The necessity for absolute tt speed control

[tima]

I'm gonna agree with Lagonda here, it's not the absolute numerical speed accuracy that's most critical, it's the lack of moment to moment waver.

It's both. Stable accuracy.

This lack of cyclical swings and roundabouts is making the critical difference. And WHAT a difference! I know I'm prone to that awful audiophile malady Epiphanous Pretentiousity, but the change here is of an order of magnitude greater than any other changes, save for my room acoustics uplift (actual room move and major bass suckout solution), and isolation of tt via Stacore/correct analog setup. I would say by having these factors sorted, the uplift from minimal speed drift with the new motor is magnified.

Where I'm so happy is the dramatic turnaround on classical. The Janacek/Mládi piece I listened to the other day is transformed from a tad grey and smeared to uncluttered, hugely transparent, dynamics especially improved, timbral accuracy and air to spare. For the first time, classical music that always felt shut in and gritty via my Zus, is sounding much more independent of the spkrs, way closer to the great systems I've heard in the last few years.

It's interesting that people think they need to hear or not hear some specific thing to appreciate stable accuracy. I read it all the time: "I can't hear any difference between 33.333 rpm and 33.35 rpm, so why does it matter?" It doesn't matter until you experience the difference and you certainly don't need perfect pitch to appreciate it. The signal created at any given instance of stylus-groove interface is different when timing is correct. Everything described by the audiophile lexicon (dynamics, tonality, presence, energy, flow, spatial characteristics, etc.) is better when the signal is created consistently at 33? rpm. We don't typically think of dynamics as impacted by timing. I found the greatest improvement was in dynamic facility when switching from the Monaco 1.5 to version 2.0.

 

[spiritofmusic]

That's pretty much how it's turned out Tim. Audiophile Bill, who plays a musical instrument, says he's very much aware of pitch and timing that's off, yet me as a drummer (proving the old cliche that we're deaf or not talented enough to play a real instrument Lol) seemed blissfully unaware.
So, when the Roadrunner speed tach was installed, I listened intently...and could hear no difference as my speed was now shown to be unreliable, occasionally at 33.333, but more often drunkenly veer from 33.000 to 33.666, occasionally even worse. No matter how intently I listened out for change, my SQ seemed uniform at anything up to +/-0.5%.
Going for the SOTA motor was thus a tough sell, I was truly skeptical I would get the "benefit". Maybe this drummer has no feel for pitch.
But strong-arming from my Cali based friend who has my tt/arm and had upgraded to the SOTA had the desired effect.
And what was fascinating was that as speed settled from 33.000-33.333-33.666 (and back down and up again) with my stock motor to 33.330-33.333-33.336, sometimes 30 seconds continuously at 33.333, as the minutes went by listening to my most familiar music presented more "precisely", there was a whole scale change more holistic than other upgrades.
A feeling of calm...not muted dynamics, actually the opposite, as jump factor was highlighted because the underlying signal was so calm...emulating live music where a triangle can have maximum impact from the gentle thrum of strings.
Greater tonal discrimination...albums more than ever sound totally different from each other, greater timbral articulation...twin horns in jazz really sound different not amorphous. This timbral thing was already improved with my improved update on LT air arm, but the SOTA motor reinforces and extends this benefit. Again, getting closer to the live acoustic unamplified benchmark.
One thing I've never really had with my Zus was a feel for any proper imaging. A certain "wall of sound", tone density and immersive immediacy over more refined aspects I hear with great horns and ribbons, and on cone/dome spkrs at many multiples of the Zu price.
Well, the SOTA has both fleshed out tone and timbre while also decluttering the soundstage to present imaging that while still very holistic and not artificially spotlit and pinpointed like the worst of the pricey box spkrs I've heard, just gives more of an idea of the space and relationship in music.
These changes album to album, and even track to track within albums.
The overall effect is the proverbial Vitamin D shot to musicality, authenticity, and the proverbial removal of veils, this removal being a wholesale increase in communicativeness, the fantastic totally unexpected benefit being a classical and jazz collection that is fully engaging and not feeling constricted and obscured.
This change up there with the radical effect of the change to this room, and engaging with the magic of tube amps for the first time.

