Thorens TD-150AB turntable and tonearm

This is an integrated arm-and-turntable unit using single-belt drive from a stepped motor pulley to an inside platter (under the main one), and having a three-point suspension similar to that in the AR turntable for isolation from acoustic feedback and floorborne vibrations. Speed change is accomplished by a two-pronged "fork" which, actuated by the speed selector knob, throws the belt from one step of the motor pulley to the other. The motor is a special synchronous type that is actually two motors in a single case. Their speed is determined by the frequency of the AC supply, so there is no speed adjustment.

The tonearm is made of tubular aluminum, with offsets at both the pickup end and the counterweight end. The latter holds the counterweight to one side of the axis of the arm, to compensate for the torsional force caused by the offset head. Stylus force is adjusted by sliding the counterweight back and forth, in conjunction with a removable calibration plate. The calibration plate rests on the rear of the arm, with its scale positioned to read the desired stylus force, and the counterweight is adjusted until the arm is in perfect balance. Removal of the calibration plate then unbalances the arm to provide the proper tracking force. This proved to be one of the most accurate force-setting systems we've seen.

The counterweight has enough range to balance any but the very lightest pickups (such as the Euphonics), which will require a small additional weight in the head. Even the heavy Ortofon pickups (footnote 1) can be accommodated without an additional counterweight, but the length of these pickups makes it difficult to install them without shorting their connecting pins to the terminals at the rear of the plug-in shell. These terminals may be bent out of the way to provide clearance.

The tonearm's height is fixed, but there is provision for adjusting the length and the vertical angle of the plug-in shell, to provide the optimum tangency and vertical tracking angle for any pickup. The base of the tonearm is fitted with a cueing device which is viscous-damped to prevent the pickup from slamming down on the record when the cueing lever is operated rapidly. There is no bias compensation provided.

Test Results
In performance tests, the turntable proved to have exceedingly low wow, flutter, and rumble—lower in fact, than the TD-124 and about on a par with the Acoustic Research turntable. Like the AR unit, the Thorens uses a low-speed drive motor, which puts whatever motor-induced rumble there is at an inaudible below-15Hz frequency (footnote 2).

The AR's natural rumble frequency is at 10Hz; the Thorens' is at 7.5Hz. Both speeds on our sample TD-150 ran about 5% fast, and were unaffected by normal pickup loads. Subjectively, this 5% inaccuracy causes a barely perceptible increase in musical tempos, and raises the pitch of the music by a shade less than one semitone. There is enough torque to use one-wipe record cleaners like the Watts/ELPA "Preener," and the use of a "Dust Bug" reduces the speed in outer grooves by about 2%. (The Dust Bug has virtually no slowing effect when working in inner grooves.)

Hum radiation was extremely low, permitting even such hum-sensitive pickups as the Ortofon SPU and SPE to be used without hum problems. The vibration suspension was judged to be only fairly effective. It was better than none at all, but even a typically bouncy floor could cause the pickup to skip grooves with every heavy footstep.

The tonearm pivots in our sample were badly out of adjustment. There was a considerable amount of free play in them and, as a result, the arm was leaning over to one side and tilting the head shell by more than 5°. We were able to adjust these to get rid of most of the play without causing an excessive increase of binding in the pivots, but we were not able to eliminate all the tilt from the head. Fortunately, Thorens supplies a number of thin spacer washers in their pickup-mounting hardware kit, so we were able to shim up one side of the head until it was parallel to the record.

There is nothing intrinsically wrong with these cone-type pivots; they just don't seem to lend themselves to mass production. Each must be individually adjusted to within quite critical tolerances, and few production-line workers will take the trouble to do this. The result is usually a degree of sample-to-sample variability that makes the purchase of a properly-adjusted one a case of sheer pot luck.

Performance
With the pickup leveled and the tonearm pivots adjusted to minimize both play and friction, the arm behaved as any good, moderate-mass arm should. There was no evidence of problems due to pivot rattles, but we did find that the sound from the pickups we used in it was not quite as clean at a given tracking force as in, say, the SME arm. This may have been due to the lack of bias compensation on the Thorens arm, or to its moderately high vertical friction, which was measured at slightly over ½ gram. Loosening of the pivots did not significantly reduce the friction.

