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Thorens TD-124/II restoration / upgrade

InSides said:
You are not alone. The human eye is surprisingly susceptible to even the smallest amounts of runout, and once you see it, you can never un-see it.
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Good to hear I’m not the only one! It certainly took me a long time to find a Linn platter I was happy with, though that is accentuated by the suspension - any eccentricity will actually wobble the subchassis. I was always impressed by how good the Spacedeck was. That thing was absolutely spot on. My Garrard was really good too.

InSides said:
I would be interested in the belt you are testing, once you can share more details, as I am still struggling with the proper formulation for my drive system.
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It originates from within the pfm community. I have no commercial involvement so not for me to announce, its maker can do so whenever he’s ready. The key benefit to my mind is it is the right size for the 50Hz TD-124 pulley (there will be two different belts). All other belts from day one attempt to be a compromise that work with both the 50 and smaller 60Hz pulleys. This always means they are just way too tight on the larger pulley which impacts the motor isolation, places unnecessarily side-force on the bearings and prematurely wears belts as they run stretched. It was a dumb design, there always should have been two distinct belts as the length is so different depending on the pulley in use (the theoretically ideal length differs by about 8-9mm, which is a lot over what is only a short belt). I’m holding out before fully commenting as really the key factor with a TD-124 belt is longevity; they run very fast (motor speed is about 1450rpm IIRC) and the tight ones always start to shed and get noisy after a while. So far this one is working very well indeed and I’ll likely stockpile some when they are ready. It is very quiet so far.
 
Tony L said:
It originates from within the pfm community.
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Nice! I sincerely hope the maker is willing / able to produce other dimensions as well. No TD-124 here, but my drive configuration means I could certainly use a few different variations.
 
I’m interested in this new belt too. My Hanze belt seems to be too tight and pulls the pulley to the right so that the motor rods touch the Hanze springs leading to a ringing sound. It’s not loud at all but it is audible near the deck.
 
Hi folks,

I was intending to leave it a another couple of weeks but there seems to be so much interest in these new belts that I feel it's time to let the cat out of the bag. It's me who's behind the new TD124 belt that @Tony L has been testing.

Actually, @montesquieu has also been testing them for me too and it's not just TD124 belts, there's also a belt for the TD125/TD126/TD160/TD166 etc.

Regulars here will probably be aware of my (many) vintage CD player restorations and for several years I have been using drive belts manufactured in Germany, which I've found to be far superior to anything else available on the market.

More recently I've started to work collaboratively with this belt manufacturer and I've been helping them to develop some new products, including a small range of turntable belts.

Standard flat belts for turntables are cut from rubber strip, which is then closed with a glued join. Our belts are different, they are moulded as a single continuous circular piece with no join and therefore run more noticeably more smoothly.

They are not made from butyl or neoprene rubber either and are instead moulded from a compound which offers vastly better dimensional stability (doesn't lose its shape) and has better grip and so doesn't need to be as tight - which in turn reduces bearing wear and noise. Also it does not harden and perish in the same way as butyl rubber.

We have paid great attention to optimising the belt lengths/tension. Many turntables, including the TD124, have two different motor pulley diameters - a larger one for 50Hz mains frequency operation and a smaller one for 60Hz. The TD124 has a reversible stepped pulley which is flipped over to swap between mains frequencies. The optimum belt length is therefore different for each pulley and yet the currently available belts are sold as being 'universal' for both 50Hz and 60Hz operation and are an unsatisfactory compromise.

Our TD124 belts are being manufactured in two versions with slightly different lengths, one with an optimal length/tension for use on the 50Hz pulley and a slightly shorter one for the 60Hz pulley.

@montesquieu and @Tony L both have final prototypes of the TD124 50Hz belt which they are testing at the moment.

I'm not sending out any more free test samples but I have limited stocks if anyone wants to buy one.
 
Just adding to what Mike has said here specifically in context of TD124 ... there are quite a few issues with the available TD124 black rubber belts, either being too tight (which can be alleviated a bit with a Hanze spring set which have a bit more 'give' than the normal rubber grommets) and perhaps more annoyingly, shedding black rubber on the pulleys which needs cleaned off regularly with alcohol. Either way the result is unwanted noise, and the tightness can potentially also strain the motor/pulley bearings.

Mike kindly asked me to try out a couple of prototypes of his moulded blue belt, and the final version. The new belt is not as tight as the rubber belt, especially with the Hanze mod fitted, which made me worried initially when I was fitting it, but I needn't have been concerned: the level of grip is perfect. Indeed despite the lower tension, it actually seem to have more friction than the rubber belt.

Interestingly, I actually thought the lower tension also had some sonic benefits. Many people are surprised that the 'idler' TD124 is actually a belt drive. But it is the case that the motor wheel drives a stepper pulley through a short belt, isolating the motor from the idler wheel. In my view this is what makes the TD124 the best idler of all, and notably better than the Garrard arrangement where the idler is driven mechanically - you get all the drive and energy of an idler, with potentially greater subtlety from lower motor noise coming through (the benefits of both idler and belt drive).

Regarding the sonic benefits: I had a perception in my system that the new belt delivered a more musical sound. I could theorise that the lower tension further upped the reduction in vibration transmission; or that the extra friction was having some benefit - or indeed that there was a bit of both going on. Anyway, I'm delighted with this belt and would recommend it to TD124 owners without hesitation.

I also noted that after a couple of weeks' use, there was precisely no residue from the blue belt on the pulley wheels. No more q-tips and alcohol before a listening session. A major plus in my book.

