Thorens TD124 overhaul

[Deleted User]

Hello,
Here's the latest project on the workbench, bringing back to life a classic Thorens TD124 turntable. The owner wants it to look like it did when it came out of the box and wants a new Linn Akito tonearm to be installed. The first step is to work on the upper section, lots of Q-tips and Flitz and plenty of elbow grease to get rid of the grunge. This table uses a combination of belt drive to rotate a stepped capstan and then power is transferred to the heavy cast iron platter via an idler wheel.
More to come.
Cheers, ken

TNHNDYMAN

cool project, looking forward to more updates and pics

PolkieMan

Those turntables are big $$$ on ebay even DOA's just for parts :cheesygrin:.

SCompRacer

Hey Ken! Nice project! The Akito is quite a nice arm. I'll be following this thread.

[Deleted User]

Thanks, Rich, next step is the platter bearing. This table is an early one and has the two teflon sleeve bearings instead of the later bronze sleeves. Anybody familiar with JB No1 oil? I believe it is a German oil company. Anybody recommend an automotive stethoscope they've used? I want to listen for bearing chatter in the platter bearing and the motor.
Cheers, Ken

gdb

Lisle on the stethoscope, mine is very sensitive and didn't cost too much. There's an ebay Thorens seller in Germany named Joel, IIRC, that sells the good oils and belts etc.

http://www.amazon.com/Lisle-52500-Mechanics-Stethoscope/dp/B0002SQYSM/ref=sr_1_11?s=automotive&ie=UTF8&qid=1349472234&sr=1-11

vc69

Are these tables really superior to a modern table? I know they are highly sought after, but the reason for that escapes me. Do they sound just that good? What gives?

gdb

Any idler wheel TT produces "rumble" is the generally accepted view of non-idler TT enthusiasts. I'd think that if they were so great.....they would never have stopped making them. FWIW, some folks collect/drive Edsel automobiles.

SCompRacer

PolkieMan wrote: »

Those turntables are big $$$ on ebay even DOA's just for parts :cheesygrin:.

Audiophiles really drove up the price of the desirable Thorens and Garrard turntables. Stick them in heavy plinths to absorb vibes and address other issues and there isn't an arm or cartridge you could not mount on it. Cost to manufacture is one of the reasons. They are belt drive killers when done right.

A fellow by the name of Jean Nantais looked at the Swiss made Lenco and did the same thing. Heavy plinths, aftermarket bearings, attention to detail. Now the beater Lencos are getting pricey and completed tables are high in asking price.

Bearings and oil Ken! Now there is a subject that can get involved.

I use a stethoscope like the one suggested Ken. It allows you to check with pin point accuracy by pressing the probe down. Be careful with the probe when you are wearing them. Bump it into something can be a loud sharp knock in your ears.

[Deleted User]

Hello,
Thanks for the stethoscope suggestions. One of the things that I believe is interesting about the hobby of audio is its willingness to reinvent its "wheels" so to speak. Some of the older participants might remember when there wasn't any audio gear being made that used vacuum tubes. Everything on every audio shelf was powered by solid state devices, only collectors who held onto classic Marantz and McIntosh products and a few others heard what everyone else had moved away from. Now I venture there are as many, if not more, companies who build with vacuum tubes than don't. The other worthwhile tendency, in audio, is to take a humble design such as the cassette, which started as a dictation device, and propel it towards perfection. The same thing happened to the phonograph record, goes away then comes back sounding better than ever.
I think it's a healthy sign, really, that what was thought up in the past and what was contributed by previous generations can have value in the present. It doesn't have to be better, although it might, it just needs to be appreciated for its own sake. I'm amazed at how unbelievably good some of the monophonic classical recordings of the 1950s sound for example. Plus it's just plain fun to resurrect something that was well made, peel off the grime and let it shine once again and if it makes beautiful music so much the better, right?
Cheers, Ken

schwarcw

Amen to that Ken! Some vintage gear are true works of art. R2Rs, turntables, and many of the vintage electronics sound very nice and look wonderful when restored to their original luster. The black plastic of many of todays electronics just don't have the visual appeal. They may sound great but I like the best of both.

I will be following this thread with interest. Ken is a skilled technician and does meticulous work. The Thorens will look and function just like the day it came out of the box.

[Deleted User]

Have Flitz wil travel, I'm taking the platter bearing and cleaning supplies to Cape May for a week's vacation. I hope I can connect with CP but not sure.
There might be a visit to Princeton Record Exchange in my future, look out credit card! That place is awesome!

PolkieMan

On a turntable like that how to you adjust the speed? Or is automatically set perfect?

SCompRacer

PolkieMan wrote: »

On a turntable like that how to you adjust the speed? Or is automatically set perfect?

To get the various speeds they used a step pulley the rubber idler pulley rides against. To fine tune speed, in the third picture, see that dark 3/4 moon shaped thing between the two shiny pulleys secured by a plate and screw? It is a magnet and Thorens called it an Eddy Current Brake. You increase/decrease spacing to decrease/increase drag on the larger step pulley.

Notice the zero speed positions between speed settings on the selector in the first picture? Those are for idler rest, where the idler is held from any contact with the pulley so the rubber idler doesn't develop flat indentations.

PolkieMan

Thanks
I would think that once you got it set it would retain pretty well otherwise it would be a pain to be playing with it all the time. Also it would seem that a belt drive would be quieter.

SCompRacer wrote: »

To get the various speeds they used a step pulley the rubber idler pulley rides against. To fine tune speed, in the third picture, see that dark 3/4 moon shaped thing between the two shiny pulleys secured by a plate and screw? It is a magnet and Thorens called it an Eddy Current Brake. You increase/decrease spacing to decrease/increase drag on the larger step pulley.

