Best CDP isolation device you use?

Resolution Audio Opus 21 sitting on 'large' DH cones (the smaller rubber feet on the cdp are junk). This sits on a Machina Dynamica Nimbus, which in turn, sits on a custom made Sound Anchor platform (w/spikes going through the carpet and a three-point contact on top).

I found the Clearaudio Magix to work very well. They are expensive, but when you consider they totally decouple the CDP via magnets from any floor/shelf born vibrations, it's probably worth it. You can also save money by not having to invest as heavily in specialty equipment racks or bases.

2nd on the nimbus. nothing else really compares

Good or bad I just installed a Sklan isolation platform under the titanium cones under my CDP and I'm blown away. The shelf was the best isolation device I have used or added so far. I have brass cones on most components with good results but this platform has added a dynamics to my system that I id not know I could get. My best tweak but then again every little bit helps. Usually.

I've tried BDR cones, Stillpoints and Feet of Silence under my DAC. The Feet of Silence made the most positive difference. The contrast with Stillpoints was instructive - using the Stillpoints the music lost its bloom, and sounded overdamped and constrained. The Feet of Silence let the music breathe mone freely. Frankly, the BDR cones made very little difference to the sound.

This is under an Audio Note DAC 4.1x Balanced, so I presume that the suspension provided by the Feet helped isolate the output tubes.