What isolation feet under your amp with great result?

@tweak1 , Geoff has been saying "mass on springs" for years, and after the past two months of trial and error I have ended up with springs under my heavy speakers and amps.  The spring stiffness (i.e., spring rate), load capacity, diameter, and height are all important considerations.  I have used heat shrink to damp the single springs and even that was a learning experience wrt the size and thickness of the heat shrink used and how those factors affect the performance of the spring, as well as the need to put a hole in the heat shrink to prevent an air lock.  The heat shrink also improves the look (pics on my system page) and prevents scratching on the bottom of your components or the tops of your rack shelves.  I also have a bunch of Herbie's products here (Giant Fat Dots and Gliders) and based on my experience so far I would have a hard time deciding whether springs or Herbie's footers sound better. 

I like the feet these guys are making,  Turntable Phonograph Vinyl Record Player lsolation Feet – Mnpctech

I have only used one isolation vibration product and that’s the EVP’s. I used these under my speakers. I placed them under the speakers for about a week a just let the music play. I then set aside several hours where I played music I was very family with and would play the music w the EVP’s then remove them and play the music over again. The EVP’s definitely have a positive affect on the sound. When I removed them it sounded as if the life was sucked out of the music. With them the music sounded cleaner(more transparency), more dynamic, just overall more musical. I still would like to experiment with more isolation systems bf making a purchase, EVP’s made me a believer that concept of controlling vibration and its affect on the music isn’t just selling snake oil.

The EVPs by A/V RoomService Ltd. seem to have a strong following by those seeking a decoupling alternative.  The primary isolation appears to come from an "air spring" resulting from Owens Corning 703 or 705 one-inch thick rigid fiberglass board, which is then faced with #4 brushed Stainless Steel sheet and either felt or rubber.   I have considered making these and believe you could probably get most of the way there by simply installing the board.  I would also be curious to try using the board to make equipment platforms but since I already have platforms and am using springs under my speakers I have not yet been motivated enough to spend the time to make the stuff.