 

[tima]

And ... there it is! I'm glad you have the opportunity to experience what better timing brings to vinyl replay.

 

[Lagonda]

It's both. Stable accuracy.



It's interesting that people think they need to hear or not hear some specific thing to appreciate stable accuracy. I read it all the time: "I can't hear any difference between 33.333 rpm and 33.35 rpm, so why does it matter?" It doesn't matter until you experience the difference and you certainly don't need perfect pitch to appreciate it. The signal created at any given instance of stylus-groove interface is different when timing is correct. Everything described by the audiophile lexicon (dynamics, tonality, presence, energy, flow, spatial characteristics, etc.) is better when the signal is created consistently at 33? rpm. We don't typically think of dynamics as impacted by timing. I found the greatest improvement was in dynamic facility when switching from the Monaco 1.5 to version 2.0.

Tim, if i blindfold you and change the speed from 33,333 to 33,350 you will not hear the difference, that is about the difference between needle in groove, and out of groove. If i change your motor and controller to a lesser type, like a Hurst AC motor running at perfect 33.333 of main line power it will sound lees dynamic with a smeared treble, compared to your reference setup. There are more than one way to skin a cat, your system uses ultra fast micro adjustments on a light platter to keep speed stable. TT's like Peters Micro Seiki and the even more extreme AS 2000 use a heavy platter with a powerful stable motor to create the uninterrupted drive forward, it also evens out the power ripples that become audible with lesser motors and controllers. I have also found, that a flywheel greatly improves the sound on the belt driven TT's, the flywheel increases torque transfer and acts as a ripple buffer, absorbing the micro ripples from the motor poles during operation.

 

[spiritofmusic]

Tim, this episode has ranked alongside the "room acoustics don't really matter, do they?" preconception.
The room argument was always a hard one to judge, primarily because one can't do an A/B at all easily, and a different room is a different room, with a different system.
It was impossible for me to seperate the change of SQ for the better in a room other than mine because the system in that new room was so different from mine.
With TT speed control, this was all reversed, I could visually detect a change good or bad with the Roadrunner speed tach versus checking a strobe disc. But absolutely nothing was discernable within that +/-0.5% range. If it was discernable, it was ephemeral as speed approximated to ideal. Kinda like checking a pendulum either side of a midpoint.
I'm very much of the opinion that speed accuracy and stability is also opening up cognitive ease in listening.
When there is haze in the sound, even if its subliminal, one is trying to hear "thru" it. This is the very opposite of relaxed listening.
I can't tell you the number of times classical LP listening would lead me to infernal micro adjusting of my Zu subs settings, never to any happy outcome.
But the room change>settling on Zu subs settings w help of Revopods spkrs footers>eliminating of major bass suck out in room>nailing down TT speed control via SOTA m>eradicating preamp noise via best NOS tubes and specialist DB25 cable>PET boards eaves treatments>removing all Entreq grounding boxes and cables...has wrought fundamental change in my sound, most critically clearing all charges against my Zus as being veiled or non transparent, and totally reinvigorating my classical and jazz LP collection, that had been languishing unloved and unappreciated. Indeed I'm buying LPs in these genres at a rate way beyond anything else.