Some care is needed when operating the tone cueing lever. The three-point anti-vibration suspension that allows the base to vibrate without disturbing the pickup also makes it easy to jiggle the whole playing system by rough handling of the lift lever.

Conclusion
The TD-150AB, then, resembles the Acoustic Research turntable both in basic design and performance, although the AR is considerably more accurate in running speed and has shown little variability in tonearm adjustment from sample to sample. These two factors alone would tend to swing the choice toward the AR and the fact that the TD-150AB costs about $20 more would seem to confirm the choice.

The TD-150's speed inaccuracy is due to a simple case of oversized motor pulleys, and should be easily remediable in future production models (if it hasn't been corrected already—we tested an early sample). With this problem ironed out, the TD-150 would make an ideal turntable for the perfectionist to use with the tonearm of his choice, and we hope it will be released in an armless version for that purpose. At present, it is available only with its integral arm, although the instruction manual refers to a model TD-150B that comes without an arm, so perhaps a basic table unit is in ELPA's future plans.


Footnote 1: For the benefit of those readers who are becoming confused by the strange spellings used in some other magazines, we point out that "f" is correct, "ph" is not.

Footnote 2: Although inaudible, it is possible for subsonic rumble to cause problems by overdriving the power amp or loudspeaker at this subsonic frequency, where power-handling ability is likely to be extremely limited. Normally, the rumble from the AR or Thorens units is well below the trouble level, but a defect in the turntable—a bent motor shaft, for instance—or an unfortunate arm-and-pickup pairing that resonates at below 10Hz could cause overloading, if in doubt, watch the loudspeaker cone (or feel It with the fingers) when playing a silent groove. If the cone vibrates continually at an inaudible frequency, you've got trouble.

COMPANY INFO
Thorens, Germany
US Distributor: American Audio & Video, A Division of JAM Industries USA, LLC
310 West Newberry Road
Bloomfield, CT 06002
(856) 596-2339
ARTICLE CONTENTS

COMMENTS
John Atkinson's picture
This Thorens was my first high-performance LP player, fitted with a Shure M75EJ phono cartridge.

John Atkinson
Technical Editor, Stereophile

Bogolu Haranath's picture

Fast forward to 2020 high performance audio ....... Wireless speakers like B&W Formation Duo ($4,000/pair) and streaming music :-) .........

Bogolu Haranath's picture

Memorias del pasado :-) ..........

jimtavegia's picture

There are still TT's that are more than these (even counting inflation) that still don't offer the performance of this Thorens or the AR, and I do wish I had kept my AR. What a foolish soul I was for selling it.

Ortofan's picture

... Thorens TD-160 and have never regretted doing so.
The tonearm on the AR was totally inferior to the one on the Thorens.

jimtavegia's picture

I bought mine for less than $100 and with the Shure Type III it sounded so good even with the phono stage in my Fisher 500TX and my Dynaco A-25's. My first entry in to audiophile land was a nice one.

Ortofan's picture

... inexpensive receiver. Also in that price range were the Marantz 2270, the Sansui Eight and maybe one or two from Sony.
How did you happen to opt for the Fisher?

jimtavegia's picture

that was used in another system with AR speakers and it had a Dual 1209 with a Pickering XV 750. The Fisher choice was based on good sound and it had 5 present push buttons for fav FM stations. WE listened to much FM back in the day. It also had my first cassette deck, a Teac 350 with it. I used an outdoor FM only Antenna from Wingard so enough signal was not an issue. The Dual's weak link to me was always the tonearms. I still have a Dual 502 with a high torque AC motor and I replace the Dual arm with a Rega RB 251 and it still sounds great years later. I may buy a new Technics 1200 this year, but will see as my recording hobby is more important to me now. I use all Tascam SD card recorders in 2496 or 24192.

Ortofan's picture

... the Dual tonearm was a weak link?
While the arm may have had a deceptively simple appearance, the performance was nevertheless quite impressive, as demonstrated in the following test report:
http://www.audio4maniacs.co.uk/article-dualcs505.html

jimtavegia's picture

That Dual arm is no match for a Rega RB251. Anyone who owned auto or semi auto heard that arm tube clank into the arm rest with little if any damping. Of course if you like the Dual arm please own one. I also owned a Dual CS5000 and the damper fluid dried up and the arm dropped quickly into the arm rest when the auto return was engaged.

