Turntable speed accuracy

Peter,

Sorry for the hyperbole.

Our own TT's speed stability did go through two periods where it drove us nuts. We heard the first problem yet no commercial strobe showed it. Paul built a custom, higher resolution strobe and we captured many hours of data to demonstrate the problem to Teres. The data helped Teres identify a problem in their motors but it took them three months of testing and measurement to confirm that the redesign/rebuild actually fixed the problem. The other problem was subtler and was addressed by our own experimentation with better belt materials and implementations.

That Aries was a touch soft on transients but much better than most BD's we've heard. In our experience many (mostly less costly) BD's are unlistenably bad due mostly to poor belt materials, as others have said.

OTOH, concluding that idler wheel/rim drive designs are inherently better than BD's would be going too far. We've had such a design in our system, made by Teres, and it was audibly inferior to our carefully worked out BD. Implementation is always critical and individual cases may trump general rules.

Dear Frogman: We have to take care about. Unfortunately no one of us have control over the recording proccess where happen " terrible " things that " disturb " ( for say the least ) not only what you are pointed out but the " original " essence of the music.

We can't restore what already were degraded on that recording proccess but at least we can take care that that degradation be the lowest one and certainly the overall TT speed subject is vita. As I posted:

+++++++++ A TT exist because the LP needs to spin for we can listen it and has to spin always at 33.1/3rpm or 45rpm : period. " +++++ NO excuses here.

Regards and enjoy the music,
R.

Dear Dougdeacon: ++++ " concluding that idler wheel/rim drive designs are inherently better than BD's would be going too far. We've had such a design in our system, made by Teres, and it was audibly inferior to our carefully worked out BD. Implementation is always critical and individual cases may trump general rules. " +++++

what do you mean with this? that Paul and you listened to two TTs bis a bis with similar tonearm/cartridges at the same sessions/comparisons?

I know both of you and I have no doubt on what you posted it is only for I can understand how that comparison was made.

In the other side, implementation as you said is critical on any audio device design or on tests as the one you mentioned.

Regards and enjoy the music,
R.

Doug, what was the nature of the Teres fix? Did they increase sampling or resolution of regulation or something else?

what do you mean with this? that Paul and you listened to two TTs bis a bis with similar tonearm/cartridges at the same sessions/comparisons?

Fair question, Raul.

One TT, one tonearm, one cartridge, everything identical except the drive systems. We were comparing our tweaked BD to the (then new) Teres rim drive. Switching from one drive to the other took < 30 seconds so it was easy to compare, far easier than comparing cartridges or tonearms.

Result: we kept our BD.

FWIW, most who made the same comparison on their tables preferred the rim drive. However, those people weren't using our belt tweak because we hadn't published it yet, so their BD wasn't performing like ours. The two people to whom I provided tweaked belts also preferred the BD to the rim drive.

Implementation, implementation, implementation. :)

***

Tdaudio,
The main problem turned out to be intermittent failures in the motor brushes. Very difficult to diagnose. After months of experimentation/verification, Teres found that gold brushes eliminated the problem and performed for the long haul. Ours is still working fine, quite a few years on.

Secondarily, Teres tightened the correction threshhold of the motor controller by one order of magnitude. Our platter speed now drifts from 33.33 (45) rpm just 10% as much as it used to before the controller alters voltage to the (DC) motor.

This improvement was visible with a good strobe if you watched for some time, but not really audible to me. One would need absolute pitch sensitivity to hear it.