What 50wpc or higher amps have a totally different sound from Pass Labs, in a good way?

Ayre on one hand, and Luxman on the other are good counter points.

Listen for yourself.

@redwoodaudio
Ya know, the XA ".8" amps sound different from the older X ".5" version amps, and a little different again up and down the range.  Or, some  variations in FirstWatt or even older Threshold. Depends on what speakers you have too, right?  

What type of change in sound are you looking for, if you have an idea...What's missing or what are you wanting more or less of in sound?

The Yang (opposite) would probably be Chord or Krell.  Switching power supply, error correction, much brighter sound profile.  They are wonderful sounding with the right speakers. 

If you want a higher power alternative to Pass, AVM has a similar sound with its Class AB products.  Decidedly warm and works well with brighter speakers and a ton of power.   

@erik_squires .
I concur. 
In fact, I'd love to compare Pass to Ayre, one day.
Bob