07-06-08: RadioheadokplayerDitching the Technics TT feet for the brass cones was a big improvement. Before that I had Technics feet on the butcher block, or sometimes Technics feet on Vibrapods on the butcher block, but the brass cones straight onto the butcher block was noticeably better and exposed the music's inner detail for the first time.
johnny not sure how "less wobbly" isolation cones is better than the technics tt feet alone resting on vibrapods which in turn rest on a butcher block with again the vibrapod also resting underneath the butcher block.
I just added the washers and got another incremental improvement. I may try Vinylvin's method and increase the washer diameter to span the collars on the bottom of the turntable. My next step after this is to replace the Vibrapods under the butcher block with cork/rubber blocks.
I found a supplier for cork/rubber blocks in any number of sizes. An 18"x18" sheet is only about $32. I'm thinking of putting an entire layer of cork/rubber under the butcher block instead of 2"x2" blocks.
Since I noticed an improvement adding the washers to the brass cones, I suspect the much denser and heavier Mapleshade threaded Brass Heavyfeet would work even better. But they're $160/set, so I'm waiting on that, especially now that I'm upgrading to Mirage OMD-15 speakers and may be getting a high current amp and bi-wire to drive them.
In answer to Tvad's question, yes I level the turntable religiously. I started with the rack, which has three uprights and adjustable spikes at the bottom. I used a 12" carpenter's level, checking in 3 directions for each shelf before adding the one on top. Then when I put the turntable on the top shelf, I checked again. The Dayton cones are also adjustable, as the tips are threaded and can be adjusted relative to the body of the cone. I do try to avoid having to do that, and I was able to get the turntable level while keeping the brass cones screwed tightly together.
As an alternative, shimming the Vibrapods from below with playing cards or similar shouldn't affect the sound.