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

I’m not sure totally different applies, especially when come to Nelson Pass amps. With the First Watt series included; Nelson Pass has become the Baskin Robbin’s 31 of amplifier designers.  If restricted to Pass Labs gear, and again I’m not sure totally different applies, but in the context of the gist of the question at hand, Spectral jumps to mind as leaning towards the opposite direction.

Would love to hear CJ Art line, Ayre, Atmasphere. Clearly high end, unique designs.

@redwoodaudio These would be in my top 5 to try also. Atmasphere, Ayre, Pass, Luxman and CJ...all great choices and established, well-liked companies with well-built gear. I don't know about Luxman support but the other 4 are great.

@OP,
I own both Ayre and Atmashphere and find them to be very close sound-wise. ( MX-R and MA-1). As you might expect, a little more 'rounder' on the Atma and a bit more 'crisp' on the Ayre.- Which is one of the reasons I would like to compare Pass with them.
Bob

I know that the pass labs 250 watt amplifier is the one that they say is the workhorse of their line because it is the most load tolerant aka designed to drive anything.

After going from Pass XA30.8 to Octave v110 (KT120 P-P 100wpc) and back to Pass, I think that nice PP tube amps are a different and enjoyable beast. Much fuller sound, denser soundstage, more immersive on the Octave. VERY detail-oriented, precise, more sparse soundstage with the Pass. I ultimately enjoyed listening to the Octave more than the Pass, but both are extremely good at what they do.

I had to return the Octave due to a tube biasing issue, but I went for an alternative PP tube amp that seemed like a cool value proposition: Wavestream Kinetics Boxter (6550/KT88 100wpc) from The Music Room. No information about it anywhere, but designer is Scott Frankland (of MFA, Wells Audio fame).