I've been using a Musical Fidelity A3cr ss power amp (135 watts/8 ohms), a Cary 308T cd, and a ss pre, all plugged into a PS Audio P500 for several years and everything sounds great.
I once tried powering the A3cr amp from a different wall outlet (on a different line from P500/cd/pre) expecting to hear better PRaT but there was only a slight improvement in this area. However, the overall sound degraded so much that I plugged the amp back into the P500. With music playing moderatley loud thru my Merlin TSM mme monitors (87 dB sensitivity), the wattage level on the P500 display reads only around 85 watts although when I switch the amp 'on' the inrush of current into amp causes the P500's display to read 360 watts for a couple of seconds before quickly going
to about 85 watts. Sometimes I will listen to music very loud but the P500's display has never gone over 100 watts.
Btw, the original Power Plants and the P500 produce balanced AC whereas the newer ones (PPP and current) do not.