Wherefore Belt Drive?

I want to initiate a discussion, not a flame war. I have a theory about how belt drive became the de facto standard for audiophile turntables, and your responses, corrections, comments, or confirmations would be most welcome.

According to Linn's history, it was founder Ivor Tiefenbrun demonstrating his Linn turntables in the early '70s that created a new paradigm in LP playback. Until Linn, conventional wisdom held that as long as the platter spun consistently at 33.33 rpm, it was the tonearm, cartridge, pre-amp, and the rest of the signal chain that made the real difference on sound quality. Linn demonstrated that the actual turntable--the device spinning the platters--had a profound effect on the sound of everything that emanated therefrom.

So what did Tiefenbrun's design entail? Chiefly, a suspended design and a belt drive. A suspended design requires belt drive. You don't suspend a direct drive or idler-drive turntable design because then you'd have to suspend the motor, one of the things you're trying to isolate the playback system from. Besides, motors are heavy and escalate the challenges to a suspended design.

Once the audiophile community accepted Tiefenbrun's premises, belt drive became cemented in its collective conscience as the only legitimate way to make the platter spin.

But wait! What if it wasn't the belt drive per se that made his TTs sound better, what if it was the suspension itself, and that the same effect could be achieved by other means, applied to other drive methods?

Turntables present a paradox wrapped in an enigma wrapped in a quandary. You must make a platter spin at precisely 33-1/3 RPM while a microphonic device (cartridge) transmits only the modulations in the groove of the LP. Spinning a platter requires a motor. Extracting the sound from a record requires a microphonic cartridge, but the cartridge must not also transmit any of the motor noise or the vibrations and ambient noise in the room! Both the motor and the sound emitted by the speakers can be picked up by the cartridge, muddying the sound.

Back in the early '70s, there were no real audio racks, no isolation devices, no Black Diamond Racing cones, no sorbothane. Noise and vibration control was unknown and unrecognized. Therefore, a suspended-design Linn, plopped down on the standard walnut veneer-over-MDF shelf of the day, as a matter of course was going to sound cleaner and more musical than any turntable that didn't take vibration control into consideration, be it idler or direct drive, which is to say, all of them. But that doesn't mean the other aspects of non-belt designs were fundamentally flawed.

I postulate that the superior sound of the Linns in the '70s was mistakenly attributed to the belt drive, when in fact it was the suspended design's isolation from feedback and vibration that accounted for the better sound.

Read the posts on this forum from the direct drive and idler drive enthusiasts. DD enthusiasts invariably say that proper platforming is crucial to realizing the potential of a Technics SL12x0 series or Denon 500M. They usually recommend spiking or coning the TT directly into a thick slab of maple or butcher block supported by shock-absorbing, isolating footers underneath the slab.

Read the posts of the idler-drive enthusiasts for pro-level Garrards, Rek-o-kuts, and Lencos, and they invariably say that a handmade aftermarket plinth is essential to realizing the turntable's potential.

The suspended design protects the turntable playback from in-room vibrations and feedback, and reduces introduction of motor noise into the playback chain. But a direct-drive or idler-drive turntable can be isolated too. A good direct drive motor, although connected directly to the turntable spindle, doesn't make much noise at all, and with a 4+ lb. platter, doesn't really have to correct the speed at 4K to 6K times per second. KABUSA has the oscilloscope photos to prove it.

Belt drives have their downsides as well. The biggies: vagaries of belt tension and friction make it difficult to dial in a precise speed; it takes awhile to spin up to speed, which ultimately depends on the flywheel effect of a heavy platter; and the vertically-oriented bearing is being pulled sideways by the belt. The only design I know of that takes this last factor into account is Well-Tempered, which is rarely mentioned on this forum. Also, the shock absorbing aspects of belt drive (at least on lower-end models with lighter platters) reduce the impact of transients and recess the midrange slightly, adding to the illusion of image depth, but actually compromising the natural presentation of the midrange.

