Sound Application for power amps

I've tried various power conditioners including Shunyata Hydra's and while they offer amazing benefits with digital and preamps, I have never thought that plugging amplifiers into these sounded beneficial. I currently am using my 300 watt SS amp plugged directly into the wall via a Purist Dominus power cord, which is fed by a dedicated line thru an Audio Excellence wall outlet. I have been told by a few members that the one conditioner that actually improves the sound of an amp is the Sound Application products. I would be buying used and would like some comments on this issue and which one to buy. I was also was wondering if I would need to put in a 20 amp wall outlet to accomodate the SA conditioner. Thank you