TW Raven Owners: Set Up Questions


Through the magic of sweet talk, I turned my Orbe into a Raven and mounted my Graham 2.2/Benz LP.
I am looking for a isolation base for the Raven. I have a 1 3/8" piece of granite coming soon so I can ditch the MDF I use now (a temp. meas.!) Symposium, SRA, HRS, etc., can anyone share their experiences with isolation bases? I saw the thread about loosening the Stillpoints.
Initially I had an issue with using the rough side of belt. The belt shimmied up/down on the pulley at a specific spot on belt. Also, the speed fluctuated and I could never get it dialed in with the PSU. So, I went to the smooth side of the belt and then raising the back side of the motor (unscrewing one of the isolation feet) slightly moving the belt down from "center" on the pulley. This moved me from 33.2 to 33.3 and I have no more belt shimmying and the speed is rock solid.
I'd appreciate any tips/tricks etc.
gerardff
TW suggests slate for a platform, which can be seen in photo's on TW's web site. I don't think granite is the best material to use, although slate may not be the best either. I am in the process of trying different platforms as well. I have constructed a platform of 3" thick Baltic birch plywood (4 layers of 3/4 inch). I cut a void in one of the middle sheets and filled it with #12 lead shot (smallest size) and will Formica the top, I might also Dynamat the bottom. I purchased 2 pieces of custom cut 2" thick slate which will go on top of this. I’m going to listen to the table on the platform alone, then on the slate on top of the platform, then try a different platform made from some type of advanced resin. If I don't get too lazy, I am also going to experiment with points, Rollerblocks and Sorbothane in different places. Remember the ideal durometer and amount of Sorbothane depends on the weight it is supporting. You'll find pretty much all you need to know on Sorbothane's website. This is probably all overkill and there may be very little, if any, differences as the manufacturer indicates the table is not very sensitive to its support, as long as it's reasonable. I hope that gives you some ideas.
I used to have an unsuspended SME Model 10. I first tried Mapleshade brass cones on a 4" thick maple block. Not great. I preferred placing the turntable right on the top shelf of my Zoethecus rack. Then I bought a Townshend Seismic Sink for about $200 on Audiogon. Huge improvement. Better dynamics, more clarity, better detail, and deeper, more articulate bass. Then I bought a Vibraplane platform and it did eveything the Seismic Sink did, only more so. Finally, I installed a 136lb steel ballast plate to preload the Vibraplane and this improved the performance of my SME even more.

I'm a big believer in proper isolation now, especially for unsuspended turntables like the Raven. I strongly recommend a Vibraplane.
Thanks for the tips. The slate is a stop gap measure until I can find something better. It can't be worse (can it?) than the single sheet of MDF it's on now. I have it atop a Naim Fraim set, which are designed less for mass loading and more towards light weight isolation/dispersion. I have a feeling adding significantly to the shelves mass will defeat their purpose. I may be headed back to using a wall shelf. I have one now but it wasn't installed to handle a 50 lb. Raven. I will have to re-engineer its placement if I decide to use it again. I would contemplate a SRA, Symposium, etc, but I'd really like to be able to try one first so I can decide if I like it's effect. At least with the granite it only cost me $20.