2008 RMAF – – – all things analog.

I'll be there on the main floor in the Evergreen Ballroom, like last year. We are showing with Tri-Planar. We finally have a remote for the MP-1 too...

Looking forward to seeing so many friends again!

To anyone who may not know: the RMAF is the most fun audio show in the US. Very low-key, relaxed atmosphere and its cheap for the manufacturers so you will see stuff there that you will not see at CES or the like. I've been doing shows since 1989, and I have to admit that they get old, but I'm always looking forward to the RMAF because it is so fun! Al and Marjorie really put on a good show.

To start with the Triplanar is a more capable arm than the Schroder, with all due respect.

Having spent years in the service sector repairing audio gear, I don't think I would agree that just because a turntable is belt drive that that means it will have a speed variation (at least, one that is measurable). So far the turntables with the least amount of measurable speed variation have either been belt or direct drive (and in the case of the latter, the table in question is the Technics SP-10).

I would point to weak motor issues as being a common problem with belt drive machines. Its something you cannot get away with in an idler drive, which otherwise tends to be a noisier drive system as the motor has greater acoustic coupling to the platter. If you put a strong enough motor on a belt drive machine, you can get W&F specs that are below measurability. I'm not a fan of servo-controlled systems as they tend to 'hunt' for the correct speed (a common problem with direct drive and many belt systems).

So while I agree that many belt drive machines have speed weaknesses, it is not accurate to say that they **all** do.

Quiddity, take another look at my post. I merely pointed out that a lot of belt drive machines get away with using weaker motors, not that **all** of them do.

The motor I use in my machine has a lot of torque and behaves very much like a second flywheel in the table. It is the Pabst motor from 40 years ago- one of the better motors to be installed in a turntable. FWIW the l'oiseau lyre LPs sound great on it- despite being belt drive.

Doug, if you really want to get the inside story of what sounds right on an LP, I strongly recommend that you take a recording from the mics right to the finished LP. Do it with a 2-mic recording of natural instruments, like you mentioned. This is very handy for developing a reference because being at the session itself, you will know exactly what the recording is supposed to sound like.

BTW although we have sold a number of our 'model 208' turntables (http://www.atma-sphere.com/products/208.html), its not a regular production thing for us by any means nor have we any intention of making it so. It just seemed an obvious update path for the original machine.

Quiddity, your 2-watt figure regarding the Empire motor is incorrect- by a factor of 10. At lock-up, the motor draws 0.24Amps, that's 28 watts.

If you turn the motor on for just an instant and then try to stop it by grabbing the motor shaft with your fingers, you stand a good chance of the motor spindle cutting through your skin. You can turn the turntable on while holding the platter so it won't move, then turn the unit off, and then release the platter- the flywheel action of the motor will set the platter spinning.

Obviously it needs no help getting the platter up to speed or keeping it on speed, regardless of the music or tracking weight imposed. The speed stability of Empire turntables has long been one of the best in the business. That is one of the things that made them such a good candidate for update.

I can point to one thing that no-one seems to be talking about here. If you have a servo system controlling the motor speed, then you will experience a phenomena known as 'hunting'. This is where the servo detects that the speed is off and compensates for it. Actually, in order to do that, it has to overcompensate. So now the speed is off in the other direction, so the process repeats.

If you look at the resulting speed stability, it looks a bit like a sine wave.

Now there are ways to reduce this effect, for example by cutting the motor/platter system out of the loop, so the 'speed stability' insofar as the servo is concerned is limited to the frequency stability of the servo's inner clocks. Some servos ignore the platter and simply focus on the motor shaft rpm. Whatever the approach (and I am grossly oversimplifying this whole thing), one thing that can be counted on is that if you have a servo, its likely that it is off speed while you are listening.

Technics did an admirable job with the SP10 in that it was the first and IME the *only* DD wherein the servo issues had been developed well enough that the table actually brought home the bacon. Most of the servos I see for BD tables are inadequate, but I've not seen everything out there by any means.

Synchronous motors and eddy current motors are locked to the line frequency which is regulated by the power utility company. Power utility speed stability is very exact; their hunting cycle takes a few hours under normal circumstances. That allows for the possibility for such motors to be the most speed stable. This is why, I think, that rim drive has resurfaced after decades of being the black sheep (due to noise and lack of precision). This is also, I think, why a BD table with such motors can also exhibit the same stability.

This is a far more pronounced issue than stylus drag, however I should point out that a weak servo or weaker motor will indeed have stylus drag issues- in servicing hundreds of tables over the years, I have seen the effect be quite measurable, although not on any table with a robust drive.

One thing you will see that the SP10 has in common with other 'speed stable'/'stylus drag resistant' machines is that it also has a robust drive.

So, IMO, a machine that will truly speed stable will have a heavy platter, a robust motor and either a **very well** thought out and executed servo, or none at all. What will not be a variable is the actual drive itself- belt, DD or rim, they are all going to work if properly executed.