I tried to follow this thread and went cross eyed. Maybe it is my limited intellect. All I know is that Springreen's original post is correct. What follows includes a lot of opinion based on limited or no experience with the product under discussion. I also cannot understand the broken English of Raul, which is unfortunate. Perhaps someone can offer a synopsis of his main arguments that would help to elucidate me?
I own one VPI metal arm with dual pivot, one VPI 3D arm with dual pivot, one SME Series III arm, and one SL1200GAE with gimbal arm. Properly set up they all sound quite good when mated to compatible cartridges and amplified with high quality electronics.
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With respect to the question concerning clamping, I have a Stillpoints LP1, which I use interchangeably on both my VPI Prime and on my SL1200GAE. It makes a difference sometimes, but not on every record. Generally records that are flat and 180 gram or heavier seem less affected by it. I also have a Periphery Ring for the VPI and it definitely makes a difference on any record that is warped. So much so that the Prime is my go to TT for warped records, regardless of any other consideration. At the same time, for records that are not warped I hear no difference is sound with or without the use of the Periphery Ring. In the interests of complete disclosure, my Prime is controlled by Phoenix Engineering Roadrunner/Eagle so speed accuracy and stability are pretty much the same with the ring or without.
With respect to the effect that the 2nd pivot has on the VPI arm it is extremely easy to back the 2nd pivot off and away from the pressure plate once set up to hear and see the difference. It is doubtful that anyone who does this will decide after experimentation that the 2nd pivot does not provide a positive benefit.
With respect to Raul's arguments concerning unipivot tonearms, they are not clear to me, again I find it difficult to understand him, this is a language barrier problem for me, so perhaps I am misunderstanding? Anyway, he seems to be arguing that there is some inherent "problem" with unipivots in the area of stability at the cartridge-stylus interface with the record groove. He states this as a fact, but offers no data. I would like to know what exactly the "problem" is with the data to back it up. I am skeptical that there is any real problem.
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Raul,
The link you provided is for a sales pitch of the Mark Levinson/VPI turntable. Please send the link again. Thanks.
Bill
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This is a response to Raul's contention that there is a "problem" with unipivot tonearms. I am studiously trying to avoid the exchange about VPI and overhang. I had read all of Raul's posts, watched the You Tube video (actually I saw it several months ago) and so on, but did not find it particularly enlightening or persuasive. It falls far short of proof in any scientific sense that a problem exists with unipivot tonearms. Yes they wobble a bit at first drop, but stabilize very quickly. I have measured the tracking performance of several setups over a number of years using test records such as those from Shure and Ortofon among others. Properly set up, the ability of any given cartridge to track well is not noticeably different when mounted in a unipivot tonearm. This can be heard and observed using an oscilloscope. That is a fact. Cross talk for any given cartridge is not measurably diminished based on two arms of comparable quality, one double gimbal type vs. a unipivot. That is a fact. As any stylus wears I have carefully observed the patterns of wear for cartridges mounted on quality arms of various designs and have not observed any aberrations in wear patterns that resulted from unipivot arms. This has been done using a Herr-Wildbrugg microscope, Model M3 or M5 starting in 1975 or 1976. That is a fact. So based on my years of experience setting up turntables (professionally 1970-1979), and the observable facts cited herein, I will state my opinion that there is no inherent problem with unipivot tonearms. They are different and not to eveyones' liking, but functionally they are fine. If you don't like them, don't use one, but you have no cause to malign the design.
Regards,
Bill
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Raul,
I am having an extremely difficult time comprehending your message. Extracted from your last post is the following example:
" Your " facts " about can’t prove that I’m wrong in my main " at micro levels unstability in any unipivot tonearm ". Reason is that those measures were not made it to prove it but to prove other targets.
We have to know what kind of measures where and how to achieve it to prove a specific subject. This time: at micro levels unstability in unipivot tonearm designs."
I have no idea what you are trying to say here. Really I am at a complete loss. Would you try again?
It seems you are trying to make some point about instability due to wobble, but it is not clear to me what it is. Moreover, it is entirely unclear to me what the practical consequences might be? If it is to make the point that unipivot arms sound different than comparable double gimbal arms, I concede the point. But, we must also acknowledge that two different double gimbal arms sound different from each other too. Where does that lead us?
