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Thorens TD-124/II restoration / upgrade

Paul R said:
I can't figure out from the picture and the online wiring diagram whether that is 'correct' or not.... But if it's coming good at 200v it's probably right.
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I'm pretty certain all is how it was made, this deck had no evidence whatsoever of being tampered with when I bought it. No marks on screw-heads, no fresh-looking solder, just everything under a similar level of grime underneath. I've no idea if the resistor in the pic is in spec, but IIRC that's the only 'component' aside from the spark suppression cap (which I have replaced with the one Schopper sell).

Paul R said:
Both solutions are a bit unsatisfactory, the deck should be right at UK normal mains, the contemporary reviewers didn't suffer the problem.
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I agree, though to my mind I've ruled just about everything out now. I've owned three complete TD-124s (a Mk 1 and two MkIIs). The Mk 1 was the quietest, but needed a respray if you are as picky / OCD about condition as I am. The other Mk II struck me as about the same as this one, so close as to make it not worth the effort of swapping parts about - I actually bought it thinking the top platter was flatter than the one I had, but it wasn't. I made a nice boxed pre-Imp 3009 out of that deal, so not too bad though. I've also got three step-pulley wheels and another on the way (I've just bought the one originally from the newly fitted chassis just on the off-chance they were selected) and I've three idler wheels plus a load of other bits such as arm-boards, platters etc etc. My conclusion is it's just a noisier deck from an acoustical perspective than a well setup Garrard or Lenco (both of which are simpler), though thankfully this noise doesn't seem to translate into actual rumble. It also needs to be restated that I'm using a very lightweight Ortofon-style hollow plinth. I suspect the acoustic noise level would all but vanish if it was mounted in a massive block of slate or granite. If I ever decide to make the 124 my main deck that's the route I'd go.

PS I'll be having a big TD-124 spare parts sale very soon! I only intend to keep one of everything, though I'll probably hold onto the original platters just for authenticity / final resale.
 
I've no idea if the resistor in the pic is in spec
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I'm pretty sure that's a dropper for the neon that illuminates the strobe, so not particularly critical.

Something like one of these, http://www.toolbox.co.uk/digital-vernier-calipers-16488-0000 will let you measure the pulleys to a satisfyingly precise looking number of digits. Or at least confirm whether the various pulleys vary much.

One thing that popped into my mind was belts and belt tension, if the current belts are thicker or the tension less then the speed will rise.

Paul
 
Shuggie said:
I have found, using my Martin Bastin PSU, that the TD124 needs something like 230v to retain its vibrancy and 'drive', otherwise if the voltage is reduced further, it just sounds very dull. Luckily, the Bastin PSU has a frequency adjuster, so it's easy to set the voltage for best sound, then bring the speed down with the frequency knob. The Swissonor PSU appears to have just one control for voltage adjustment, so it would not do for me.

Tony - you could try using a Power Inspired AG500 or AG1500 mains regenerator, since the output voltage is configurable.
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Do you have a picture of the Martin Bastin unit that you could share?

The units manufactured by Hanze Hifi in the Netherlands could also be an option - they appear to have one with just the voltage adjustment and another with both the voltage and frequency.

20121107120133_HAT.jpg


RTEmagicC_91.JPG.jpg


And then there is the Sound Carrier Universal Turntable PSU - although this has voltage adjustment only:

turntable%20power%20supply%20l.jpg


All of the above are designed to work with the "big motor TTs" such as the 124, 301 and 401.

Br,
Teme
 
Tony L said:
Any of our electronics-literate folk care to speculate what might be in that PSU conceptually, i.e. how exactly would it control the motor speed? Are we looking at a very fancy variac here or is it likely to be doing something with mains frequency too?
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The Sound Carrier website says:

Universal Turntable Power Supply delivers controlled, stabilized
and adjustable power to synchronous turntable motors. Speed is
frequency controlled and fine adjustments are possible to any
speed. The input circuit is a rectifier consisting of a transformer,
diodes in a Graetz circuit and an integrated voltage stabilizer. This
is followed by an oscillator with 40-200Hz frequency regulation to
adjust RPM. The signal from the oscillator is pure, undistorted and
free of power noise. Then a transformer increases the voltage to
the proper value needed to drive the motor. This power supply is
dedicated to lovers of vintage turntables preferably from Lenco
and Garrard but it can drive any synchronous motor. Speed is
selectable at 331/3, 45 and 78 RPM and can be fine-tuned. Output
voltage is regulated from 180-230V for lowering unwanted motor
vibrations and is confirmed by the plate-mounted analogue volt
meter. 115 or 230 V input voltage is set on the internal PCB.
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http://www.sound-carrier.com/proizvodi/30e.htm

Don't know if this helps at all.

