The necessity for absolute tt speed control

[Lagonda]

I can't speak about other similar devices but the Road Runner is extremely accurate. I've checked the readings against a digital tach and it's spot on and with more resolution. They're in daily use with all the AS tables.

david

And also a great tool for setting speed, even if you don’t want to use constant feedback during playback. I normally start my compressor and let the TT spin during amplifier warmup time. That way the air system, belt and TT motor reaches a stable temperature before playback, finally i connect the controller with the Roadrunner dropping the needle( for proper needle drag) mid LP, let the RR set the speed at 33,333 rpm and disconnect it again. The speed during playback will consistently move from 33,330 rpm in the start of the record to 33.336 rpm in the end of the record with my SME 3012R arm, and less deviation with my LT arm. And no i have never claimed i am normal !

 

[Lagonda]

An update on my Studer A80 motor TT project:
The good news is that it should be no problem running it with the AS 2000 controller, it likes 110-115V 60Hz.The capacitors used in the Studer A80 machines are 8,0 but they only use 25W with that load. My special motor with the heavy flywheel seems to have a consumption closer to 35-37 W at 33,3 rpm and the 6,0 capacitor is probably better suited. It looks like shit in the wooden box i made, even ended up adding some extra holes for ventilation as the motor got to hot for my taste. That will all improve with a metal box, and the birds can have the wooden one to live in. It looks like a bird feeder now: Maybe is can attract some hummingbirds, that the only way i’m getting a Colibri this summer

 

[microstrip]

Sometimes helping people in WBF gets a reward! Looking for information for the Lagonda Studer A80 motor TT project I found a mint Papst AS2000 / AirForce Zero motor for sale. It was just delivered at my door this morning ... The damn thing is really big and turns smoothly!

 

[Lagonda]

Sometimes helping people in WBF gets a reward! Looking for information for the Lagonda Studer A80 motor TT project I found a mint Papst AS2000 / AirForce Zero motor for sale. It was just delivered at my door this morning ... The damn thing is really big and turns smoothly!

View attachment 67281

Congratulations Francisco the Forsell is going to play bass and natural details at a whole new level

 

[spiritofmusic]

Likely to pass on the Condor/SOTA motor upgrade for my tt. There are some issues with complexities of offset install in housing. And I remain unconvinced I want any DSP feedback loop from speed tach. My tt designer tried for over 12 months to finesse a feedback loop system that didn't deteriorate the sound, and he failed.

I'm likely to follow up tentative plans for an all-analog zero-feedback motor/speed controller, combined with an audiophile-quality...and silent...air compressor for my LT arm.

I've already spent in excess of £5k for Stacore Advanced and 50kg slate stand, and the same amount on three LPSs for my tt and Straingauge energiser.

A similar amount on bespoke motor that promises stable drift-free speed and highest quality air flow to my tonearm is totally in keeping.

 

[spiritofmusic]

A guy whom I've become friendly with in the US, and who runs my Salvation tt setup, has just installed a Condor/SOTA upgraded motor. He's gone ahead with a custom Delrin rim wheel to replicate what we currently both use.

Our stock motors are not the height of sophistication, with an easily measured speed fluctuation, especially linked to changes in ambient temperature and humidity.

The new Condor motor is nailing 33.33 +/- 0.01. And the SQ benefits are easily audible in primarily greater bass articulation/definition, more solid imaging, less noise and haze. Very few if any downsides, he is enquiring about those, more operational quibbles than SQ.

There seems to be a tad less euphonic colouration, meaning some material seems "smaller" and less exciting. But this is the exception rather than the rule.

And scope for even greater SQ uptick with move to dedicated LPS/fuse/power cord, and vibration isolation under the motor.

 

[edwyun]

I, and others, have experienced the same with the SOTA condor/roadrunner package on our VPIs. And previously with the Phoenx eagle/roadrunner package.

 

[spiritofmusic]

Edwuyn, the dilemma/risk was adding this to a rim drive tt, and incorporating Roadrunner feedback where stock motor is designed to be 100% non feedback.