One thing to note - the belt was a bit noisy when first put on, it gave quite a bit more pulley noise than the rubber belt and initially I was really quite concerned about this. But after a few hours the noise went away and it was dead quiet (see video after a few days' running). So I would urge patience on any purchasers while it runs in over the initial first day or two.

The video - note here that the microphone is only a few cm away from the mechanism, and even so is still extremely quiet. (Most of what you can hear here is me breathing!).

 
montesquieu said:
Just adding to what Mike has said here specifically in context of TD124 ... there are quite a few issues with the available TD124 black rubber belts, either being too tight (which can be alleviated a bit with a Hanze spring set which have a bit more 'give' than the normal rubber grommets) and perhaps more annoyingly, shedding black rubber on the pulleys which needs cleaned off regularly with alcohol. Either way the result is unwanted noise, and the tightness can potentially also strain the motor/pulley bearings.

Mike kindly asked me to try out a couple of prototypes of his moulded blue belt, and the final version. The new belt is not as tight as the rubber belt, especially with the Hanze mod fitted, which made me worried initially when I was fitting it, but I needn't have been concerned: the level of grip is perfect. Indeed despite the lower tension, it actually seem to have more friction than the rubber belt.

Interestingly, I actually thought the lower tension also had some sonic benefits. Many people are surprised that the 'idler' TD124 is actually a belt drive. But it is the case that the motor wheel drives a stepper pulley through a short belt, isolating the motor from the idler wheel. In my view this is what makes the TD124 the best idler of all, and notably better than the Garrard arrangement where the idler is driven mechanically - you get all the drive and energy of an idler, with potentially greater subtlety from lower motor noise coming through (the benefits of both idler and belt drive).

Regarding the sonic benefits: I had a perception in my system that the new belt delivered a more musical sound. I could theorise that the lower tension further upped the reduction in vibration transmission; or that the extra friction was having some benefit - or indeed that there was a bit of both going on. Anyway, I'm delighted with this belt and would recommend it to TD124 owners without hesitation.

I also noted that after a couple of weeks' use, there was precisely no residue from the blue belt on the pulley wheels. No more q-tips and alcohol before a listening session. A major plus in my book.

One thing to note - the belt was a bit noisy when first put on, it gave quite a bit more pulley noise than the rubber belt and initially I was really quite concerned about this. But after a few hours the noise went away and it was dead quiet (see video after a few days' running). So I would urge patience on any purchasers while it runs in over the initial first day or two.

The video - note here that the microphone is only a few cm away from the mechanism, and even so is still extremely quiet. (Most of what you can hear here is me breathing!).

Click to expand...

I'm very grateful for your excellent and detailed feedback Tom. Without the right people to test the prototypes this project would never have got off the ground.
 
Similar findings here. I’ve only had the final production version for a couple of days and it is only just starting to quieten down. It has a way to go, but I’m sure it will get there. I’d been running the narrower pre-prototype for a month or so and that was superb. Really good and very quiet. The quietest I’ve achieved from my deck to date. If these blue belts last well I’m sold.

FWIW I am pretty certain much of the issue with black deposits/shedding from standard belts is that they are just too tight. By running stretched means the rubber starts to crack, fracture and deposit itself on the pulleys. The argument one belt should work with both pulleys is pure idiocy to my mind. Sorry, but Thorens got this aspect wrong and I don’t care if I appear arrogant in saying that! It is obvious there is best part of a cm difference in length between the arcs formed by the different pulleys and therefore tension differs hugely. This is just basic physics. I came to this conclusion ages ago when I was ordering a variety of different sizes from Turntable Basics. The absolute minimum tension that will start the deck is the correct tension IMHO. Anything beyond that only impedes the motor suspension (see Nagraboy’s pics upthread) and transmits more noise. The blue belt allows the motor to stay nicely centred on its springs (I use the Hanze-Fi ones too).

I always give my turntable a manual push when starting it just to save stress on both the belt and (original Thorens) idler, though I can confirm the blue belt can easily start my deck (heavy iron platter, Retrotone top platter) from cold.
 
Great point Tony yes I use the Schopper heavy platter (5kg) and bearing, and Retrotone top platter too, plus a fairly hefty graphite mat! And I also give the platter a push when starting to lessen the load - though as you say, the blue belt will happily get things going on its own.
 
Nagraboy said:
The Retrotone top platter, is it just a drop in replacement for the standard one?
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Yes though you need a new centre for it as well as the platter if you want to use a different mat. If using the standard Thorens mat the original centre will fit. It's slightly thicker so you do need to adjust the VTA.
 
Interested in a 50hz version @Mike P , although I was stunned how quiet my td124 motor unit was when I bought…and then stuffed it on a shelf for last 3 or 4 years :) May motivate me to commission it finally ;)
 
The production belt has now really quietened down now after maybe 5-6 albums. I’d love to know the mechanism as to why? This way is good though, TD-124 belts usually start quiet and get noisy with time!
 
I used to clean the pulleys frequently but more recently I haven't bothered and so I live with the noise the shredded rubber generates. I've now ordered a belt from Mike and look forward to less noise and not cleaning the pulleys every now and again. If it works as described the belt will be worth every penny.
I might even try the retrotone platter at some point!
 
I’m liking the Retrotone platter, it’s upped the bass slam and dynamics without any negatives I’ve noticed. Tighter and more ‘thwack’ to drums. This 124 really is sounding good at the moment, all the effort and OCD has paid off!
 
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