I think viscosity probably plays the biggest role here, but would certainly recommend something sans detergent for bearing lubrication.
I think the eddy current brake in this design is a pretty big liability. I am starting to think about ways to eliminate it in at least one of my two tables. No matter what I do there is always noise from the brake, worse reducing voltage to the motor which reduces the torque easing demands on the brake just seems to sap the table of its dynamics, but I have no idea why.
I will soon have a Papst Aussenlaufer motor to experiment with and plan to try 3 phase power with it using a yet to be procured/modified variable frequency drive. Measurements performed by Volken on another related thread indicate that this motor on single phase power is about as noisy as the original E50. Others have remarked on the lack of torque. 3 phase power in theory should address both of these concerns.
I think the eddy current brake in this design is a pretty big liability. I am starting to think about ways to eliminate it in at least one of my two tables. No matter what I do there is always noise from the brake, worse reducing voltage to the motor which reduces the torque easing demands on the brake just seems to sap the table of its dynamics, but I have no idea why.
I will soon have a Papst Aussenlaufer motor to experiment with and plan to try 3 phase power with it using a yet to be procured/modified variable frequency drive. Measurements performed by Volken on another related thread indicate that this motor on single phase power is about as noisy as the original E50. Others have remarked on the lack of torque. 3 phase power in theory should address both of these concerns.
I beat some one out there would think its the only way to fly, lol. It would surely take up some realestate, lol.
if you wanted to get fancy you could sensor the table speed and use a pic to run the table through the vfd. We did similar whit some very cheap and simple plc's running high tech pumps for hydrogen electrolytes. Well simple if your good at writing code that is. I'm not.
Keep em turnin to the right.
if you wanted to get fancy you could sensor the table speed and use a pic to run the table through the vfd. We did similar whit some very cheap and simple plc's running high tech pumps for hydrogen electrolytes. Well simple if your good at writing code that is. I'm not.
Keep em turnin to the right.
The TD-124 in all incarnations is quite common here, I own two in running order, and one parts unit. I have a number of friends who own at least one. The first ones were imported here in late 1957/58 time frame and I have worked on one with a serial # of just over 1000..The TD-124 was brought to market with strong encouragement from the U.S. importer - it may be the case that without it, it might not have made it to production. I am not sure of the exact numbers but I suspect roughly half of the entire production of TD-124 were sold here in the USA. .
Well, Thorens are worth gold now... Everyone I see for sale has many $$$ next to it... sigh.
I owned three 124s over the years and I sold two and one I gave it away. From what I heard at the time I thought it was junk: noisy, rumbly, no resolution. I sold the two for dirt cheap right before the Art Dudley Stereophile articles that skyrocketed their prices to be near the Garrard 301! And the last one I had to force my friend to take it away as I just couldn't stand it! Well, I wish I could've kept at least one so I could tinker it following some of the instructions online, like here, to improve it. Too late now as I'm priced out by the current market! Sigh...
I fill to just above the top of the bottom oilite bushing, this seems to avoid oil slicks on the chassis until the next time you pull the spindle. I like to run the spindle wet, and ideally right up to the upper bushing. As you know overfilling results in oil everywhere you don't want it to be.. lol
I should note that I have aftermarket endcaps on both of my tables and used RTV blue on both sides of a new paper gasket in order avoid blow outs when inserting the spindle into the oil. Some of the oil flows in the space between the spindle and bushing and some through the bushing itself.
The heavier weight oil in the bearing housing seems to improve performance even with unworn bushings. Unfortunately with high average line voltages it still does not introduce enough drag to completely quiet down the eddy current brake.
Last night I ran an experiment with my TD-124/II and found on the 100 - 120V tap that it ran quite happily at voltages below 100V, and at the value I settled on of 101V the brake was well centered in its adjustment range and also much quieter since it was not working nearly as hard. I've purchased a box and will get a 50VA toroid (overkill) from Antek and wire it to buck my line voltage - I'll make it switchable and am probably going to use a 6V dual secondary that can be configured to buck 6 or 12V.. I may add some additional turns if I want slightly higher bucking voltages, since they will only be in series any slight differences in windings should not matter. I will fuse the input at 2A for safety and ground the box through a 3 wire cord.
I should note that I have aftermarket endcaps on both of my tables and used RTV blue on both sides of a new paper gasket in order avoid blow outs when inserting the spindle into the oil. Some of the oil flows in the space between the spindle and bushing and some through the bushing itself.
The heavier weight oil in the bearing housing seems to improve performance even with unworn bushings. Unfortunately with high average line voltages it still does not introduce enough drag to completely quiet down the eddy current brake.
