Okay, I changed my mind ;-) .
This is of no consequence for @ozzy62, as the Aries 2 requires a platter using the inverted VPI bearing. For the rest of you, particularly those with a sense of intellectual curiosity and a burning desire to know the truth. I offer the following:
Way back on 1-23-2012 an Audiogon member posted a question to the community: "Which Is The Best VPI Platter?"
One respondent was "brf", well-known long-time VPI enthusiast/expert and moderator of the VPI Forum: Here is his response (posted on 1-25-2012), in his exact words:
1- TNT 5: 1/2 Delrin and 1/2 stainless steel (mine measures 7/8" Delrin and 5/8" stainless).
2- TNT Super Platter: 1/3 Delrin and 1/3 stainless steel and 1/3 Delrin.
3- TNT 4: 2/3 Delrin and 1/3 stainless steel (I believe brf meant to say aluminum, as that is what every TNT 4/Aries 1 platter I have seen, including mine, is made of).
4- New Classic Aluminum Platter.
5- TNT Early lead and cork combinations (here brf is referring---I believe---to the 2" Delrin/lead platter found on the TNT 1 and Aries Black Knight).
6- Frosted Acrylic.
So the question remains: Why does the VPI website contain mentions of the black "acrylic" platter that was introduced in the Mk.2 version of the HW-19? That question I can't answer.
Another question that all the above raises is this: If the black platters that we are discussing were indeed made not of Delrin but instead of Acrylic, why then would Harry eventually come to the conclusion that the "switch" to the frosted white Acrylic platter (introduced on the Aries 2 and TNT 6) was a step backwards in sound quality? If the black of the earlier plastic platter was Acrylic, the "switch" to the frosted white Acrylic platter would be in color only, surely not a cause for a difference in sound quality?
Here''s what I know:
1- At the Groovetracer shop in San Jose, CA (makers of excellent Rega upgrade parts) I compared his black Delrin, black Acrylic, and frosted white Acrylic Rega platters. The white Acrylic platter looked just like VPI's white Acrylic platter, the black Delrin platter just like the black plastic section of the VPI Aries 1/TNT 4/5 platters I own. The black Acrylic platter looked just like the acrylic top plate of the HW-19 Mk.3 I own, and the plinth of the various iterations of the TNT's I have seen in person. Groovetracer makes and offers both Delrin and Acrylic platters because they sound different from one another.
Here's what Groovetracer states on their website about their Delrin platter:
"Delrin is considered the material of choice for record platters by many of today's high end turntable manufactures. There are several reasons for this but the primary consideration is that it shares many of the same properties of the vinyl record (please Groovetracer: LP's are made of PVC, not vinyl ;-). It also carries more mass than the majority of high performance thermoplastics available, which is important in terms of maintaining speed stability."
"The challenge in using Delrin is that it is quite expensive in raw material form and requires extra attention during the manufacturing process."
2- At the plastics plant/warehouse/fabricating shop in Portland Oregon I visited a few years back, I held in my hands samples of the raw sheets of the black Acrylic and Delrin they manufacture. The two plastics were VERY different from one another, easily distinguishable. It has nothing to do with any finishing operation: the two materials have very different compositions, textures (internal and external), weight, and sonic properties.
The technical adviser looked at my Aries 1 platter, and told me the black plastic top was made of Delrin. I was deciding whether to have him fabricate an arm mounting board out of Delrin or Acrylic, and decided to go with Acrylic, as that's what VPI used.
So, is this horse I've been beating dead yet? ;-)