 

[Lagonda]

That's pretty much how it's turned out Tim. Audiophile Bill, who plays a musical instrument, says he's very much aware of pitch and timing that's off, yet me as a drummer (proving the old cliche that we're deaf or not talented enough to play a real instrument Lol) seemed blissfully unaware.
So, when the Roadrunner speed tach was installed, I listened intently...and could hear no difference as my speed was now shown to be unreliable, occasionally at 33.333, but more often drunkenly veer from 33.000 to 33.666, occasionally even worse. No matter how intently I listened out for change, my SQ seemed uniform at anything up to +/-0.5%.
Going for the SOTA motor was thus a tough sell, I was truly skeptical I would get the "benefit". Maybe this drummer has no feel for pitch.
But strong-arming from my Cali based friend who has my tt/arm and had upgraded to the SOTA had the desired effect.
And what was fascinating was that as speed settled from 33.000-33.333-33.666 (and back down and up again) with my stock motor to 33.330-33.333-33.336, sometimes 30 seconds continuously at 33.333, as the minutes went by listening to my most familiar music presented more "precisely", there was a whole scale change more holistic than other upgrades.
A feeling of calm...not muted dynamics, actually the opposite, as jump factor was highlighted because the underlying signal was so calm...emulating live music where a triangle can have maximum impact from the gentle thrum of strings.
Greater tonal discrimination...albums more than ever sound totally different from each other, greater timbral articulation...twin horns in jazz really sound different not amorphous. This timbral thing was already improved with my improved update on LT air arm, but the SOTA motor reinforces and extends this benefit. Again, getting closer to the live acoustic unamplified benchmark.
One thing I've never really had with my Zus was a feel for any proper imaging. A certain "wall of sound", tone density and immersive immediacy over more refined aspects I hear with great horns and ribbons, and on cone/dome spkrs at many multiples of the Zu price.
Well, the SOTA has both fleshed out tone and timbre while also decluttering the soundstage to present imaging that while still very holistic and not artificially spotlit and pinpointed like the worst of the pricey box spkrs I've heard, just gives more of an idea of the space and relationship in music.
These changes album to album, and even track to track within albums.
The overall effect is the proverbial Vitamin D shot to musicality, authenticity, and the proverbial removal of veils, this removal being a wholesale increase in communicativeness, the fantastic totally unexpected benefit being a classical and jazz collection that is fully engaging and not feeling constricted and obscured.
This change up there with the radical effect of the change to this room, and engaging with the magic of tube amps for the first time.

Marc, you truly are a excellent writer !
You too of coarse Tim !

 

[spiritofmusic]

Thanks Milan. WBF has given me many opportunities to practice Lol.

 

[Lagonda]

Tim, this episode has ranked alongside the "room acoustics don't really matter, do they?" preconception.
The room argument was always a hard one to judge, primarily because one can't do an A/B at all easily, and a different room is a different room, with a different system.
It was impossible for me to seperate the change of SQ for the better in a room other than mine because the system in that new room was so different from mine.
With TT speed control, this was all reversed, I could visually detect a change good or bad with the Roadrunner speed tach versus checking a strobe disc. But absolutely nothing was discernable within that +/-0.5% range. If it was discernable, it was ephemeral as speed approximated to ideal. Kinda like checking a pendulum either side of a midpoint.
I'm very much of the opinion that speed accuracy and stability is also opening up cognitive ease in listening.
When there is haze in the sound, even if its subliminal, one is trying to hear "thru" it. This is the very opposite of relaxed listening.
I can't tell you the number of times classical LP listening would lead me to infernal micro adjusting of my Zu subs settings, never to any happy outcome.
But the room change>settling on Zu subs settings w help of Revopods spkrs footers>eliminating of major bass suck out in room>nailing down TT speed control via SOTA m>eradicating preamp noise via best NOS tubes and specialist DB25 cable>PET boards eaves treatments...has wrought fundamental change in my sound, most critically clearing all charges against my Zus as being veiled or non transparent, and totally reinvigorating my classical and jazz LP collection, that had been languishing unloved and unappreciated. Indeed I'm buying LPs in these genres at a rate way beyond anything else.

Marc, part of the improvement you are hearing is that the dedicated BLDC motor that Bill Carlin from Phoenix Engineering chose for this project is a very stable and precise motor when used with his dedicated Condor controller. The controller software is a 3 phase customized system made while measuring all parameters of behavior during playback of this particular motor. A time consuming highly specialized task, that not many people master. It is not only better speed stability but also much smoother operation of the motor that you hear in your setup now.