I know what I heard going from the Dual arm to the Rega.

Ortofan's picture

... that had an auto-return tonearm function?
The CS5000 I have only lifts the tonearm and stops the motor at the end of a record - it does not have any mechanism to return the tonearm to the rest. This is confirmed by the information in the owner's manual.

The resonant behavior of the Rega tonearm is inferior to that of the Dual. The resonances are higher in frequency and of higher Q, such that they are more likely to be audible, as compared to the Dual. Perhaps they are adding some colorations that are perceived as preferable?

Amclaussen's picture

While Dual tonearms suffer from a very short effective length, their design and construction is MUCH better than 99% of the popular and "sexy" curved tonearms used by every Japanese turntable manufacturer back in the 70's...
The Dual tonearm is straight, lowering mass and achieving rigidity, and has quality bearings. If you have one that shows play, it is because it was heavily mishandled! Plus, the tracking force was applied by a clock type wound spring, so that it avoided the bad effects of a not getting a perfectly level turntable. My Dual CS-604 still works as new after 40 years, but is obviously not a match for my Thorens TD-160 Super... and I only use it for background music and while I have a dinner at home with guests, because I wouldn't never risk my precious Grace arm and even more precious F9E!

Amclaussen's picture

I completely agree with you: I repaired or adjusted many AR turntables when we went from 50 Hz AC to the 60 Hz used worldwide back in the 70's... It required to cut the bigger motor pulleys in a lathe to compensate for the faster running at 60 Hz. In my own experience, the AR turntables were of very variable quality, I'd say that for every 10 AR turntables, one or two came form AR factory "passable"... and the rest were from barely acceptable to So-So... Perhaps the very old Thorens arms were not so good, but soon they raised their quality and probably from 1972 on, the Thorens were much better than the rare "good" AR tonearms.

I bought my Thorens TD-160 Super (the "audiophile" armless versión) in Houston in 1979, and a fine expert installed a Grace 747 arm with a Grace F9E cartridge using every protractor available, and then performed several listening sessions to really get the best performance above that of the protractor dictated settings, there I learned how critical the several angles were, specially the offset and the "VTA". After perhaps 5 or 6 years, I started to perform several modifications, some very succesful, some terrible!, and elevated the basic design to stratospheric levels. I fabricated a heavy and thick 4 layer acrylic cover laminated with the same resin used to laminate automobile windshields (hard to get!), designed and built a dedicated Power-Supply to feed the AC motor with an almost perfectly sinusoidal AC waveform, free from measurable distortion and noise, and heavily modified the original base to dampen all resonances with lead and felt pads glued with viscoelastic goo, and remade the flimsy bottom cover with a damped and thick MDF one. The two piece platter was damped too and that made a big improvement! The results rival "modern" turntables costing as much as 15 times the 1,000 US Dollars paid. It seems that I would NEVER replace it or Exchange it for any other one!. Been there, done that. Amclaussen.

jmsent's picture

It had a nice heavy platter and springy suspension. The speed issue was unfortunate, and I recall that virtually all the ones I set up ran fast as well. Given the synchronous motor, it should have been possible to get the speed near perfect, and AR certainly was able to do so on a much more cheaply made player.

Bogolu Haranath's picture

This article was first published in 1966 ........

Year 1966 in music :-) ......... .........

Frank Sinatra album 'Strangers in the Night' was released ....... made it to No.1 in Billboard chart ......
Beatles release singles 'Yellow Submarine' and 'Eleanor Rigby' .........
Rolling Stones release single 'Paint it Black' .............
The Beach Boys release single 'Good Vibrations' ...........

dial's picture

It's a shame we couldn't buy cheap NEW tonearms anymore (i.e. around 50-100 bucks), of course with detachable SME headshell. I saw some interesting ones on dj decks but not available separately, unfortunately. The arm make a huge difference, if you can adjust it properly, especially in height. It's not neccesarily an expensive investment.

Trevor_Bartram's picture

A friend had a TD150 and nice Ortofon cartridge back in 70s, I recorded many of his LPs on it. I had a home built Connoisseur turntable with SME tone arm, that didn't work well due to the way I constructed the plinth. In the early 80s I bought a CS505 with Grado FTE cartridge, I liked the way the combination sounded, I still have it but put it in storage ten years ago.

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