Wanna share some tips with me about servicing and restorations of classic analogue turntables? Don't ask to phone me, E-Mail me instead
As a starting point, you can read this file, and I urge you to buy the next 'Sound Practices Year Book', where you will find the other parts of this (long) article, with my complete history of the Thorens TD-124 & TD-125 'Gepanzert Plattenspieler'.....and, thanks to the kindness of Joe Roberts, you can also read and see the pictures of this article in this*pdf (just click over here)
Service, tweaks, weird ideas, etc
Servicing a used ‘124’ and ‘125’ (and any other vintage Thorens, in fact!) is easy, provided that the deck is complete and the motor or electronics have not been hopelessly burnt. Thorens always used good materials, so usually you need only to strip, clean, polish and lubricate the machine, checking all of its parts carefully. In the process, you will have the chance to use a whole lot of weird and potentially harmful instruments of your choice, something I always relish. Being an eye doctor, I enjoy the benefit of taking a long hard look at the idler wheels’ rubber and at the stylus tips with my biomicroscope, while to pick up turntable noise there’s nothing better then the old, dear stethoscope. I use it on turntables since I was a junior medical student (that’s 20 years ago); Lucio Cadeddu, the Editor of the famous on-line Hifi magazine ‘TNT’, one the more interesting and outspoken online audiophile magazines, has been one of the first connoisseurs to spread the word about this device and its ‘audio’ use.
The stethoscope is a revealing tool. Place it on the plinth of a running deck and you will hear, more often than not, all kind of noises, thumps, whirrs and hums. Not even a Tektronix can give you as much information on the condition of your deck, I am sure. Using the stethoscope ‘before’ and ‘after’ any procedure will not tell you if the modification has improved the musical quality of the turntable, but surely will help you to understand if you have solved a problem. I use a German-built stethoscope, of course, hoping that my Thorens will feel better for that. I also use an oscilloscope, but it’s a simple machine that I use mainly for the tracking of the hums along the signal cables.
What you will learn, using the stethoscope, is that a high-level belt-driven deck is usually far more silent than a comparable idler-wheel job, on par with excellent DDs. (I hear purists and idler-wheel junkies frown.) The ‘124’ is not a noisy table, but you will hear distinctly any ‘flat spot’ of the idler, if unluckily yours have one. You will also hear bearing trouble easily, as its resulting rumbling noise is easily detected, but it’s not easy to fix unless you decide to change the bearing, so, while you have the turntable stripped on your bench, it’s worth checking carefully the main shaft and sleeve.. This can happen also in belt-drives, but less frequently, probably because the belt pulled less strongly on the platter and thus on the main shaft than an idler. Either way, a trick worthy of a used-car salesman will help you: putting a more viscous oil in the bearing will help reducing this noise. 99% of the times a thorough cleaning and lubing will make your Thorens once again as good as new; that’s probably why I like so much using Castrol GTX3, a ‘thick’ oil, instead of other very sophisticated products. I once tried the ‘factory’ EMT oil, and it’s good if the bearing is OK, otherwise I stick to the Castrol, that’s also much, much cheaper. I’d like to try also the ‘Mobil D.T.E.’ medium-heavy oil that EMT recommended for its ‘928’ as well, but I can’t find it in Italy.
Belts and idler-wheels will have to carefully cleaned with warm water and soap, then rinsed; NEVER use turpentine, alcohol, etc, on old rubber.
Power cords and connecting (signal) cables of the decks built before 1990 are quite mediocre. They weren’t very good to begin with, so now that they’re old they are usually very bad. If you have found a stock ‘124’ in pristine condition, let it alone with the stock cables and use it for display purposes; if the deck was in a bad condition and you have to rebuild it anyway, junk the old cables go for new ones throughout, fitting a shielded power cord in the process. The plinth of an original deck has to be cleaned and then polished with plenty of beeswax and elbow grease. This effort pays off handsomely in the overall appearance of the restored/refurbished machine. And this is, more or less, what I think that ought to be allowed to do to old turntables in original condition. Let’s talk tweaks now.
For the tonearms, I’m afraid that I have some strange personal opinions. To begin with, I do not like very much SMEs. The new ones must be good, but are awfully expensive and I do not like their style; the classic 3009/3012 series is good-looking, well-engineered and perennially fashionable, but I do not believe that they are exceptional, and fixed-headshell models were a nightmare to change the cartridge. So I’ve fitted almost anything else on my several ‘125s’, from a Mayware MkIV to a Dynavector ‘505’ and Stax or a Rabco ‘SL-8’. Having developed a soft spot for Grace tonearms, I’ve tried also the ‘545’, ‘840F’ (such an elegant design!), ‘704’, 747’, finally settling as of today on a ‘707 MkII’ mounted on a special, custom-made armboard. But the Dynavector ‘505’ works wonders with a heavy plinth and a ‘124’; only, it’s quite tricky to use (no lift, etc). I understand that the ‘507’ is easier.