Last night I ran an experiment with my TD-124/II and found on the 100 - 120V tap that it ran quite happily at voltages below 100V, and at the value I settled on of 101V the brake was well centered in its adjustment range and also much quieter since it was not working nearly as hard. I've purchased a box and will get a 50VA toroid (overkill) from Antek and wire it to buck my line voltage - I'll make it switchable and am probably going to use a 6V dual secondary that can be configured to buck 6 or 12V.. I may add some additional turns if I want slightly higher bucking voltages, since they will only be in series any slight differences in windings should not matter. I will fuse the input at 2A for safety and ground the box through a 3 wire cord.
I don't quite remember when I got my first (the TD-124/II) relative to the Dudley article, but by that time I had had first right of refusal on this particular table for about 9yrs.. lol In the early years I was not too thrilled about the whole idea, and in fact when I finally went to Manhattan to pick it up I still was not entirely sold. Figured at worst I could resell it in running order for a bit more than I paid for it. So I decided to give it the best shot I could as you may have noted from this thread, and to say the least I was surprised at how good it sounded compared to just about anything I had heard up to that time. It clobbered my own TD-125 with same arm and cartridge, and while not as quiet mechanically or rumblewise as an SME-20/2 it otherwise acquitted itself rather well. Not to say there are not some problems, the induction motor and eddy current brake is not a combination made in heaven and is the source imo of most problems with this table. The marked influence of line voltage on speed is not one of its more charming attributes and forces agressive setting of the brake in terms of magnet proximity to the stepped pulley and the actual setting of the brake - under those conditions it makes a lot of noise. Running the table somewhere below the mid point of the tap setting range selected seems to be a good place to be, but line voltage has crept steadily upwards over the decades since this table was made..
I'm still not sold because I still haven't heard one that's modded. But judging from my experience with my friend's Garrard 301, at least I am no longer doubtful of what idler drive turntables are capable of. My friend is obsessive with this 301 to the point of changing to new platter and new bearing and made slate plinth for it. He got it to the point of really quiet and smooth and that lush and detailed sound with a sense of drive is really attractive. And then I got hold of a McCurdy with the giant Ashland motor so I cobbled up something simple just to have a listen and despite the rumble and noise the bass is out of this world, talk about balls to wall amazing. It made bass quality of every other turntables I've heard sounded like the musician is missing a testicle! (Perhaps with the exception of the Technics SP10 which has the tightest and most focused bass, the perfect punk rock, speed metal turntable.) Alas, I couldn't get rid of the noise and was just too lazy to go any further with it so I sold it. But at least I got a glimpse of bass heaven!
I get the following results with 120 Volt 60Hz, 1mm clearance magnet step pulley see picture
Tap 125-150 Volt < 215 ohm >
120-125 Volt + 0,6%
120-115 volt - 0,6%
120-110 Volt - 1,5 %
Tap 100-120 Volt <165 ohm>
120-125 Volt + 0,6 %
120-115 Volt -0,4 %
120-110 Volt - 1%
Speed adjustable between +3 % and -1,2 % .
With the magnet clearance at 3mm I get at 120 volt + 1,15 % min !
Seems when you lower the voltage about 10 volt the problem is solved on the 100-120 tap.
You can also use a variac to lower the voltage , Schopper did this .
But better to build clean power supply to get rid of the mains pollution higher harmonics etc.
Volken
[/ATTACH]
Attachments
Voltage control
It would be nice to have adjustable frequency output in addition to adjustable voltage output. But power supplies like that tend to cost a bit. With that in mind I've found it affordable to have adjustable voltage output, along with some isolation from the mains in the form of this Viz Isotap. As can be seen in the above photo it can adjust output from zero to 150 vac. From time to time I'll verify its output using a hand held digital multimeter. It always checks within a volt of nominal or closer.
For my TD124, (#2729) I tend to leave the output set to 120 v. With the eddy brake adjusted to the center of its range I have a strobe reading nominal all day. From time to time I may see just a very small amount (small fraction of a % deviation) of speed drift on the strobe. I usually don't adjust this because the next time I look it will have self corrected. I presume this to be a response to mains supply variation either in my building or coming to the neighborhood.
I got this one for $25.00 on ebay.
-Steve
It would be nice to have adjustable frequency output in addition to adjustable voltage output. But power supplies like that tend to cost a bit. With that in mind I've found it affordable to have adjustable voltage output, along with some isolation from the mains in the form of this Viz Isotap. As can be seen in the above photo it can adjust output from zero to 150 vac. From time to time I'll verify its output using a hand held digital multimeter. It always checks within a volt of nominal or closer.