Br,
Teme
 
Thanks for that. I don't understand how the one with three speeds would work, does that imply you just leave the deck on one speed and shift from the PSU?
 
Teme said:
Do you have a picture of the Martin Bastin unit that you could share?
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The Martin Bastin PSU is the small nondescript box sitting under the rack. The left hand knob adjusts frequency; the right hand knob adjusts output voltage from a maximum of the incoming mains voltage down to below 100v. I have the voltage set to around 220v, which allows me to reduce platter speed with the frequency knob, without any eddy braking (I have removed the magnet). The PSU is an older model, now replaced by one that can also supply low power equipment like CD players:

image_zps2d7f325d.jpg


This is my TD124, fitted with a prototype alloy armboard (the bubble level is inaccurate and needs adjusting):

image_zpsaf095950.jpg
 
Interesting. How much is the Bastin PSU?

I've noticed the spirit levels are a little off (based on a sample of four decks/chassis) - they are probably accurate enough, but I still prefer levelling via the platter.
 
There was also Ben Duncan's thingy, the Pure Cycle, and I'm sure it was available in a version with enough oomph to drive a Garrard etc. Somewhere I've got the schematic - it's a full-on regenerator using regulated rails and a poweramp to drive an output transformer.

<googles>This product, here:
http://www.britishaudio.co.uk/PCYFLY.html
 
Tony L said:
Interesting. How much is the Bastin PSU?

I've noticed the spirit levels are a little off (based on a sample of four decks/chassis) - they are probably accurate enough, but I still prefer levelling via the platter.
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The current version is much bigger, is called the Sinosaur and costs £600. There are some details at http://www.decoaudio.com/deco_audio_ttpsu_ac.html.html . I was very lucky to get one of the last of the old model at substantially less than that figure.

Edit - John beat me to the link!
 
I'm glad to hear that your 124 is back from its extended holiday Tony , sorry to hear though, that you appear not to have received good value for money on the service; I just wish that my Lenco would come back - it's been away for three months now..
 
wylton said:
I'm glad to hear that your 124 is back from its extended holiday Tony , sorry to hear though, that you appear not to have received good value for money on the service; I just wish that my Lenco would come back - it's been away for three months now..
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TD-124s plus any degree of OCD / perfectionism means 'not cheap at all' IME.

Where is your Lenco vacating?

I've decided to buy a Martin Bastin PSU. To be honest I should have bought one years back as I'm certainly going to be keeping one of the two decks (301 or 124) for the rest of my life, so it makes sense to max it out (the PSU will work on either). The 124 runs beautifully quietly when the eddy-brake is set at it's minimum so I'll follow Shuggie's lead and take the magnet out of the 124 when the PSU turns up and do away with the eddy-brake entirely. There's a waiting list so it may be a good month or two before it turns up.

PS I've started a TD-124 parts listing here in the pfm Record Shop as I've got far more than I'll ever need now!
 
It's very possible that a small amount of brake will improve the sound, certainly worth trying before discarding.

Paul
 
wylton said:
It's at NWA.
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Oooh, nice new slate plinth time?

Paul R said:
It's very possible that a small amount of brake will improve the sound, certainly worth trying before discarding.
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I'll give it a go for sure, though I have to admit there are few things on this earth I hate more than TD-124 eddy-currenrt brakes. It seems designed from ground up to add noise and vibration!

Markus S said:
Excellent. Please try it on the 301 soon as I've been looking at that very option for my 401.
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Will do. Will be a good while before I even get it though as there's certainly a waiting list. Are you enjoying the 401?

The Bastin PSU is a 'mains regenerator', though I'm not to clear about that term. I assume it enables adjustment the speed via mains frequency rather than simply killing the voltage and losing torque? If so I have very high hopes for it. To my mind the torque is the 'thing' about idler decks, not the eddy brake, as the Lenco hasn't one yet has pace, rhythm, drive etc with the best of 'em. I'd argue the Lenco's conical motor shaft was the most elegant solution to speed adjustment of any, it's just brilliant thinking.
 
Yes, the Martin Bastin PSU is a 'regenerator', so it can adjust motor speed by both voltage and frequency, but my understanding is that the voltage bit is critical to maintain torque, but dropping voltage does slow down the TD124 motor. No doubt someone who knows about these things will be along to explain.

One thing to be aware of with a PSU such as this is that it renders the standard neon strobe useless, because that neon bulb will show the frequency that you're feeding the motor, not the 50Hz or 60Hz necessary for using the built in strobe markings. I replaced the neon strobe with an LED one from KeyStrobe, which has its own quartz reference, so that's fine (the strobe markings are completely clear now, which is a bonus). You can, of course, set the platter speed using any turntable strobe disc and hand held LED zapper.
 
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