The design of the armboard itself is more important than most people would think, at least in the ‘125’. For a while, people designed and cut their own armboards from wood, Perspex, even glass and cheap plastics. This will give the arm a place to be bolted over, but often nothing more than that. You have to build a good armboard, otherwise the purpose of providing the deck with a 18 kilograms plinth will be negated.
This is especially true for the ‘125’, where the armboard is supported by those three metal ‘fingers’, but it’s not fixed around its perimeter. This can spoil its overall rigidity and cause some subtle resonance around the ‘free’ edges (in fact, the three sides not adjacent to the metal chassis). So I’ve experimented a bit with boards, inventing for myself a ‘code’ to identify at a glance the armboard I’m using: matt black is the original ‘factory’ board, light-grey is a reproduction in some different wood or even plastic, light green is for ‘fancy’ boards. My ‘707’ is now installed on a wafer of two slices of oak sandwiching a 3 mm foil of soft Neoprene (rubber). The three layers are glued together, and this ideally may help to kill the board’s unwanted resonance: apparently, it works. I’ve never tried an all-metal armboard, simply because it’s complicated to have someone cut them from sheet aluminium or copper (I wouldn’t use steel or iron for fear of magnetic trouble!) and I’m not sure that, at the end, a metal armboard wouldn’t ring as a bell. I plan to experiment with a glass-plastic sandwich sometimes.
One thing that I always remove from a ‘125’, if I use it for playing records in earnest, is its bottom panel. This flimsy wooden sheet is a sort of ‘dust cover’, but this creates a closed ‘box’ that I don’t like, as it might introduce an undesired ‘boominess’. I feel it’s better to get rid of it pronto, and thus get the added benefit of an easy access to the knurled knobs of the suspension, making the levelling of the unit much simpler and easier.
As the chassis/subchassis assembly of the ‘125’ is clearly uncoupled, I feel no great urge to put conical points underneath; I use rubber supports, and they work great with the stock plinth. I must say that I tried once to screw a ‘bare’ ‘125’ to a very heavy wooden plinth and the sound didn’t change a bit. I’d guess that the springs of the counterchassis insulate it so well that you don’t really need to provide a better plinth, and the belt absorbs most of the very few vibrations produced by the tiny motor of the ‘125’. I’ve tried to put some damping material (Neoprene, sponge, even hard rubber) in the springs to dampen their floating, but the results weren’t very good. At the end, this only introduced some sensitivity to acoustic feedback.
Of course, this way of thinking doesn’t apply to the ‘124’, that needs a heavy, sturdy plinth because of its powerful motor and idler-wheel drive. I like to mount a ‘124’ on a very heavy, high-density ply base, taking care to screw the chassis firmly to the plinth from underneath, using the four support screws, the ones carrying the height-adjusting nuts as retaining bolts for four nuts and washers. Between the chassis and the plinth I like to put only four grommets of hard rubber; someone would probably prefer a harder material, hardwood or maybe even metal (I never tried it). With a final mass of over 20 kilograms for a typical plinth, I feel that you do not need cones, but, if your fit a good quartet of brass points, surely they wouldn’t harm the sound a bit.
Someone fits 16" arms to the ‘124’, and special power supplies. You can, of course, but the small amount of vibration that an idler-wheel deck can produce would be amplified by such a long arm, whilst a high-grade shielded AC cord will solve 90% of the problems related to the ‘124’ and ‘125’ power supply. You have to try to believe. I stick with it and use a fairly high-mass arm for the ‘124’, like the excellent stock ‘TP-14’ or the reliable Audio Technica ‘ATP-12’, an old favourite; in the ‘125’ I use lower-mass tonearms, like the ‘707 MkII’ I mentioned before, but do not despise the ‘TP-16’ arm, a good, medium-mass design that is easy to set up and use with almost any type of cartridge. I found also the Mayware ‘MkIV’ to be well suited to the ‘125’, at least with the Denon ‘103’ I routinely use as a benchmark cartridge for the various decks I’m working on. As a footnote, I would like to say that whilst I always try to extract something more from my ‘hot-rod’ ‘125’ and ‘124’, I’ve never messed up my EMT ‘928’; like its bigger brothers, it is way too well-made and engineered to risk to spoil it with some goofy ideas and clumsy workmanship. EMTs are somewhat intimidating: probably this has something to do with the astronomic prices of their spares.
My constantly-tweaked, first-series ‘125’ (no clutch) is somehow the ‘moral flagship’ of my Thorens collection, as it’s the only Thorens normally listened to. The older decks are used in turns to keep them moving, but few of them sound as good as I’d like. As for the ‘124’, I have a ‘MkII’ that I’m perennially working on (it’s waiting a new plinth now) and another beautiful, completely original ‘124 MkII’ on display. This one is towering above the other decks in the middle of my turntable collection, and I think that it deserves this commanding position, standing proud in its original battleship-grey livery amongst the other machines of my small but dedicated collection, surrounded by lesser but always worthy Thorens and surveying from a vantage position the day-to-day work of the EMTs. I’m sure that Herr Thorens and Franz would be proud of this layout.
You can also read this excellent page of Frequently Asked Questions: