More juice without the extension cord?
To me, a transformer humming like that is that the voltage in is too high. That is why my amp stopped humming when plugged into P20 because I could lower Vin from 245v to 240v. Maybe the long extension dropped the voltage along it enough to make the amp transformer happy
Using a P12 with XA60.5’s, BHK Pre, DSS. The P12 does make quite a difference for the XA60’s. Definitely worth every penny
Nice! My favorite Pass amps.
What load does the P12 say your running at with your configuration. Think spec on the XA60s is 400 watts each channel. Given the Class A configuration of the amps, I assume at idle you’re running near 1000 watts? Thanks!
Did you or an electrician wire the new dedicated circuit? Perhaps there is a ground issue with the new circuit. A simple tester should determine a basic problem. Not sure what impact the extension cord would have on the previous circuit, other than adding a little more resistance given the extra set of connections. Assuming the new circuit is on the opposite leg of the breaker panel as the previous circuit you could try shutting off all the other breakers on the same leg of the panel to see if there is something contaminating the power. If it stops the hum, turn them on one by one until the culprit is identified.
They are only 400 watts combined for me (200 per Monoblock). I’m slightly different, but running my P10 with XA60.5s, BHK Pre, SACD player, Streamer, and Stellar Phono pre, I’m only at ~550 watts total (depending if I have all running, anywhere from 55-60% total for P10). And agree, @audiojan convinced me to try into the P10 and it definitely makes a difference.