For my TD124, (#2729) I tend to leave the output set to 120 v. With the eddy brake adjusted to the center of its range I have a strobe reading nominal all day. From time to time I may see just a very small amount (small fraction of a % deviation) of speed drift on the strobe. I usually don't adjust this because the next time I look it will have self corrected. I presume this to be a response to mains supply variation either in my building or coming to the neighborhood.
I got this one for $25.00 on ebay.
-Steve
Mine are all good, either new European made oilite or the original low hour bushings in my 124/II.. The bushings sold here in the US don't seem right to me - too loose in the bore and too much clearance spindle to bushing.
There's been a lot of discussion about how much oil to put in the housing. When I disassembled my TD-124/II originally there was oil in the housing to near the top of the bottom bushing. Knowing the owner it is extremely unlikely that she ever touched or did anything to the table. It was essentially an extremely low hours time capsule - even the Stanton cartridge on it which was newly installed around 1970 was still ok. (My understanding is this table was purchased around 1968 along with a very high end early Japanese solid state stereo receiver - which was also absolutely mint and in perfect working order.)
I've tried running with minimal oil in the housing, but prefer running it filled to just the top of the first bushing more or less as I originally found it.
I experimented with a variac on Saturday and discovered on the 124/II that it ran quite quietly and well at just 101V with about 2mm of clearance magnet to pulley. When I got the table it had over 3mm magnet to stepped pulley clearance and once I overhauled the motor back in September of 2010 the motor ran far too fast with the original brake setting. The noise with the thing cranked to near minimum speed at 1mm magnet spacing is a bit obnoxious, allowing it to run a bit fast or reducing the line voltage to allow a more centered brake setting results in substantially less noise. I've ordered a small toroid, and plan to wire it to buck the line voltage somewhere between 6 - 12V, I can add some more windings if necessary. My goal would to be run it between 105 - 108V based on my experiments over the week-end - this should be achievable since my line voltage varies only a few volts over the course of the day.
I suspect there is more to the story than just higher line voltages, in the time my table was made and sold here the standard line voltage was 117V, today it is 120V.. Mine rarely exceeds 120V since I have started monitoring it and generally ranges from a low of 116.5V to a high of 120.0V - which is probably just a few volts higher (if at all) than it would have been 50yrs ago, and still the table runs far too fast without adjusting the brake to an extreme. This leaves me suspecting a couple of things like belt thickness, mis-information about lubricant viscosity. Motor bearings to the best of my ability to check are fine on both tables.
I will say that I noted slightly more drag with elliptical and conical styli than I do with the replicant and line contact styli on the two cartridges I currently use as I no longer have to compensate for drag since I changed cartridges.
There's been a lot of discussion about how much oil to put in the housing. When I disassembled my TD-124/II originally there was oil in the housing to near the top of the bottom bushing. Knowing the owner it is extremely unlikely that she ever touched or did anything to the table. It was essentially an extremely low hours time capsule - even the Stanton cartridge on it which was newly installed around 1970 was still ok. (My understanding is this table was purchased around 1968 along with a very high end early Japanese solid state stereo receiver - which was also absolutely mint and in perfect working order.)
I've tried running with minimal oil in the housing, but prefer running it filled to just the top of the first bushing more or less as I originally found it.
I experimented with a variac on Saturday and discovered on the 124/II that it ran quite quietly and well at just 101V with about 2mm of clearance magnet to pulley. When I got the table it had over 3mm magnet to stepped pulley clearance and once I overhauled the motor back in September of 2010 the motor ran far too fast with the original brake setting. The noise with the thing cranked to near minimum speed at 1mm magnet spacing is a bit obnoxious, allowing it to run a bit fast or reducing the line voltage to allow a more centered brake setting results in substantially less noise. I've ordered a small toroid, and plan to wire it to buck the line voltage somewhere between 6 - 12V, I can add some more windings if necessary. My goal would to be run it between 105 - 108V based on my experiments over the week-end - this should be achievable since my line voltage varies only a few volts over the course of the day.
I suspect there is more to the story than just higher line voltages, in the time my table was made and sold here the standard line voltage was 117V, today it is 120V.. Mine rarely exceeds 120V since I have started monitoring it and generally ranges from a low of 116.5V to a high of 120.0V - which is probably just a few volts higher (if at all) than it would have been 50yrs ago, and still the table runs far too fast without adjusting the brake to an extreme. This leaves me suspecting a couple of things like belt thickness, mis-information about lubricant viscosity. Motor bearings to the best of my ability to check are fine on both tables.