 

[spiritofmusic]

Oh sure Milan, I realise it's not a strictly "apples and apples" comparison. Not "apples and oranges" either. Maybe more "green apples and red apples". Or "apple flan" and "apple pie". Whatever, deffo only apples are involved.

 

[spiritofmusic]

Interestingly, I think after my conversions to the cause on good acoustics, and now the priority of accurate and stable TT speed, I'm more aware of poorer situations regarding these. Only have to recall my old room and stock TT.
Certainly I'm alerted to substandard rooms way more than I used to/ever thought was relevant.
I heard a top of the line horns demo over a year back, it was so apparent how the room was holding things back despite the quality of the gear that day.
Would I pick up on another TT with poor speed issues? I wouldn't be so bold as to say for sure.
Not many TTs, top ones or otherwise, publish speed data. And it's not as if one regularly goes to demos w TTs
...can you imagine asking the owner of a £50k analog setup if they'd mind me plonking a Roadrunner into it, and then passing a verdict? Lol.
But knowing what I know that way greater speed accuracy has brought to my table (pun intended), an antidote to tendency to veiling, greyness, lack of jump factor, plodding one note tone and timbre...in the past I'd have blamed the rest of the system...now I might look closer to home re speed.

 

[Vienna]

Just for the record, the Roadrunner measures speed with a resolution of 1/54,000 or 0.0000185 (33 RPM) or 1/40,000 (45 RPM) using a time base accurate and stable to 2.5PPM (0.0000025) over the entire commercial temp range (-30°~+60°C). In a controlled temp environment like the typical listening room, the stability is many times better.

 

[Vienna]

it would be completely wrong though, for someone to assume that for the desired speed stability, the critical component is only the motor and the controller. In fact the bearing design, belt materials and platter’s balanced well distributed mass are of equal importantance.

For this reason for someone to address and solve speed instability issues besides the speed measurements he will need to measure vibrations and resonances in order to locate the source of the speed issue. A closed loop with speed feedback and continuous speed corrections is just a patch to cover the issue , but it’s still there, affecting the sound.

In the past I used to own a manufacturer’s reference model equipped with rim drive (two motors driving a rim drive disk) and a magnetic driven platter.
trying to correct the unstable speed and the motors resonances , Bill Carlin made for me a new drive with BLDC Anaheim motors (the same that SOTA is using) driven by a high biased class AB amplifier and equipped with the Roadrunner tacho.

The result was a way more silent operation but I was experiencing continuous speed corrections (Condor’s led was continuously blinking), while the Roadrunner tacho was displaying a speed range (33.330-33.339)

I thought that it was the drive and rim belts so I made new from EPDM, the belts improved the situation but still the speed instability was there.

Much later I discovered that the bearing, the bearing thrust and the bearing liner were made with loosely tolerances and even the platters were wobbling. The lubricant was insufficient Too.

By replacing the worn bearing with Si3N4 , fabricating new shaft, installing a sapphire thrust, installing bearing liner and balancing the platters the speed stability issue was rectified and the continuous speed corrections disappeared.

The correction of those issues and the achievement of stable accurate speed was translated undoubtedly into a better sound comparing to the earlier condition, but still that rectified tt was lacking of the sound quality that superbly designed and engineered turntables are offering.

 

[spiritofmusic]

