SLAW
"Wow! I was listening to the 1st pressing of Jimmy Page/Robert Plant "No Quarter", (which is an excellent sounding lp), and since it was in need of flattening, I put the Stillpoints LP isolator onto the top of my McCormack DNA 225 (Platinum) that is sitting inside (on the bottom shelf) of a Solidsteel 5.2 rack, the amp's shelf, which is a BDR, "shelf-for-the source" platform that is itself, sitting on three original Stillpoints isolators, the amp is isolated more by Symposium Rollerblock Jrs. w/ ceramic ball upgrade. Whew!"
Sounds like you need to send that DNA-225 Plat into SMc Audio and have the StillPoints Standoff treatment done to your amp. It will put the vibration reduction right where the source of the problem is happening, preventing any vibrations from reaching the circuit boards.
Steve has mentioned many time at how much these make a such a hugh difference when installed