2008 RMAF – – – all things analog.

Dear grooves: IMHO I don't think that that poit was missed, things are that we were argue on TT speed accuracy and speed stability and what could alter the platter speed stability.
This subject beguin with a comment that Doug posted about stylus drag and its influence on that platter speed stability and that's why we don't go in deep to any other source ( other that the TT it sef ) that affect about.

We all know that the analog source is probably the most imperfect " world " to music reproduction but at the same time I know too that the ones in this forum agree that the analog source is the most beautiful and enjoyable one for a home muic reproduction other than a live event or a Studer one with original master recordings.

As always things are that everything has its own trade-offs, take the TX-1000 that fix the eccentricity of the LP, well it is not a perfect machine from the point of view about its tonearm or about its DD motor or suspention: anyway is worth to hear it only because its eccentricity fix function.

Now, IMHO the digital source is almost perfect but like Teres point out it is not " perfect ", btw nothing is.

All that analog imperfection world makes that any one of us ( including a pro-reviewer like you ) that cares about music and about music reproduction have to take extremely care on the right set up and right choice of hardware ( synergy, the real one not for compensate errors in the audio chain. ) at each link in the whole audio chain.

Some of us are truly " perfeccionist " about ( that's why we discuss about the relationship between stylus drag and platter spped un-stabilities. ), my point of view is that pro-reviewers must be ( at least ) in the same way and for what I read through your reviews and other people reviews some are far from there.

My thoughts about pro-reviewers is that al these very special people have a great responsability: help for the analog high-end grow up faster and with real quality improvements in any step that the analog industry take it.

It is sad for me to say that certainly ( today ) that is not what is happening from my point of view ( I could name it many examples of that ). This is not the time or the thread to analyze in deep about, I hope that over the time all us have the opportunity to return on the subject because we need to improve, we need to be better, we need to " dream " again.

Regards and enjoy the music.
Raul.

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.

I would imagine that pitch fluctuations caused by stylus drag are less than pitch fluctations caused by 1)variations in motor speed itself, 2) Groove's eccentricities, and 3) record warps causing speed fluctuations as the stylus must effectively move faster over bumps to complete one revolution at 33-1/3.

The last is quite audible if you have an even slightly warped test record that includes a steady pitch (assuming, of course, that the steady pitch was steadfastly done).

Intuition only, does anybody care to do some measurements?
Jeff

Jj2468, I should have mentioned this before. There are various types of speed anomalies that that are not manifested as pitch fluctuations. Very short term speed variations show up as smearing, lack of detail and often harshness. Longer term, shallow variations tend to make the sound sluggish and dull. Only a small subset of problems in a drive system sound like pitch variations.

It's interesting that the benefits from jitter reduction with digital playback sounds much like what I hear with improved analog drive technology.

Chris

There's a lot to catch up on in this thread, and I'll do my best to be brief and yet thorough ... well ... maybe not brief ...

Speed Errors.

There are various types which correlate to the magnitude and distribution of the error. Chris alluded to this in the stylus drag discussion. At the lowest level is IM distortion discussed in my post above, and loosely equivalent to digital jitter in the sense that we don't hear this as pitch change or wavering but rather as a combination of harshness, a paradoxically rolled off top end, and bleached out harmonics in the mid-bass. As we work our way to longer time domains, we begin to hear timing errors - like the band isn't completely on the beat. Increasing the time domain further, we begin to hear shifts in imaging and pitch until we reach a point where nausea sets in for some of us. It's important to make these distinctions when we talk about speed.

Selection of Music.

I agree in general that acoustic music is critical to understanding what's going on, but this focus on period instruments is more a point of familiarity and reference for our friends on this list than anything else. It provides one (and I emphasize one) means of triangulating on the truth.

For an alternate, equally valid reality, listen to Bill Monroe, Doc Watson, Mark Knopfler, Neil Young, acoustic Jorma Kaukonen, John Fahey, Cal Tjader, Charles Mingus, Kathleen Battle, Talking Heads, Scissor Sisters, etc. and they'll all tell you something equally important about what's going on with your rig.

One of my favorite torture tests is to play a capable soprano going full tilt. Dense music has its place as well, and in this category, you can learn as much from Heavy Metal (even though I don't like it) as you can from full scale romantic pieces.

Rock 'n roll and other electronic music presents a challenge to understanding what's going on, but well recorded rock can also tell you things that you can't hear with acoustic music. You have to be watchful however. Listen to Neil Young playing his beat up Fender Tweed Deluxe, and if you know the sound of those amps and their harmonic overtones, it's unmistakable when a system gets this right.

Period music (Academy of Ancient Music) will tell you about subtlety, nuance and such. Other genres will tell you something different. When we had our Saturday night after hours session at the Audiofest, Palasr brought an AC controller which we listened to (designed by the same fellow who's working with Win on the Saskia controller as well as with us). Well, we're still hunting down a 3-phase motor, and the 2-phase we were driving was relatively crude sounding compared with our legacy controller.

If you listened only to pop and rock, this crudeness would have been lost on you, as bass lines had nice punch to them. A shift to acoustic music told the rest of the story however. Drej and Palasr will agree, I'm sure. One of the main dangers of trying to reach a conclusion when listening to electric music is that the distortions in the recording process can be masked by electronic distortions in your system.

In my humble opinion, a system needs to do it all, and if you limit yourself while you're evaluating, you may well be limiting your ultimate outcome. So, if you listen only to period instruments, should you also invite Jazzdoc over with his Scissors Sisters records. The reverse would be true as well - don't listen only to electric.

Ultimately, you're making choices, but listening to all different sorts of music at a minimum will expose you to different worlds, and the fellow who tells me that Woody Guthrie doesn't have a story to tell me and that all of the valid music was composed by white guys who died a hundred years ago is equally self-limiting as is the reverse. Ultimately, even if you listen to music written by dead white guys, you can still learn a lot that's relevant to you by listening to modern music occasionally.

Cheers,
Thom @ Galibier