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
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.
It's hard to beat a wall-hung shelf (especially if mounted on a masonry wall) for reducing the effects of structure-borne feedback?
I use factory bench with 4 inches slap of black granite right now with my TW. I have a friend that in the past had tried quite a few different types of stone for amp/speaker stands etc before and he found best result using black African granite (supposedly it has higher density than average granite!) In the past I tried slate but the result was not great. At least for those that I could find locally anyhow. I was trying to get a quarry to cut me pool table slate slap and it was a big hazzle and trying to get them to polish slate smoothly was almost impossible (may be I need a pool table factory for this). Anyhow, the one I got was not so great. However, I just located a used Symposium ultra locally that is big enough for my Raven AC-1 so hopefully I will try that in the next few days.
Vibraplane is also something I want to try or perhaps Minor-K. However, I am still thinking that eventually I might try to get BN 3 motors unit for my Raven so until I know for sure what size the turntable platform will need to be, I don't want to invest a lot on platform for my turntable just yet.
I use a wall shelf and have tried a number of isolation feet. The problem with heavy granite slabs is the wall shelf might be overloaded. You don't want the table falling off the wall.
I have used a number of feet, stillpoints, black ravioli, Herbies Isocups. the New stillpoint SS Ultra are marginally better than stillpoints+ risers, not enough to justify the added cost, but better