OMA on Belt Drive: the 1953 Components Corporation Professional Model 70 

Excellent explanation of the theory of belt drive technology. 👍🏻🙏

Love the denim safari suit look!

Two things in relation to this video. First, in the context of turntable history, DC motors absolutely have not been the norm. The majority of high end turntables (which have predominantly been belt driven) have used AC synchronous motors. DC has become the norm but only comparatively recently. Secondly, regarding the videos observations on belt drive. As regards the effect of stylus drag, overcoming that drag can be achieved in a number of ways. A well designed belt drive system which can generate sufficient torque can easily overcome the effects of stylus drag. However, because stylus drag is dynamic and because belts suffer from hysteresis effects (or at least they do if they are sufficiently lossy so as not to inject motor noise into the bearing/platter) such systems usually benefit from the addition of a flywheel effect to smooth out those dynamic effects. DD systems are no different in this regard. As always in engineering, there is no "perfect" solution - just the one that is the least compromised and the latter can be arrived at by a variety of routes.

I love this technical archeology.

Thanks for these videos Jonathan, they’re very informative and fun to watch. I’m working hard to one day own one or several of your pieces.

Thank you Jonathan, when I was at college I worked for a local BBC radio station. Local stations got all the old stuff the big stations discarded back then. I remember the Pickering tone arms but the turntable was a different make, if I remember correctly it was an idler drive. We still had tubes back in the late seventies and the biggest memory I have was how warm the studios were! I love that you have amassed some incredible gear, it really is a wise move as that stuff was cost does not matter engineering. It again reminds me of the old days at the BeeB. Fairly simple easy to maintain but of the highest quality. Especially on the recording side. When I first went out doing interviews we had a small Nagra portable tape player then later in the eighties we used a Sony Walkman pro. Much lighter and less intrusive for more candid interviews but I did miss the quality feel of the nagra gear but I could go out on my own with the Sony.

Excellent! I love old vintage. With your accompaniment. Just a song!

Thank you for the history, that is important to learn from.

Belt drive, direct drive, idler wheel - all of these drive systems have their pros and cons. What matter is how well-executed each system is for a given turntable project. This video clearly favors direct drive turntables, and that's expected considering that the K3 OMA turntable is a direct drive model.

Excellent, Johnathan! 🍾🍻

I have one of these. Its not called the Model 70, it's just called the "Professional". Mine came with an Ortofon RMG 309 tonearm & surprisingly (perhaps not surprisingly) worked. The power cord is brittle & the motor could use a lube but all in all sounds amazing.

Great info Johnathan you would work well in the Museum environment great, a great piece of dialogue well done look forward to more.

Actually there are at least a couple of small companies in Europe making idler drive turntables this days, Audiosilente in Italy and PTP Audio in the Netherlands. Thanks a lot for sharing collection and your OMA videos, very impressive.

Johnathan, what a great guy! I was playing around with slate and incorporating slate into CLD plinths, with Lenco TTs on an old forum, "Lenco Lovers" a surreal, almost Monty Python- esqe drama played out regarding slate, what it does, where it's from and such. Jonathan was the voice of reason! Ahhh, yes, Welsh slate, the penultimate in "lively damping" what a drama! Anyways, I can't remember that particular fellows name, or what became of him, but it's been a pleasure following your ascent into the groove! I'm still playing with my Lenco, horns and tape, rock on guy!

Only belt drive I owned for any time was an AR and a Philips. Everything after was a direct drive.

Me too (have a lenco) 😊good idlers sound a lot like reel to reel

I have a 1958-ish Rek O kut T12 H idler table. Reconditioned and sounds awesome with a Shure 323 arm and Shure SC35c cartridge at 4.7 grams.

Average price of a car in 1953 was 4000 usd….just saying.

This is why I have a Lenco🙂

Thanks for your video. In my world, direct drive turntables such as the SL-1200 is what allowed DJing to happen. Belt drive turntables just didn't cut it. They were too imprecise. Not only did we need speed stability and precision to mix music seamlessly, but also adequate torque to scratch. DJs refused to let go of the SL-1200 and vinyl and DJing continued well into 2007 at the height of the CD format. I was buying vinyl well into 2010, but slowly switched to digital as our industry was slowly changing. With the decline of vinyl in clubs, also good sound quality went away. Vinyl sounded captivating, full and lively. All that was replaced with harsh, overcompressed and poorly mastered digital music. I wished we could turn back the clock and stayed with vinyl.

I have a professional junior by Components corporation, it doesn’t have a ground wire so Iv never used it

I enjoyed your video on turntables interesting, on this episode on belt drive it is interesting to know that you mention the problem of belt drive when tracking a groove, where there is a speed change when a difficult passage arise. This IMO is not true it's the opposite which happens on any Direct Drive turntables. I own 11 turntables, which consist of Belt Drive, Idler Drive and Direct Drive. By auditioning Direct Drive and a Belt Drive with a heavy plater the Kinetic energy over rides the lose in speed. The truth is an A/B comparison blind test between a Direct Drive and a Belt Drive. Where else the plater of the Direct Drive is designed to be very light for the close loop sensors to detect the drop in speed. Thus the direct drive suffer from wow and flutter on tracking loads. Speed variation, it is very accurate on dry run but not so on load. Compared to the Belt Drive with a heavy platter.

Rega and Dr Feickert belt drive turntables are actually very damn impressive. There are shit belt driven turntables and there are shit direct drive turntables like my noisy Audio Technica.

I'm not convinced by the argument you make there, about reduction in speed form the belt, yes the platter plays a part but the Motor putting the platter constantly under torque there should be no delay it's in real time. Chatter from the belt can play a part, that's why i use audio tape something that It's not elastic and having two Motors either side is beneficial allowing torque in both directions the issues is down to coging more than anything

Please explain then how a direct drive turntable with the typical four pole motor, four poles means it can compensate for speed changes 4 times per rotation, so if a 33.3 RPM times 4 poles gives a 133.2 corrections per minute, or a 2.22Hz correction frequency rate, how that compensates better than mass for a 10,000Hz transient. If that were the case then direct drive turntables would have low mass platters because they don't need the mass like a belt does? Please show us all these highly regarded direct drive turntable with ultra low mass platters! The only way you can handle a 10kHz transient is either with a servo system responsive at over 100khz or enough mass to plow through. With a quick a recovery time as possible. And with a belt it's ALWAYS there! With a DD, every 1/4 second or so, bump!

Have to disagree about the mat. Cork is NOT a good material. If the operator accidentally drops the tonearm onto a revolving platter, the stylus will catch on the cork and possibly be pulled off the shank.