What isolation feet under your amp with great result?

Sorbothane sucks the life out of the music, has a dulling effect, Herbie's is the way to go.

I drank the Herbie’s Koolaid for a while, spent hundreds on many of their products. Can’t say I ever heard an improvement. There are no shortcuts to better sound. Spend more and get a lot more in return.

Have heard great things about these...

http://avroomservice.com/evp-2/

Silent Running Audio (SRA) platforms work great under my amps.  You need to have the platforms made (or refurbished) for your specific amplifier(s), i.e., weight, size, and footer location.  With their platforms, you can use your amp's existing footers.  Their platforms are expensive though.  One of their taglines - 

Informed by its work in the aerospace, military, electronics and medical industries, the company is renowned for the effectiveness of its mission-critical solutions—whether applied to advanced fighter jets, nuclear submarines, electron microscopes or high-end audio systems.