2. analog
  3. 1345605510

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
pcosta
241 posts
 
Suteetat

I owned a custom Minus K for close to four years. I sold it. I found the improvements too subtle to consitantly notice the differences. I sold it after I moved my system to a floor made of concrete compared to an upper floor I had my system in previously. SO unless you have serious floor issues I don't think it is worth it.
Another thing to take into consideration is how big a top you need for an AC-1 because with a Minus K needs to have the load in the center of the table for it to work properly. Having an outboard motor may not allow you enough room if the top is not much bigger than the table.
If you do go with a custom top don't get it from Minus K. It is just a sheet of Aluminum that they will over charge you for.
suteetat
435 posts
 
Thanks for the input. If I go Minus K route, the custom top plate would be quite a bit bigger than the footprint of AC-1 exactly for the center of gravity issue. It is a bit unclear to me at this time though if there is an easy way to see if the center of gravity is properly aligned. If it is a matter of distributing weight until say, leveling bubble level on the platform, I think it can be done easily enough using additional weight

Wall shelf is not an option with my current setup as the nearest wall is not weight bearing and the location would not be anywhere close to weight bearing column.

Pcosta, since you have Raven AC, I assume that you used Minus K with your Raven AC?
pcosta
241 posts
 
Yes I used it only with my TW and I have only had one motor. It is easier to address the centering issues with the short belt for that table.
halcro's avatar
halcro
2,664 posts
 
The 'centring' issue is not a problem if you use a top-plate supported on 4 equally placed 'spacers' over the Minus K stand.
I have checked this directly with Minus K and it's something they recommend.
Just take into account the weight of the top-plate?
pcosta
241 posts
 
Halco

What do you mean by:

The 'centring' issue is not a problem if you use a top-plate supported on 4 equally placed 'spacers' over the Minus K stand.

I would assume the Minus K would not be working as good as it should, not to mention, putting the turntable out of level. In my experience with the Minus K having that top plate lean out of level would be compromising its abilities,
The amount of movemment can be adjusted on the Minus K but you are also adjusting the amount of isolation from its lowest speck on up.
More to discover