So what I'm asking here is, have direct drive and idler drive turntables gotten a bum rap for the wrong reasons? Have they been marginalized and even scorned when in fact, they are equally legitimate drive methodologies that simply needed their own solutions for vibration isolation to bring out their potential?
I agree with much of your thesis, but with some exceptions:
(1) The Linn was not the first popular suspended tt. The AR tt preceded the Linn by at least 10-20 years in the US market and was of course recognized as a highly cost-effective solution.
(2) By the early 1970s, idler drives were already in the minority. In fact, in the US market, there was mainly the TD124 among high-end pretenders. But around that time the TD124 was superceded by the TD125. Garrards were regarded as decent but not spectacular, and Lenco was never a big factor in the US version of the high end, either. The mainstream paradigm into the 80's was direct drive. Perhaps you could say that the Linn design re-awakened an awareness of the possible benefits of a suspension.
(3) In my more cynical moments, I've considered the possibility that tt manufacturers aided by the audio press discovered a way to sell us all new tt's in the early to late 80's, by fostering the notion that belt drives per se were inherently superior to direct (and only incidentally idler) drives. One could say that the reverse shift (back to direct drive, anyway) is being promoted now, altho my own ears tell me that there is something to it, at least with regard to idler drives.
Lewm is correct (AR predating Linn) but guess what? I owned a Rek-O-Kut suspended chassis belt drive table before AR was even born!!

And the main advantage of cheap, (ie not Thorens) idler drives was they had the "muscle" to operate changer mechanisms.

And the main drawback of DD's of the time (compared to BD, not ID) was crappy construction (ie sloppy bearings, noisy motors) It's comparatively easy to make an inexpensive, but decent sounding BD TT (like the AR.)

Flash FWD: We can pretty much abandon the sprung chassis now because all MC and a lot of MM cartridges track at twice the VTF of the old Shures, and as Johnny pointed out, we now have sorbothane and various hi-tech damping devices using air and/or silicon, and even sophisticated platforms, racks, and wall shelves. This allows the entire TT, including motor/arm board to be "shock mounted" opening the way to highly advanced DD and ID designs. Has anyone seen the new Goldmund DD Reference? It'll be over $200K including a Goldmund Factory Team to set it up at your mansion/palace/oilfield? (shades of Lloyd Walker ;--)

I don't know about ID TT's, but DD is definitely coming back in some very refined designs. I've had my Goldmund Studietto for 17 years. Three years ago, I got the 'brilliant' idea to remove the springs and replace them with sorbothane pucks. What an improvement in bass, dynamics, and QUIET! And so much easier to use too -- no more bouncing platters! So I'm now looking forward to another 17 years ;-)
What about the old Dual idler drives? They were suspended.
Rwwear -- do you mean the Dual changers, or the decks? I don't know much about the old Dual/Thorens/EMT decks. And I can't remember if my old Dual changers had some spring in them somewhere or not.

05-14-07: Lewm
(1) The AR tt preceded the Linn by at least 10-20 years in the US market and was of course recognized as a highly cost-effective solution.
I knew about the AR TT, but it mostly had a cult following among budget purists and had little influence on the mainstream. It was Tiefenbrun who popularized the suspended BD design through evangelism: He literally toured the high end hi-fi shops of the '70s and performed A-B comparisons between his 'tables and whatever was the store's favorite. As I was saying, that era pre-dated most of the vibration and acoustic isolation tweaks and devices we have today, so--on an unisolated platform--a suspended design would have sounded cleaner and quieter than just about anything else, and I think the belt drive got too much of the credit.

(2) By the early 1970s, idler drives were already in the minority.
For single-play turntables, yes, but for changers, no. BSR and Garrard probably sold more TTs during that era than the rest of the companies combined. People also seem to forget that B.I.C. introduced a popular-priced belt drive line, but it lost out to the Japanese DDs for a number of reasons. I think the $200-and-up DDs of the '70s simply sounded better. I have a B.I.C. 912 at home and the Technics obliterates it.
(3) In my more cynical moments, I've considered the possibility that tt manufacturers aided by the audio press discovered a way to sell us all new tt's in the early to late 80's, by fostering the notion that belt drives per se were inherently superior to direct (and only incidentally idler) drives.
I suspect this is possible too, and it would be a way to succeed in a David/Goliath situation where the Japanese DD mfrs were the Goliaths and the small DD companies (Linn, Rega, etc.) were the cottage industry Davids. Belt drive lends itself well to cottage industry TTs. The boo-teek segment set themselves up as the One True Faith and vilified DD as the mass-market turntable for the Great Unwashed.
Just for the record, regarding points (1) and (2), I was speaking strictly from an audiophile point of view. Among audiophiles, the AR tt was a BIG seller, even to buyers with big bucks (at least that's how I remember it), and among audiophiles, BSR and Garrard changers that may have used idler drive (my parents had one) were not in the picture, just because they were thought of as "record changers", as opposed to serious record players.

For what it's worth, I recently replaced the sorbothane pucks in the elephant feet of my VPI TNT III with 1" x 1.75" maple cylinders. This produces a livelier & more detailed presentation with improved bass control. The unit sits on a sandbox base.
Both the Dual changers and the decks had a springy suspension.

