I use Herbie's Iso-Cups under my tubed poweramps and Tenderfeet (is 'TenderFoots' the plural of the brandname 'TenderFoot'?) under my CDPs and preamp. They sound plenty fine to me, but I'm no GEA who hears (or thinks he hears) all sorts of subtle differences. I judge these things in the long term and remove them if I think their presence is decreasing sound quality. My equipment rack is high-mass, with 2" maple shelves and 1"-diameter verticals, and is spiked to the concrete floor. See it in my System .
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