 

[spiritofmusic]

Further feedback from my Condor/RR using mate...tonality and image stability rock solid and spot on.
He has a favourite track on LP with three female singers in a mini choir. Up to now, stock motor has had a tendency for the singers to waver in position and focus, no two days sounding alike. Tone variable too. He's now achieving a more predictable, replicable sound day on day, that is adding to the illusion of reality.
I suspect I may be a tad less sensitive to the "image lock" achieved, but should notice this more natural consistent tonality, as tone and timbre are the things I've come most to appreciate, and be sensitive to, as a combined result of my room/system optimisation comes together, and my greater exposure (pre-Covid) to live unamplified.

 

[spiritofmusic]

Just installed the SOTA Roadrunner tt speed tach. No go to start until goodfellow Lagonda here suggest I flip the magnet over.

Maybe I should be embarrassed, but it appears my tt is 1% inaccurate, varying 33.33 +/- 0.33. It's often around 33.25-33.40, but rises and drops further on occasion.

Interesting to see stylus drag in evidence.

Do I hear the sound come into clear focus when RR hits 33.32-33.34? No.

Do I perceive pitch issues at 33.00 or 33.66? No.

And thus, I'm no closer to an answer to the question posed in the title of this thread.

One riddle. An LP that normally sounds flat and uninviting (Free "Tons Of Sobs" 90s reissue), was pretty vital just now. Maybe the effort that I took to set speed via RR is being rewarded over my previous reliance on strobe. And so I've set a more accurate mean speed, fluctuations less of a perceivable issue for me personally.

 

[spiritofmusic]

Interesting, just finished playing some classical vinyl and speed started stopping drifting, 33.333 +/- 0.100, putting speed closer to 0.3% variation/drift.

From now on, I'm gonna run my tt motor for longer prior to playing vinyl, maybe start the day with cd. To see if a warmed up motor makes a practical difference.

 

[Lagonda]

Interesting, just finished playing some classical vinyl and speed started stopping drifting, 33.333 +/- 0.100, putting speed closer to 0.3% variation/drift.

From now on, I'm gonna run my tt motor for longer prior to playing vinyl, maybe start the day with cd. To see if a warmed up motor makes a practical difference.

Its not just the motor Marc, its also the bearing and rubber surfaces warming up. I start my TT at least an hour before playing time, together with my amps and preamps

 

[spiritofmusic]

Sure.
It will be interesting to see if there is some pattern to ascertain here.
Early evidence suggests I'll be ordering the SOTA Condor/Eclipse.

 

[edwyun]

After warmup, the Eagle/RR (and now Condor/RR) are stable well over a minute...

 

[spiritofmusic]

And what was speed accuracy before Condor?

 

[Lagonda]

After warmup, the Eagle/RR (and now Condor/RR) are stable well over a minute...

Is that with or without feedback ?

 

[edwyun]

Just ran these. This the SOTA condor motor with no feedback (e.g., RR disconnected) on my VPI Prime:

 

[edwyun]

And this is the SOTA condor motor with feedback loop (e.g., RR connected) and is consistent with the prior 0.0492% reading which was also with feedback loop.

 

[microstrip]

Interesting. Can you show the wow and flutter measurements in log scale? They are meaningless in linear scale.

 

[spiritofmusic]

Edwuyn, does Condor/Eclipse bring anything other than straight speed to proceedings? I mean, less noise/vibrations, advantages re torque?

I can't be sure, but even though I'm purely observing the speed of my current motor with newly installed RR, the fact I can be more accurate setting and adjusting speed seems already to be bringing advantages to the fore.

Greater bass certitude...rhythmic lines and bass harmonics becoming more assertive and unmistakable. Piano in particular has greater articulation. Critically, massed instruments are maintaining group density, but individual lines are easier to pick out.

This is the first time I'm genuinely convinced going to a new motor to nail speed accuracy and minimise drift is absolutely the right thing to do.