I will say that I noted slightly more drag with elliptical and conical styli than I do with the replicant and line contact styli on the two cartridges I currently use as I no longer have to compensate for drag since I changed cartridges.
The Oilite sleeve bushings I've been buying (McMaster-Carr) tend to have correct operating clearances. Over the past 5 years I've purchased something like 10 bushing sleeves from McMaster-Carr. I measure these before installation using Mahr gages for the Id and outside micrometers for the OD.
I've observed it typical that there will be .001" of press between the housing bore and the sleeve OD. But these bushings press in with moderate pressure due to the very soft material properties. I've also observed that the sleeve ID will shrink .001" once properly installed into the housing. And this results in a useful operating clearance.
I suspect that McMaster is sourcing these bushings from Oilite in the UK. But can't prove it. And it may be that the quality of their supply might vary from one batch purchase to the next.
One thing that may be scary about trying the McMaster sleeves is that their table of tolerances for these shows a rather large amount of tolerance. More tolerance than is proper for this application. However, in practice, I've seen that my samples have been held to very close tolerances to nominal (wanted) sizes. (.001" press on the sleeve OD and .001" extra clearance on the ID, which takes up after installation.) The samples I have had here all check within A few tenths (+/- .0003") of each other.
-Steve
Oil/belts/Supply Voltage
After a couple of days I would have to say the 30wt oil is probably a waste of time, while it did slightly increase drag it did not make enough of difference IMO to make the effort worthwhile unless you are curious.
I'm giving up on the additional drag idea, and I am going to lower the voltage to the motors in both of my TD-124 to perhaps 110V or less..
I backed off the magnets, and fully warmed up both tables now run too fast at 118V, and fine at 110V or so.
I tried a few other things I am not going to share since they essentially didn't work.
I have more or less put to rest that a 50yr old OEM belt performs any better than a modern belt, after several months running one on the older table I can categorically state it has the same speed and noise related problems as the newer table and is actually slightly noisier.
I now understand why this table is not universally well regarded having lived with one for nearly 4yrs. It's a PITA if you just want to play records and not do maintenance on a frequent basis. Yes, it sounds good if you work at it, and have plenty of time and money to invest, but neither are unlimited. I will start a thread on the Garrard 401 that came to me last spring when I finally get to working on it. Or maybe I should just go get a couple of SP-10s and sort them out. I'm tired.. lol
WRT the loose fitting oilite bushings I was mentioning a few posts back, I meant ones purchased from U.S. sellers on eBay, I didn't mean ones acquired from an industrial jobber. The ones from Spain incidentally work just fine.
After a couple of days I would have to say the 30wt oil is probably a waste of time, while it did slightly increase drag it did not make enough of difference IMO to make the effort worthwhile unless you are curious.
I'm giving up on the additional drag idea, and I am going to lower the voltage to the motors in both of my TD-124 to perhaps 110V or less..
I backed off the magnets, and fully warmed up both tables now run too fast at 118V, and fine at 110V or so.
I tried a few other things I am not going to share since they essentially didn't work.
I have more or less put to rest that a 50yr old OEM belt performs any better than a modern belt, after several months running one on the older table I can categorically state it has the same speed and noise related problems as the newer table and is actually slightly noisier.
I now understand why this table is not universally well regarded having lived with one for nearly 4yrs. It's a PITA if you just want to play records and not do maintenance on a frequent basis. Yes, it sounds good if you work at it, and have plenty of time and money to invest, but neither are unlimited. I will start a thread on the Garrard 401 that came to me last spring when I finally get to working on it. Or maybe I should just go get a couple of SP-10s and sort them out. I'm tired.. lol
WRT the loose fitting oilite bushings I was mentioning a few posts back, I meant ones purchased from U.S. sellers on eBay, I didn't mean ones acquired from an industrial jobber. The ones from Spain incidentally work just fine.
I get a chuckle out of that paragraph.
I feel your pain! I gave up on the SP-10 too after living with several for over a decade. Since this is a 124 thread, I'll keep it brief. It has a clinical signature that's hard to get rid of and all the plinth making is not going to change it unless you're savvy with servo circuitry which I am not. There are better DD candidates to tinker with that have more fluid and "analog" sound. Playing violin solo on a SP10 is like dental flossing your ears.... with steel! It sounds great with rhythmic music but any flowing breathing sound is blunted by its sterile signature. It was such a workhorse though and maintenance free and at the time I listened to a lot of punk rock and metal so it worked fine but as my musical taste expanded it no longer could satisfy me sonically. YMMV.