That wasn't the TT Weights tt out of Canada? Other than my model, I don't know of any other commercially available rim drive choices from that time. Indeed, the TT W and my Trans Fi have now both ceased production, leaving just Reed.
I am fully aware my tt is not in the front rank/premier league. At £1800 when new in 2013, how could it be? However it has a killer sound in many respects, and there are a few examples of owners of highly modded Garrard 301s who decided to trade for the Salvation.
Because the tt and arm came as a complete, holistic design combination from the same designer, this was a big pull too, and I'd propose that the air LT Terminator arm is truly a fantastic product.
Over the course of upgrading the Salvation, first w Reso Pods on platter, then magnetically isolating feet and bearing, adding 150kg Stacore platform/inert slate stand, and now the SOTA Condor Eclipse Roadrunner motor setup with Farad LPS on Symposium Svelte isolation pad, I've eeked out big improvements each time.
But the SOTA change has wrought a fundamental change beyond anything I could have hoped for. Since my expectation for any major uptick really was zero, this counts as a big late system evolution bonus.
But I know on every parameter compared to a front rank tt, whether an SME, Brinkmann, GP Monaco etc, my Salvation isn't there, but punches well above its weight.
I've spent 6x on it over my initial outlay w Stacore and SOTA/Farad, but this still comes out at less than 40% the cost of a Brinkmann Balance/Rönt.
After maxxing out with Stacore and now SOTA/Farad, the only other significant move I could make would be to move to the front rank with a Brinkmann or GP.

 

[tima]

Tim, if i blindfold you and change the speed from 33,333 to 33,350 you will not hear the difference, that is about the difference between needle in groove, and out of groove. If i change your motor and controller to a lesser type, like a Hurst AC motor running at perfect 33.333 of main line power it will sound lees dynamic with a smeared treble, compared to your reference setup. There are more than one way to skin a cat, your system uses ultra fast micro adjustments on a light platter to keep speed stable. TT's like Peters Micro Seiki and the even more extreme AS 2000 use a heavy platter with a powerful stable motor to create the uninterrupted drive forward, it also evens out the power ripples that become audible with lesser motors and controllers. I have also found, that a flywheel greatly improves the sound on the belt driven TT's, the flywheel increases torque transfer and acts as a ripple buffer, absorbing the micro ripples from the motor poles during operation.

"Did I change the speed or not?" say you to your blindfolded subject.

I suppose I don't really know the numerical threshold of audibility for a single blindfolded instance of comparison.

But I can imagine a scenario where I'd been listening to a table for, say, 6 months, and that table had very stable and accurate speed, say its peak error rate, its deviation from 33?, was 7 out of a million measurements (7ppm). I enjoy listening to this table.

Then, unbeknownst to me, you swapped that table for one whose peak deviation from a perfect 33? was less than 1 out of a million measurements (1ppm). After listening to the new table for a couple hours or so, would I have heard a difference? Yes and the difference would be dramatic, crazy dramatic to say it in Marc way. What was new was the source signal itself.

I know this because I did it and had that experience. Well, you weren't there, but it was a classic A/B/A/B compare and contrast, though no blindfold.

Wrt tables such as David's and Micro Seiki, I have only a general understanding of what you describe as a ripple buffer technique for dealing with cogging or micro-cogging. I have a general understanding of your example how a better or lesser quality motor running at the same speed can improve or reduce sound quality. I have nothing but respect for the designers of great tables and how implementation really matters. I also have my own direct experiential evidence of the difference can make between what appears to us as tiny tiny numbers that consistently take a table closer to 33?.

It is easy to accept the general notion that speed stability is more important than speed accuracy because we can at least imagine pitch differences, wow or flutter. ooooOOOoooo. Instability may be more blatantly annoying. And it is difficult to imagine the audibility of small numerical differences in accuracy. But where the imagination may struggle in acceptance, the ear does not - we can hear the difference. It's not a matter of comparing one effect (stability) to another (accuracy) and choosing. Going from a less accurate to a more accurate table that is more constant in its speed is audible, dare I say easily audible.

 

[tima]

Just for the record, the Roadrunner measures speed with a resolution of 1/54,000 or 0.0000185 (33 RPM) or 1/40,000 (45 RPM) using a time base accurate and stable to 2.5PPM (0.0000025) over the entire commercial temp range (-30°~+60°C). In a controlled temp environment like the typical listening room, the stability is many times better.

Not to be a nit picker my friend, 2.5ppm is 0.00025. :--). Whereas 0.0000025 converts to 0.025ppm. Can you say which it is?

Is the accurate and stable time base a quartz clock?

