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Old 18th November 2010, 06:45 PM   #111
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Vibration Mounts eStore Cylindrical Rubber Anti Vibration Mounts Rubber Neoprene Urethane Sorbothane Silicone Gel Ring Mounts

The above link should match up to photos of the motor grommets in your photos.

As we try different grommets, it becomes possible to compare the effects. Basically, any of the ones currently available to us will be an improvement over the 40 yr old melted ones that we typically see prior to beginning a project. At least there is a choice.

The ones from Mirko work well too. They are the firmest/hardest of the three types I've tried. Using a stethoscope, these seem to keep the vibes out of the chassis as well as any of the others. I'd imagine one would have to get more serious about measurements, by electronic means with recorded values, before we could really know which ones work the best. And it might be useful to measure wow/flutter as well as rumble while making these comparisons.

I've also been using new replacement idler wheels from Mirko. These aren't perfect, but they do have fresh rubber, new bronze bushings and spin concentric. I have found, in the three Mirko idlers that I have tried, that it is necessary to adjust height of the idler wheel to match the step pulley lands. Or in the case of the MkII, it is easy to adjust vertical position of the step pulley to match up to the idler wheel.

But the results have been audibly better in my experiences. 40 yr old idler rubber versus new idler rubber....with fresh bronze bushings.

-Steve
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Old 18th November 2010, 06:48 PM   #112
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Default FD81 kit from Schopper

Steve,
Schopper sells their long motor mounts/bushing kit for about $200. That's a lot of money. Someone on ebay sells the longer MKII motor rods for $125 or BO but no bushings. Do you know if Schopper sells only the motor mount bushings? If not, where can they be sourced? I currently have the gels on my MkI motor. Your observations and comments on their possible behavior got me thinking.
Thanks,
David
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Old 18th November 2010, 07:28 PM   #113
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Quote:
Originally Posted by user510 View Post
Vibration Mounts eStore Cylindrical Rubber Anti Vibration Mounts Rubber Neoprene Urethane Sorbothane Silicone Gel Ring Mounts

The above link should match up to photos of the motor grommets in your photos.

<snip>

-Steve
Hi Steve,
I looked after your post referencing Vibration Mounts and the "Metric Spring Mounts" are the closest, but they aren't quite the same. Here is a link (currently down, wasn't a couple of weeks ago) to the manufacturer: http://www.geltec.co.jp/english/product/pro_02.htm It is the A2 type formulation.. V10261MA2 is the part number for these bushings, and currently it is not available using the search tool at vibration mounts. The appearance is a quite bit different too. They are a more squared off than the parts shown and don't have the collar either.

Mirko's idlers are somewhat controversial, but I was thinking at some point i would probably spring for one of these although for the moment the original seems to work fine.

The cold weather motor performance is a bit concerning. Can't wait for it to get really cold here as I expect the motor will then not start at all.. I am thinking about changing to a different lubricant in the motor. Still works absolutely fine once warm, and speed is completely stable, but I think I will be pulling it apart again shortly to clean it and change the lubricant. This might be why a lot of E50 motor rebuilders run these for a week and then tear them down again. I'm approaching that number of hours. Nothing more than a nuisance, and perhaps I don't need to do anything but recheck the bearing alignment.. (The motor is fully rebuilt, and about as quiet as possible.)

I guess I should expect this with a table that sat unused for 4 decades..

Our power here is a badly clipped sinewave, so bad in fact that 120V decorative neon lamps don't work here at all without a step up transformer. Line voltage measures over 118Vrms all the time, but the waveform is distorted - thinking this might have impact on start up torque.

I employ voltage regulation in all of my electronics so as long as they don't drop the performance of my signal chain is not affected. I only noticed the issue when my wife complained that some of our neon lamps no longer worked and i investigated - this was after some of the transformers in our neighborhood were replaced with modern ones. (Apparently the new ones run on the verge of core saturation or perhaps are saturating on the peak..) The waveform is bad at all times of the day..

I'm going to order a belt from Octave Audio as I would expect given their TD-124 expertise that this belt fits and runs quietly. Hopefully this is not the same as the Thorens belt I purchased recently from Thakker which clearly has an issue.
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Old 18th November 2010, 07:38 PM   #114
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Quote:
Originally Posted by TerribleT View Post
Steve,
Schopper sells their long motor mounts/bushing kit for about $200. That's a lot of money. Someone on ebay sells the longer MKII motor rods for $125 or BO but no bushings. Do you know if Schopper sells only the motor mount bushings? If not, where can they be sourced? I currently have the gels on my MkI motor. Your observations and comments on their possible behavior got me thinking.
Thanks,
David
The bushings are expensive enough that it might make sense to get the kit if you are going for the long motor mount kit..

Several sellers offer alternative bushings to Schopper on eBay..

Octave Audio has the bushings separately here:
Octave Audio - Motor-Damping-Set FD 81
These are the Schopper parts..

