VPI Ceramic Platter

Don't put it all on Dangermouse. The collaboration between DM @ Sparklehorse is very good!

I am surprised that no one took up String's casual comment that his "superplatter" (Have I got that right?) was not perfectly round. Of course, replacing such a defective platter with almost any platter that is closer to tolerance should result in an improvement, most notable in terms of pitch stability.

Also, if I learned my Mark Kelly turntable physics correctly, use of a smooth vs a grooved platter addresses belt "slip", not belt "creep". Mark was always careful to distinguish between those two phenomena. Further, the fact that the cross-section of a belt is not "100% round" is indeed another source of speed error in belt-drives, but it is not the central issue in belt creep, I don't think. Belt creep derives from the fact that the tension on an elastic belt is not a constant for every part of the belt. Belt creep can be reduced (but not completely eliminated) by using a non-stretchy belt and by configuring the drive so that as much as possible of the platter circumference is in contact with the belt.

Finally, wouldn't it be true that Stringreen's listening experience can only be relevant to those who use the VPI rim-drive? The drive system is SO different from belt drive that very different factors are at play in determining the end result.

Finally finally, according to theory, introducing a new material between the vinyl and the platter (assuming the VPI platter is aluminum coated with ceramic) would result in a change in the efficiency of transfer of energy from the vinyl to the platter. (Whether it gets more or less efficient would depend upon certain physical constants which I am too lazy to look up.) Energy has to go past the vinyl/ceramic interface, through the ceramic layer, and then past the ceramic/aluminum interface, in order to be dissipated. At each interface, if energy transfer is not perfect (never is), some energy can be reflected back to the vinyl. This is not to say that bleeding energy from the vinyl is critical; lots of people seem to like to use mats and such that practically prevent it.

I use a Kenwood L07D. Kenwood made an optional ceramic mat for it, back in the day. Those who own(ed) it tell me it sounded bad. I think SAEC also made a ceramic mat that can be used on a variety of turntables. I don't know whether either or both of those were solid ceramic or ceramic-coated, but I think the Kenwood one was solid ceramic.

Lew,

You are right. There is ceramic, and then there is ceramic. The ceramic that first comes to mind for most of us is the vitreous type, like in dishes. That's made from clay, but the tech ceramic is completely different. Silicon nitride balls are examples most commonly discussed in audio, and they have no clay base. Another example is the gold drill bits you see at stores these days.

The VPI platter may be chromium nitride coated. That is a PVD coating commonly used on industrial punches. It is deposited on the surface of the base metal inside a vacuum chamber at around 750F. The end result is a surface hardness that is off the Rockwell scale. It is very, very hard, and measures at 2,000+ on the Vickers scale. You won't scratch it, and you won't wear it out. It will always stay shiny and polished, so I like the idea for that reason.

Lewn....you're correct. My rim drive table MUST have a perfectly round platter, otherwise the out of roundness makes the turntable ride out and in to accommodate the different diameter of the platter and each point as it turns. The result is that the Superplatter forces the turntable back and forth. The VPI arm as you know rides on a sharp point, so the result was a rocking of the arm, which REALLY was awful to look at.... and much less awful to listen to (though I could hear it). The Superplatter is not made any more because it was so difficult to make it absolutely round. On another point, the Superplatter had a kind of tubby sound. When I went to the Classic platter, it was simply a revelation...the soundstage, the stability, the new information, etc. was wonderful. The difference between the Superplatter and the Classic is enormous...the difference between the Classic and the Ceramic is less so, however, still a very worthwhile upgrade.

I guess the Superplatter really was not "Super".