05-14-07: Lewm
Just for the record, regarding points (1) and (2), I was speaking strictly from an audiophile point of view. Among audiophiles, the AR tt was a BIG seller, even to buyers with big bucks (at least that's how I remember it), and among audiophiles, BSR and Garrard changers that may have used idler drive (my parents had one) were not in the picture, just because they were thought of as "record changers", as opposed to serious record players.
No one's wrong here; it's just how we remember things based on where we were standing at the time. Linn didn't invent that design; I merely maintain that Tiefenbrun popularized it, and further hypothesize that the belt drive got too much of the credit, and the servo and motor-to-platter connection on the DDs got too much of the blame for the differences in the way the two designs sounded at the time with no help from other vibration control measures.

And for the Duals, yes, they were spring-suspended into their plinths, but as I remember, the springs were pretty stiff and probably didn't isolate a whole lot. I remember the Philips, AR, and Thorens suspended designs to be very softly sprung--jiggly, if you will--by comparison.

Do I remember correctly?
Curious where we might be had someone like Ivor Tiefenbrun not looked at the whole kit at the time and rightfully focused people to hear for themselves that the TT was making the biggest difference. The paradigm caused tremendous change. Linn also recognized the problem with AC driven motor speed and came to market with a correction, the Lingo power supply in 1991. Today many folks use power conditioners on their whole front end. Could the beginnings of that be credited back to Ivor? Who else was using outboard power conditioners in Hifi?

Happy Listening!
I believe the AR turntable was nothing like a cult machine...far from it. You could buy it at the day's equivalent of Best Buy. I think it profoundly influenced tt design. That it was cheap was a good thing...so far from the expensive, esoteric tables of today--today when, if anything, the LP itself has become a cult thing.
Basically Ivor was in with some machining concern and believed he could build his own mousetrap. Was it a better mouse catcher? Who knows, but the man had a knack for marketing that took into consideration the neurotic nature of audiophiles. Didn't he once swear he would have nothing to do with the dreaded digital?
He was also into the source being the most important. But if he really felt that way, why didn't he build phono cartridges?
Johnnyb53, I agree with you; the stock suspension on my AR table was like a trampoline. The saving grace was that the tonearm base, platter bearing, (and probably the motor; not a good thing but a necessary thing) were all firmly in synch.
Pbb, Your correct, Castle Precision Engineering Was his father's company. With an influence in industrial design, some engineering classes at Glasgow's Strathclyde, and a love for music and musical reproduction he made the Linn Sondek LP12 (sound-deck) because he was so dissatisfied with the TT's that he could go out and buy at the time. Not a bad start. It is about the whole package though, and nobody at the time had the whole package, so Ivor filled the need.
Most of us accomplish very little in life and even fewer make a real paradigm shift. Funny how easy some folks find it to criticize when they have done nothing and show nothing for the rest of us to now critique in retrospect. There are a lot of great TT, IMHO Linn is easily one of them. Besides, what Hifi, or for that matter, any other product, do you know of that can still be purchased and upgraded (improved) by a dealer since 1972? There are a few, I’m listening…

Happy Listening!

05-15-07: Inpepinnovations
He was also into the source being the most important. But if he really felt that way, why didn't he build phono cartridges?
Because Ivor's point was precisely that the cartridge is *not* the source, the turntable is, and if the turntable doesn't rotate consistently and keep the platter isolated from feedback and vibration, a good cartridge simply transmits that noise with the music.

I suspect he didn't offer cartridges at first because he didn't want to muddy the waters. There were already plenty of good cartridges; his point was that they were *too* sensitive relative to the high noise level generated by the turntables of the day.
Johnnyb53, good point, except that you mean 'the source of noise or distortion (speed variation being distortion producing)'. BTW, I agree with your contention that the isolating suspension probably had more to do with the improve sound than the belt. However, using a belt does help also in isolating the stylus from outside vibrations, at least from the motor itself.
Salut, Bob
Apologies for the ramble, some thoughts ...

Belt drive was an opportunity for the industry to make more money for less, and it was already successful before Linn.

The suspended chassis belt drive is not the secret of the LP12's success, otherwise Thorens would still be a major force in this market.

One of the best regarded tables in the early 70s was the Thorens TD125. Let's say you were quite well off at the time and had one of these. The latest gear from Japan was replacing belt drive with direct drive, so you might upgrade the Thorens for a top of the range DD. You might then feel it wasn't as good, and decide to look at the subject more closely, even to take your old turntable and start to tweak it for improved sound ...........

