularly well recorded material does sound noticeably more natural, and warmer, more fluid.
Percussive sounds retain their impact, no softening apparent..
Overall this is a better compromise than the other mats I have tried, but it does alter the sound of this table, whether that is a radical change or not I have not quite figured it out.
After the initial shock, (it does sound different) and listening to a slowly widening range of material I feel that this a very significant overall improvement.
The additional mass seems to have solved my pitch control issues, as the loading on the main bearing is rather significantly increased. (Probably getting to be time for a silicon nitride ball bearing on the spindle..)
The table has remained relatively quiet as compared to a few days back.. I think I might be getting to the end of needing "desperate" tweaks. Power quality is an issue here, and I think I am going to look at a clean 60Hz sine source to power this table down the road.
Next big change hopefully will be a slate plinth.. Then maybe a better platter..
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