[gchuva]

I have a rack where I run my Oppo player to a Denon 4311, which acts as a processor, to W4S monoblocks sitting on the floor.  Which devices should I put iso feet under?  All of them?

[Herbie]

To bring out the best potential of each component and the system as a whole, you'll want to use appropriate isolation feet under each of the components.

Steve Herbelin
Herbie's Audio Lab

[gchuva]

And what products do you suggest?

[Herbie]

Four Tenderfoot isolation feet under each component. If the amps are on carpet instead of a bare floor, I recommend polished granite, Baltic birch or maple platforms or slabs (not available from Herbie's Audio Lab) on the carpet, with four Extra-Firm Tenderfoot isolation feet between each platform and amp chassis (Big Tall version of Tenderfeet if you need the extra height to lift the amps free of the stock feet).

http://herbiesaudiolab.net/compfeet.htm#tender

Steve
Herbie's Audio Lab