The Linn empire is built on the single point bearing, the rest of the LP12 is no different to several of it's contemporaries.

The bearing is where the magic is, that's why they were so keen to patent it.

Good marketing too, the dealer training was especially effective. :)

As an owner of a multitude of tables over the past 30 years; I have owned both belt and DD TT's (only one BSR Idler... as a kid in school before I got my first real "system" at 17) and I have also built four TT's myself (see current one here. http://www.vinylengine.com/phpBB2/album_page.php?pic_id=4196 And Here...
http://www.vinylengine.com/phpBB2/album_page.php?pic_id=4195). I can honestly say that I have loved the sound of my belt drives above the Technics SP-15, Teac TN-400, Denons, Kenwoods and others. The things I have learned in building my own turntables, arms & cartridges is that these things make the most difference: Mass, the more there is the harder it is to move. If you make it out of multiple different shaped pieces of different materials that resonate at different frequencies. Isolate the motor as far from the rest of the TT as possible. Don't use a belt made of rubber just because it's common to see them. We were listening to my current TT the other night and sustained piano notes sounded like they were ever-so-slightly wavering. I stopped the TT (SAMA Motor, VPI TNT Platter, & SDS) and replaced the belt with a knotted piece of upholsterer's thread and my lead-eared partner (bless his heart) asked if I turned up the volume! The cat even turned and stared at the Martin-Logan CLSIIZ's head moving back and forth watching the movement in the recording. It was like I had thrown another $2500 at the phono cartridge. And finally; a fine bearing with smooth surfaces and oils. Lots of different oils. Have Fun No Matter Your Drive Choice!

I'd like to know how you got it right with "thread drive" on the VPI. I've tried this with my VPI TNT III w/flywheel & pulleys, using dental floss as well as several kinds of thread. There is an improvement in focus and energy (and apparent volume), but instrument body suffers & a glassy shimmer on the piano tells me it's not speed-stable. The string slips unless it's really tight, and with the string pulled tight the knots ping like table tennis as they circulate. Calling Mr. Wizard!!
Cabeau, what's your favorite oil(s)? I've been using the vdH zirconium oxide stuff in my Goldmund DD and I *think* it's lowered the noise floor a lot. . . . . . . .
I withdraw my criticism of thread drive on the VPI TNT and come into agreement with Cabeau that thread drive improves upon rubber belt drive on this TT. For the thread to obtain proper grip & for the knots to run quietly, I had to remove the three-pulley system surrounding the platter. To obtain grip a thread needs to capture a fair amount of the circumference of a pulley, and this was not possible with VPI's old three-pulley system. But the big pulley on the flywheel between the motor & and the platter is a perfect transfer point for separate threads to platter and motor.

This TT has the original non-inverted bearing. The three-pulley system was designed by VPI to center the TT bearing & prevent bearing wobble, and secondarily, to minimize belt stretch by reducing the length of the belt between platter and motor. But clearly the benefits of thread drive offset any advantages of the original design. Also, any advantages the rubber belts might have had in preventing transmission of motor vibration through the drive system are moot.
Anyone experiment with waxing thread belts with beeswax? It seems lik it would improve traction. Not sure how it would effect vibration transference.
I wonder if it would be possible to design a self-contained wind up mechanical mechanism that used an electic motor to wind up the "spring" between plays and then was completely off during playback. Such a mechanical mechanism would be free of electrical anomalies and could be very quiet with precision gear reduction etc. The "escape" would be of the highest precision and noise would be below detectability. Perhaps the drive itself would be a fluid coupled as in an automatic transmission. Just a thought. Expensive as hell for sure. But rid of those dang electric motors and the force would be nearly constant on the platter, tapering off a bit toward the end of the side.
Stevecham, that would be an updated version of the crank/spring mechanism in the old Victrolas.
Magnetic drive: Magnetic bearings and (more germane to this thread) magnetic drives are seeing serious attention given by TT designers. I expect that the state of the art will keep advancing (more powerful magnets, higher platter mass, optimized platter materials for vibration control, etc.) and trickle down will cause this technology to be a strong rival to belts and DD and ID. I wonder about wobble and speed stability but with enough mass, etc., there should be reducible solutions. Perhaps, this can be coupled figuratively or literally to magnetically or air-flow suspended unipivot or linear tonearms for total isolation and otherwise high peformance. I would like to see wow and flutter measurements of magnetic-drive tables--although I would expect that current measurement techniques will initially miss the signature W&F characteristics of this type of technology, just like conventinal distortion measurements initially missed the signature distortions of CD players.