Mirko sells a similar but not identical part.. (See Steve's post for more on this)
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Old 18th November 2010, 10:22 PM   #115
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Kevinkr,
Thanks for the link. They are $50 for 6 grommets.
Click the image to open in full size.
The gel grommets would cost about $30 to $50 for 6. I may spend the bucks on the Octave's to compare them with the gelsClick the image to open in full size.
One more question Kevinkr, after you rebuilt your motor, how hot does it get? On my rebuilt motor, it gets so hot I can not leave my finger on the housing for more a second or so. It is very quiet and holds its speed with no problems.

Thanks,
David

Bolt Mounts &ndash; Silicone Gel Type

Last edited by TerribleT; 18th November 2010 at 10:30 PM.
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Old 19th November 2010, 01:03 AM   #116
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Quote:
Steve,
Schopper sells their long motor mounts/bushing kit for about $200. That's a lot of money. Someone on ebay sells the longer MKII motor rods for $125 or BO but no bushings. Do you know if Schopper sells only the motor mount bushings? If not, where can they be sourced? I currently have the gels on my MkI motor. Your observations and comments on their possible behavior got me thinking.
Thanks,
David
Hi David.
Mirko (sq38s) is the one on Ebay selling a MKII upgrade kit. His kit includes the grommets, clips and washers for $125. I have purchased a few of these kits and they install and work fine. It is definitely a savings over the 200 dollar Schopper kit. Although Schopper, I think, has a more interesting set of grommets.

Initially I had purchased just the grommet kit only from Schopper (# FD81) when I wanted to try one of those Papst Aussenlauffer motors on my TD124. I didn't like the sound of the TT with the Aussenlauffer motor and went back to the E50, but then purchased a MKII conversion kit from Mirko to update my MK1 motor suspension. That is why I have an extra 6 grommets around.

I have also installed a couple of MKII conversion kits on TD124 players for other people. The machining on the posts is good. The grommets, clips and washers fit correctly.


Quote:
Hi Steve,
I looked after your post referencing Vibration Mounts and the "Metric Spring Mounts" are the closest, but they aren't quite the same. Here is a link (currently down, wasn't a couple of weeks ago) to the manufacturer: http://www.geltec.co.jp/english/product/pro_02.htm It is the A2 type formulation.. V10261MA2 is the part number for these bushings, and currently it is not available using the search tool at vibration mounts. The appearance is a quite bit different too. They are a more squared off than the parts shown and don't have the collar either.
ƒg[ƒŒƒ“ƒX THORENS model TD 124

re: above link. I remember studying the above page and another page he made showing his motor overhaul. He referenced Geltec Co. as the source for his silicon gel bushings. So I made contact with Geltec.co in Japan by email and got a reply from one of their sales people. They are the ones who directed me to vibration mounts as the outlet in North America for their silicone gel bushing product. At one time I was able to source the A2 silicon gel from Vibration Mounts. Here's a cross section view of the bushing as it would be used on the TD124:
Click the image to open in full size.

The compliance factor of the bushing is indicated by the part number that either ends in numeral 1 or numeral 2. So we would choose part number:
V10Z61MA2 that has an ID of .16 inches. The brass collar is removed from the id before using. Obviously these bushings weren't exactly designed for our application, but seem to fit up well enough. I did mention that I'm not exactly crazy about using these bushings?!!

re: powder on belt in the mkII manual.
Ahhh. So Thorens themselves were perpetuating that myth.. They might have known something. I've tried it both ways on mine, that is powder and no powder and can't hear a difference. Perhaps a very sparing amount of powder is advisable.

re: motor heat and motor vibes.
A freshly assembled motor tends to run extra warm until the upper and lower motor bearings are in optimal alignment. This I have found through my own trial and error. The better the alignment, the cooler it runs. Also, the quicker the TT comes up to speed.

I do run a freshened motor in for a week or thereabouts, then re-align the bushings again. This seems to result in a very stable, quiet and reasonably cool running motor.

I"ve been using 20 wt lube for a couple of years and prefer it year around.

re: platter mats.
I've been using the original rubber mat after cleaning the thing in the kitchen sink using warm water and suds and soft brush. Then pouring boiling water over the rubber mat to further soften it. Seems to freshen it up a bit. I have also used auxiliary mats on top of the rubber mat in order to distance the moving coil cartridge above the iron platter. After a time I found that with the cartridges I'm using (DL 103R, Shelter 501-II, Ortofon Jubilee) that there wasn't any problem with the magnet pulling the cartridge down toward the platter. This I tested using a vtf scale at various points along the arc path. So I stopped using the auxiliary mat and found that there is indeed a sharper dynamic and better low frequency authority available by simply using the original mat. IN my case, noise floor is still quite low and not noticeable.

That much said, I do feel that there is room for someone to develop a better mat for this TT. IT is just that the mat will need to be of the kind that fits exactly like the original. That is it is clamped into place by the 45 adapter/collar.