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Perhaps this post is a progression too far, but may I suggest that we agree that there is no one, single, absolute "right" way to do anything in audio. That is true for every aspect from tonearms, to amplifiers, to speakers, to wires...whatever. Each of us has preferences in equipment, music and so forth. Accordingly, looking for "proof" of something like this is somewhat analogous to the search for the Holy Grail.
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"Bill's facts/tests were not created to measures the stability in tonearms subject. So in this regards means nothing."
I was going to let this go, but you have restated it and it is becoming obvious that you are ignorant of the scientific method. What I offered were several indirect proofs that unipivot arms perform well. Indirect proofs are repeatable, independently verifiable, and are sound science. That they mean nothing to you tells me that you are no scientist. You claim to know what you are doing, but this belies that claim. What "means nothing" by contrast are the You Tube clips you referenced which do not measure anything, do not provide a verifiable proof of anything and do not allow independent verification. Your "proof" is not science. It is worthless.
"Almost all audiophiles are focus on what we like and not in what SHOULD
BE....
"
You have repeated this sentiment several times and it must be dealt with. How do you propose to establish "what should be?" And since we are talking about music, we are also talking about many intangibles such as for example acoustics. Are you suggesting that it is possible to establish one set of parameters for "what should be" that would be universally correct for all tastes and all situations? To illustrate: small group, acoustic performance, "should be" set in an entirely different venue than would be desirable for a full opera production. So what do you mean by "what should be?" Then too, are you advocating the elimination of free choice in our musical enjoyment? If Adolf Hitler had his way, we'd all be Wagnerians. Can we all agree that the world is a better place without that sort of restriction (no offense to any Wagnerians intended)?
Finally, your response to my tongue-in-cheek reference to the Holy Grail is telling. The obvious answer to your "why not?" is because such a thing does not exist. It is becoming clear that you are on a one man quest for something that a) is not practical and cannot be obtained (and may I say parenthetically, Thank God!), and it would not be viable even if achievable because as audiophiles we are all a bunch of free spirits who happily want to go our own way, make our own choices, in short, follow our own muse.
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With respect to the OP's experience with the VPI dual pivot modification, in case anyone missed it, I agree with him, have two VPI arms that are used interchangeably on my Prime and both have the dual pivot modification. It definitely is a worthwhile modification for anyone who owns a VPI unipivot arm. FWIW, one of my arms is a 3D and the other is metal. Based on my limited experience with two arms, I am of the opinion that this mod benefits all VPI unipivots.
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"I have a couple of questions that I would think be of concern to all VPI
owners: @billstevenson, You may be positioned as our best form of
information on these questions?
(1) The factory off-set setting
of S2P distance by 2mm on my Classic 3....is this difference on any of
their other TTs? The Prime? Why is it a good thing? If it isn’t, why are
we experiencing it?
(2) Is there a good reason why a designer of TTs and tonearms won’t reveal their preferred cartridge geometry method?
"
I wanted to avoid this can of worms. I don't know if I can help clarify or just add to the confusion. My Prime has a S2P of 261.5mm actual, vs. the specified 258mm. I had a protractor constructed for the actual S2P to address the issue. Matt at VPI offered to fix mine if I returned it, but in my mind as long as the actual S2P is accounted for it shouldn't matter. Not everyone will agree with my decision, but it seems to work just fine. I will offer conjecture that the reason why any manufacturer would not want to reveal a preferred cartridge geometry would vary depending on their priorities and overall philosophy. Why limit applicability of their product? How critical is the geometry issue in practical terms? Records are imperfect anyway. Get everything dialed in for side A only to discover that things are skewed for side B (this happens all too often).
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I apologize for being absent for a few days. I live is South Florida and Irma has turned our lives upside down here. Anyway, without power and no air-conditioner it is difficult to get excited about turntables. I have no idea what you are trying to say in your post above Raul. Perhaps someone else can interpret for me? Just in case my last post was not entirely lucid, my point was that no matter how precise we try to be with TT setup, the medium is inherently imprecise and compromise is part of the game. No matter how careful we try to be, the records we play are themselves not perfect: not flat, holes not centered, equalization imprecise, etc.. Everything is a compromise. We do the best we can. And you know what? Don't despair, our efforts are not in vain because as most of us know full well, a vinyl record very often sounds better than the digital equivalent for all it's claimed perfection. And we also know that we can strive for further improvement through refinements in setup, experimentation, ever improving cartridges and pre-preamps etc. And, in the process we can have a lot of fun.
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