By replacing the worn bearing with Si3N4 , fabricating new shaft, installing a sapphire thrust, installing bearing liner and balancing the platters the speed stability issue was rectified and the continuous speed corrections disappeared.

Do I understand correctly - you replaced the bearing in your Brinkman with silicon nitride bearing? Or this was a different table?

 

[spiritofmusic]

So Tim, a Monaco 3.0 must be on the cards sometime. And it's claim to superiority will be even greater specs on speed...even more vanishingly vanishing error rate.
Are you confident you'll detect it audibly? Immediately, or over the course of time?

For the record, I heard the GP 1.5 in a fantastic horns based demo some years back, and absolutely loved the sound.

 

[Vienna]

Not to be a nit picker my friend, 2.5ppm is 0.00025. :--). Whereas 0.0000025 converts to 0.025ppm. Can you say which it is?

Is the accurate and stable time base a quartz clock?



Do I understand correctly - you replaced the bearing in your Brinkman with silicon nitride bearing? Or this was a different table?

It was the VPI Avenger Reference Tim

 

[tima]

So Tim, a Monaco 3.0 must be on the cards sometime. And it's claim to superiority will be even greater specs on speed...even more vanishingly vanishing error rate.
Are you confident you'll detect it audibly? Immediately, or over the course of time?

For the record, I heard the GP 1.5 in a fantastic horns based demo some years back, and absolutely loved the sound.

I'm guessing that was Definitive Audio with Vox.

As far as being confident detecting a difference from an even more accurate model, I have no way to answer that. The 2.0's peak error rate from perfect (33?) is 0.8ppm. (A number Alvin wouldn't let me say in my review.) To put that in perspective, 1% is 10000ppm. If you had shown me that number beforehand it would be meaningless to me until I had the listening experience.

Today if I saw better numbers it would be similar - I cannot easily translate a spec to what I hear - would it be more of the same but better? Especially since the numbers would presumably reflect an even smaller deviation? GPA built the 2.0 as an experiment - they knew they could achieve greater accuracy using technical stuff I'm not yet allowed to talk about, but they had no idea what the sonic result would be until they built it. They were sceptical if others would hear what they did - until first reports came in, then they knew they were on to something. Knowing Alvin I'm pretty confident he would not release a new version unless it was genuinely improved by more than a small amount.

I will admit being totally surprised at going from 1.5 to 2.0 - the half-step difference in the model numbers does not, imo, represent the sonic step, particularly given how much I liked the 1.5. It sounds like hyperbole to others so I try to avoid talking about the emotional experience, but it remains the most significant model upgrade I've experienced with any component.

 

[Lagonda]

it would be completely wrong though, for someone to assume that for the desired speed stability, the critical component is only the motor and the controller. In fact the bearing design, belt materials and platter’s balanced well distributed mass are of equal importantance.

For this reason for someone to address and solve speed instability issues besides the speed measurements he will need to measure vibrations and resonances in order to locate the source of the speed issue. A closed loop with speed feedback and continuous speed corrections is just a patch to cover the issue , but it’s still there, affecting the sound.

In the past I used to own a manufacturer’s reference model equipped with rim drive (two motors driving a rim drive disk) and a magnetic driven platter.
trying to correct the unstable speed and the motors resonances , Bill Carlin made for me a new drive with BLDC Anaheim motors (the same that SOTA is using) driven by a high biased class AB amplifier and equipped with the Roadrunner tacho.

The result was a way more silent operation but I was experiencing continuous speed corrections (Condor’s led was continuously blinking), while the Roadrunner tacho was displaying a speed range (33.330-33.339)

I thought that it was the drive and rim belts so I made new from EPDM, the belts improved the situation but still the speed instability was there.

Much later I discovered that the bearing, the bearing thrust and the bearing liner were made with loosely tolerances and even the platters were wobbling. The lubricant was insufficient Too.