-Steve

Last edited by user510; 19th November 2010 at 01:18 AM.
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Old 19th November 2010, 01:16 PM   #117
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Quote:
Originally Posted by TerribleT View Post
Kevinkr,
<snip>
One more question Kevinkr, after you rebuilt your motor, how hot does it get? On my rebuilt motor, it gets so hot I can not leave my finger on the housing for more a second or so. It is very quiet and holds its speed with no problems.

Thanks,
David
@ David
It ran quite hot for the first few hours after the rebuild, and is still rather uncomfortable to the touch after an hour or so of operation, although not nearly as hot. My line voltage averages 118V..

Steve's comments about bearing alignment are spot on, I also found this to be quite true.

Noting that I have not tried this: The turntable is normally set to the 100V - 120V setting for North America, in the event that your line is constantly and appreciably higher than this you might want to try the 125 - 150V motor tap instead. Note that torque will probably be reduced to some extent, and the calibration of the eddy current brake might not allow you to run at the proper speed. Might also affect some of that drive the TT is noted for. Try at own risk, and don't mess with the eddy current brake calibration when the motor and table is cold!

@ Steve
Interesting comments/conclusions on the mat. I have reluctantly (maybe not so reluctantly) come to the conclusion that the stock mat is pretty good if not quite perfect. I think I am getting used to its colorations, and for the moment I find it satisfactory. I'd be very interested in hearing about further insights in this area if you have them. Again both Mirko and Schopper offer replacement mats, so far I have not been able to find any evidence as to whether or not they sound better than the stock mat. Your suggestions for mat reconditioning sound good, and I think I might give the boiling water idea a try as well. (I did the rest as you did)

I have noted that Schopper sells an "improved" top platter and am mildly curious as to whether it in any way improves on the original - mine is perfect so there is no impetus to replace it.

FWIW I think I will try the Schopper motor isolation mounts at some point, so far I have not had any issues with the current ones. Based on measurements however I did install the big end of the geltec bushing on the motor end and the little one (which is tiny) in the groove on the top of the chassis. The second bushing IIRC was installed with the same orientation, but I think this is not critical. I did not observe any more deflection of the motor assembly with the belt installed than I did with the older bushings which have not hardened up, but probably aren't ideal either. (I still have them) One thing of note is that the motor height might not be absolutely identical with the stock bushings and I did end up tweaking the motor pulley height slightly in order to make sure it and the intermediate pulley line up properly. I'm of mixed feelings about this, but I haven't noted any problems either.

With regard to the talc issue my suspicion is that it would be of some benefit with the very stiff modern Thorens CB965 replacement belt in reducing the noise made as the belt enters and leaves the circumference of the intermediate pulley as in theory it should reduce the belt adhesion as it leaves the end of the pulley.. This is of course a complete swag as I haven't tried it yet.

One thing I think I haven't emphasized is that I really appreciate the fact the magnetic fields from the motor do not interfere with the cartridge at any point during play. This was a huge problem with the TD-125 towards the inner half of a record and was the one reason why ultimately I decided after quite a few years of use that it was unsatisfactory, listening to a properly running TD-124 provided lots of other justifications beyond this.. (A number of other belt drives with AC motors that I have used also had this issue)
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Old 19th November 2010, 02:28 PM   #118
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Touching further on the motor pulley alignment issue I have attached a capture of the Thorens TD-124 MKII owner's manual (p.7) on pulley alignment. Note that they indicate that the pulley may be seated as much as 1/64" below the top of the shaft..

The two decks I have looked at (both MKII) had pulleys mounted with the shaft recessed by 1/10" or more. (Not disturbed since built)

What is important is that belt rides on the center of both pulleys..

When (re)installing the pulley tighten the black grub screw first and then the silver one.
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Old 19th November 2010, 06:07 PM   #119
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Quote:
Touching further on the motor pulley alignment issue I have attached a capture of the Thorens TD-124 MKII owner's manual (p.7) on pulley alignment. Note that they indicate that the pulley may be seated as much as 1/64" below the top of the shaft..

The two decks I have looked at (both MKII) had pulleys mounted with the shaft recessed by 1/10" or more. (Not disturbed since built)

What is important is that belt rides on the center of both pulleys..

When (re)installing the pulley tighten the black grub screw first and then the silver one.
Right. What is important is that the belt rides on the center of both pulleys. Although it will unless there is a really large height misalignment between the driving and driven pulley crowns. The crowned shape of the pulleys tends to retain the belt on crown center.

The 1/64th maximum feature is probably given as a general rule of thumb. Much lower and the pulley scrapes against that thin aluminum dust cover. A recessed shaft would indicate that the pulley is seated higher on the shaft than is shown in the illustration--- and is within that dimensional tolerance. Ideally, both the driving and driven pulley crowns will share the same plane.

All of this will come into play as one tinkers around with adjusting the step pulley and idler wheel alignment when one changes to a different idler wheel.

-Steve
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Old 20th November 2010, 06:18 PM   #120
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The turntablebasics belt came today and measured more or less similarly to the Thakker belt, except that it is 0.030" thick and appears if anything to be somewhat less pliant than the Thakker. I haven't run the new belt yet so I will report back when I do. I'm in no rush to do it.
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