Somewhere back in this thread there were reports that the Vivaldi benefits from isolation so I slid a Townshend Sink under the DAC and the improvements were immediately obvious - bass is deeper and tighter and it seems to be more clean overall.
This does not surprise me at all. One can refer to the incredible improvement that Steve Williams is reporting with the addition of his Critical Mass rack system. I remember when a buddy came over with his DAC and laptop to play some music on my system. I had no additional rack space so I simply put his DAC on one of my spare Townshend Seismic Sinks on the floor and the sound improved immediately. This same guy noticed improvements with two of these Sinks under his SS amps. I'm sure there are better isolation alternatives.