Unless the amp power supply is a switching type(very rare) a large power supply is desirable but heavy due to a large trnasformer. Great power supplies don't show up in standard amp specs but are the most significant factor in the amp's performance.
Also if you like the sound of the Pass that's hard to get. A big factor in this amp besides rich class A before going to A/B is there is no overall feedback loop like over 99% of amps. No loop feedback makes a big affect on an amp's sound.