Notice the zero speed positions between speed settings on the selector in the first picture? Those are for idler rest, where the idler is held from any contact with the pulley so the rubber idler doesn't develop flat indentations.

SCompRacer

PolkieMan wrote: »

Thanks
I would think that once you got it set it would retain pretty well otherwise it would be a pain to be playing with it all the time. Also it would seem that a belt drive would be quieter.

10-4 on the setting. As long as everytning else is set up proper and lubed, it will maintain proper speed.

First you have to remind yourself where the idler drive was coming from. Playing 78RPM records with stylus pressures around 10 grams required high torque, and the idler drives were pretty well optimized for that when LP's came out. With LP's and stylus forces dropping to 3 grams and even less, it would seem like we don't need all this. Now stick all that high torque in a thin wooden enclosure, and you create resonance and harmonics in the chassis. So yes, the idlers could rumble, and belt drives are quieter.

However, as I alluded to earlier, if you take care of the issues and then there isn't an arm or cartridge made you could not mount on it. Clean and lube, sometimes using better, modern lubricants. Maybe replace worn out bushings, or go aftermarket bearings/housings. The most significant thing for an idler drive is building a heavy plinth to absorb the vibrations the motors and drives can create. Layered Baltic Birch, (some like to mix in layers of MDF) and even partial layers or entirely Slate plinths are used. The plinths can weigh 60 to 80 pounds or more and if you did the rest of the table up right, they are dead, no rumble. They will plow through the most difficult musical passages with no change in speed. Dynamics and detail off the charts. If you can DIY, you save a bunch of cash.

Some believe sound quality from properly set up heavy plinth idler drives from various manufacturers (such as Garrard, Thorens, Lenco, Dual) is much better than current low or high torque belt drives and direct drives. One of them you have to hear it for yourself things.

[Deleted User]

Hello,
I've got the platter bearing looking pretty good, removed any of the very slight mars and restored the nice finish. I've located a good quality, non-detergent 20 weight electric motor oil to try. Also, Larry is sending a sample of DTE 25 for comparison. I bought a mechanic's stethoscope, pretty amazing how it lets the smallest mechanical noise become audible.
Cheers, Ken

SCompRacer

Beautiful, outstanding job Ken!

That stethoscope does an amazing job. It can provide you with instant gratification when an improvement is made, or send you back looking for another one. I went over every inch of my plinth with it. I used it to confirm placement for my air bearing arm, which was located close to the motor.

Do you recall the Rega Planar 2? The main bearing had some large clearances as I recall. Rega recommended a Hypoid EP80, basically a thick rear diff lube. The suggestion was apply two dollops, which I presumed to be two really big drips in British.

[Deleted User]

Thanks, Rich, the end cap was pretty grimy and tarnished as well as the record spindle, it was completely black. The bearing shaft had two areas that contact with the teflon sleeves and were pretty dull. The screws were tarnished and coated with something brown. It took a coupe of days of steady polishing to get the shine back. The end bearing came out nice and smooth along with the capture ring.
I like that, "Lord and Lady Dollop".
Now on to the motor rebuild!
Cheers, Ken

bikezappa

I have had one of those TT for over 30 years. It is built like a tank as they say. I cleaned the bearings and used a small amount of clock oil from a friend who rebiulds clocks about 20 years ago. The plater is certainly heavy. The speed stays dead on after about a minute of rotating.

My arm is not so good with the silver plating coming off. Don't remember the arm manufacture but the arm has ball bearings in it if I remember correctly.

I should sell it because I don't play records very much.

Classic engineering then and now.

[Deleted User]

Hello,
A bit of an update on the venerable Thorens. I've replaced the small mirror that is used to show the underside of the markings on the rim of the platter. The original mirror had lost most of its back coating and didn't look very good. I also replaced the four threaded 5mm rods that make up the basis of the turntable's suspension. I disassembled the speed change mechanism and the variable speed adjustment linkage and cleaned and polished everything. The motor housing and mounting bracket got cleaned up, as well. Rather than try a reuse the original rubber bushing and spring for suspension I'm suggesting that a Sorbothane half-ball could be threaded on the adjustment rods and provide better isolation and vibration damping.
Cheers, Ken

bikezappa

Nice detailed work. You can do a restoration on mine.

I have the Rek-O-Kut arm on my Thorens that has seen better days.

[Deleted User]

This is a photo of the speed change mechanism showing the drum attached with a metal band to the speed selector. This drum rotates a cam which raises and lowers the idler wheel assembly and switches off the motor between the speeds. I think it really shows the music box heritage of the Thorens company before they began making turntables. There's mention of a musical toilet paper dispenser that they made being involved in a patent dispute. They also made cigarette lighters similar to Zippos.

[Deleted User]

Here's a shot I'd taken after cleaning but before putting everything back together. I know it looks a little pretentious with the patent sheets, but I like fooling with tabletop photos.

TNHNDYMAN

When you have the skill set you do, it's not pretentious.

schwarcw

Looks great Ken! Keep up the good work. This is an exciting restoration.

PolkieMan

Good work. Interesting project one in which I think I could take a liking to. Isn't it nice how we can take as many pictures as we need when doing something like this for future reference.

[Deleted User]

Thanks for the kind words, I've enjoyed taking audio gear apart and (hopefully) getting it back together so it works. It's nice having an appreciative intelligent audience!

SCompRacer

A most exemplary display of passion and ability. Highest marks to you Ken.

[Deleted User]

Hello,
I believe the Thorens is complete, Shure cartridge installed and measurements made with the Ortofon 3000 analyzer finalized. Then a period of time listening to the combination, getting used to how the cuing mechanism works.
Enjoy, Ken

chumlie

Great job. Looks brand new.