By replacing the worn bearing with Si3N4 , fabricating new shaft, installing a sapphire thrust, installing bearing liner and balancing the platters the speed stability issue was rectified and the continuous speed corrections disappeared.

The correction of those issues and the achievement of stable accurate speed was translated undoubtedly into a better sound comparing to the earlier condition, but still that rectified tt was lacking of the sound quality that superbly designed and engineered turntables are offering.

Savvas, one thing are the number, another thing is sound, how did you perceive these constant adjustments sound wise ? I have found that i prefer the sound of the controller without feedback, the constant small adjustments add a smearing to the treble, clarity is higher without feedback. My TT has a air-bearing and a 100lb platter, there is little rumble, and almost no friction involved in operation. I originally used a 800rpm Hurst AC motor, somewhat underpowered for the application, managed by a Falcon controller with RR feedback. Speed was consistent at 33,333 with +/- 0.005 variation with feedback engaged, but with a slight smearing of the treble. Without feedback i was getting consistent 33,333 with only +/- 0,001 variation. Bill Carlin has explained to me that with a heavy platter the system will make small adjustments and constantly overshoot/undershoot the target speed. The same happens with bad traction or bad bearings, as the feedback is designed to correct for long time drift, not adjust for bad design or more instantaneous/constant variations. I am seeing the same tendencies with the AS 2000 and Studer A80 motor that i use currently, run by the AS 2000 controller.. Both David and Bill told me that results where best without constant feedback, but of coarse i had to try it for myself. David uses the controller with no feedback, and this constellation gives me a steady 33.333 rpm, with only a occasional 0,001 rpm variation. I have added a off/ on switch to the cable connecting RoadRunner and Controller giving me the option of instant speed adjustment after warmup, but also steady playback without feedback.

 

[Lagonda]

"Did I change the speed or not?" say you to your blindfolded subject.

I suppose I don't really know the numerical threshold of audibility for a single blindfolded instance of comparison.

But I can imagine a scenario where I'd been listening to a table for, say, 6 months, and that table had very stable and accurate speed, say its peak error rate, its deviation from 33?, was 7 out of a million measurements (7ppm). I enjoy listening to this table.

Then, unbeknownst to me, you swapped that table for one whose peak deviation from a perfect 33? was less than 1 out of a million measurements (1ppm). After listening to the new table for a couple hours or so, would I have heard a difference? Yes and the difference would be dramatic, crazy dramatic to say it in Marc way. What was new was the source signal itself.

I know this because I did it and had that experience. Well, you weren't there, but it was a classic A/B/A/B compare and contrast, though no blindfold.

Wrt tables such as David's and Micro Seiki, I have only a general understanding of what you describe as a ripple buffer technique for dealing with cogging or micro-cogging. I have a general understanding of your example how a better or lesser quality motor running at the same speed can improve or reduce sound quality. I have nothing but respect for the designers of great tables and how implementation really matters. I also have my own direct experiential evidence of the difference can make between what appears to us as tiny tiny numbers that consistently take a table closer to 33?.

It is easy to accept the general notion that speed stability is more important than speed accuracy because we can at least imagine pitch differences, wow or flutter. ooooOOOoooo. Instability may be more blatantly annoying. And it is difficult to imagine the audibility of small numerical differences in accuracy. But where the imagination may struggle in acceptance, the ear does not - we can hear the difference. It's not a matter of comparing one effect (stability) to another (accuracy) and choosing. Going from a less accurate to a more accurate table that is more constant in its speed is audible, dare I say easily audible.

Tim, it seems to me you have a fear of being blindfolded, you might actually like it Your example is not exactly what i suggested. You went from a DD TT with a low mass platter, relying heavily on constant feedback to the same table with better feedback, of coarse there is a big uptick in sound quality by better speed stability. I suggest you have someone dial up or down the speed 0,005 rpm using your same reference table with the super precise/fast adjustment. and then honestly tell me you can hear the difference in pitch. I must admit it takes a lot higher speed change for me to hear a difference, as long as the speed is steady .