Restoring and Improving A Thorens TD-124 MKII

[missouricatman]

Originally Posted by kevinkr

Hi Jim,
There were two basic variants (plus a number of minor running changes that probably aren't well documented if at all) of the stepped pulley used on the TD-124, I am not exactly sure when the bronze top bushing version was phased out, but I would guess somewhere in the range of 20000 units. I just purchased a unit with a serial number in the 22K range and it has the later version, units I have rehabbed up to serial numbers in the 12K range have all had the sintered bronze top bushing version.

I surmise that the change was made to enhance longevity and improve performance in the face of wear, the newer version has two sintered bronze bushings in the chassis along with the height adjustable thrust-plate. The bushings are replaceable in the event that they have worn out.

A machinist should be able to quickly machine you a jig to straighten out your stepped pulley shaft if this is indeed the problem. I will not know for quite a while what parts I will ultimately sell, but if I do end up with a stepped pulley I need to sell I will keep you in mind. There was one recently on eBay, but it is not there now - I believe the auction expired and it may yet reappear, I searched and did not find one currently listed.

kevinkr- Thanks for the info. Interesting isn't it, that the more you learn about a piece of equipment, the more you discover variations introduced throughout the years. I do hope to get back to mine soon (well early 2013 at this rate). At the moment, DIY skills in basic carpentry are being put to work, as I've got a new room in the attic that needs to be framed and insulated before it gets much colder. We're starting to hit the 20's overnight at times, so that job's going to keep me hopping for awhile.

[kevinkr]

Hi Jim,
Sounds like its even colder out there than here, we're expecting high 20s tonight, but living close to the sea as I do may moderate it a bit.


The basic design of the TD-124 was pretty solid, notwithstanding the nylon bushed main bearing in earlier units which usually seizes up, motor variations and the stepped pulley design - all of which are easily addressed if necessary during restoration.

Looking forward to hearing more about your table restoration..

[kevinkr]

Hey Jim,
Here is a stepped pulley that was just listed on eBay:
Thorens TD124 124 MKII Tunrtable 100% ORIGINAL Stepped Balanced Pulley | eBay

No affiliation with the seller, the price at least seems reasonable.

[kevinkr]

The fun begins soon, the donor TD-124 from NYC arrived via parcel post this morning. Yeah!

[kevinkr]

Surgery occurred yesterday afternoon and evening, I regret to mention that in all of the excitement I forgot to take pictures. The surgery was not entirely smooth, but concluded successfully..

I did in the proceedings manage to loose one of the balls from the speed setting detent mechanism, but for now one will suffice.

The only other area of difficulty was setting up the eddy brake adjustment knob and linkage where the inner shaft is about 100 mils or so shorter than required to allow the installation of the C clip with the knob bottomed. Turns out the slop is instrumental to the mechanism working properly or at all, took me a while to understand this, and a look at my TD-124/II confirmed this. So word to the wise - remove not the shaft from this knob if possible otherwise some iteration will be necessary. It also works backwards - I suspect I need to turn the linkage over. I will do this once I get a replacement ball for the detent mechanism since this has to come apart to install the ball.

The sharp eyed amongst you may notice I have an SPU GM E II on a 3009 Series II, no this is not an illusion. Adding an additional brass weight which a friend made to my specifications makes this possible, IIRC this weight weighs about 30gms.. It works well and sounds good.. (I'd recommend this bodged combo over anything else I've put on this arm.)

[KBK]

Ah, the charms of fully realized instantaneous torque.

That a record requires a level of zero micro-cogging or zero micro-distortion in rotational torque/time...in the platter drive and connectivity to the record itself.

And this... across a basic infinity of complex lateral shifts in stylus motion, which, as a set of complex and never repeating near infinite series of harmonics, all delivered in perfect time, across all complex functions (and in torque stressing of the drive mechanism)...well..apparently this understanding was not lost on the Thorens people way back when.

Only under such aspects can the full peak levels, in proper context each, and within context to others.. can this aspect of pefection in peak values occur.

This is fundamental in the extreme, as the ear hears only by this mechanism. That's it. the other linear measured 90%+, it never hears or knows is there. Meaningless and unheard, by the ear. All critical.... is those peaks and their relation to one another, as a harmonic set.

[kevinkr]

Not shown in the previous pix is my pride and joy ( ) a very mint TD-124/II. It was almost as if it had spent the past 40yrs in a time capsule - which in a sense it had since it was in a console with a lid that the owner never opened after the very early 1970s..

The motors in these tables vibrate pretty badly, but the belt, good motor mounting bushings and a massive plinth keep the whole thing pretty quiet. Careful tweaking does help. Lots of torque comparatively speaking, when warm it is fully up to speed in about 1 revolution of the platter.

[analog_sa]

Originally Posted by kevinkr

a massive plinth keep the whole thing pretty quiet.

Never really bought the mass loading concept. Especially after trying to live with a Trio L07 for a while.

So, this summer at the prompting of a friend and the insistence of 20kg worth of slate in my basement i did some experiments.

Same result: hi-mass, slate, stone - definitely not for me, thank you. Robbing music of nuance, microdetails, tunefulness... Luckily i wasn't the one cutting the slate as it was one no-fun exercise.

What we ended up with was just an open frame construction, very stiff but still not particularly light. Polymer mushroom decouplings in the vertical plane and roller-block type couplings to isolate the horizontal movement and couple vertically the base. Best sound from a 124 to my ears.

[kevinkr]

Very cool, looks like a lot of thought and experimentation went into that set up..

The slate plinth has worked well for me so far, no lack of dynamics, tunefulness, or micro-detail, and in addition there was a noticeable reduction in background noise. I am however running a very different set up with a 12" high mass Schick arm with an SPU which is not mounted on the TD-124.

Based on my experience with several different arms on this table I would not be the least bit surprised to find out that different plinth approaches might work better with one type of arm than another. What I have works well with the specific set up I have, and for my specific tastes and expectations. I've had a couple of vintage wood plinths which while not horrible clearly weren't wonderful either.

When time and money permit I may experiment with other approaches particularly as I have the second table to experiment with.

The table sits in a heavy rack on a concrete floor, but the set up lacks a certain elegance I think which is fairly obvious from looking at yours.. I'm assuming underneath it all is a diy vibraplane..

[analog_sa]

Originally Posted by kevinkr

the set up lacks a certain elegance I think which is fairly obvious from looking at yours.. I'm assuming underneath it all is a diy vibraplane..

ha, ha. Elegance Thanks for the kind words. Far from it really but this is around attempt 3 following the same idea. The first two had either too much steel or too much wood. One of the most important "discoveries" was that it had to rest on 3 pillars and there is a convenient threaded hole on the left side... obviously i am not using the top platter and corresponding "brake".

The slate plinth also showed that the worst possible sound was achieved with the chassis resting directly upon the slate surface. Having rubber or cork in between definitely improved things.

What is wrong with the current setup, at least as far as i can tell, is that is way too tall and the centre of gravity correspondingly too high.