Atma-Sphere vs Pass Labs Class A

I have compared Atma-Sphere M-60 to Pass Labs XA-60.5.

However, one was a mismatch with my speakers and the other was not.

It will surprise me if anyone has compared these two brands on speakers that match both equally well.

In terms of heat, I would say both amps were about the same, with the Atma-Sphere perhaps running a bit warmer, but not by much. The Pass Labs will warm a room.

It will surprise me if anyone has compared these two brands on speakers that match both equally well.

Very well said. They are designed with fundamentally different philosophies, and among other things have drastically different output impedances. Ralph has an excellent paper on this at his site:

http://www.atma-sphere.com/papers/paradigm_paper2.html

Regards,
-- Al

Thanks for the input. All other things being equal, I guess given the lack of difference in heat output, I will stick with what is working well for me now.

Al, thank you for the link to Ralph's paper...

XA60.5 draw 200W per chassis; M-60 draw 300W per chassis.

Dealer disclaimer.

I'm sure Ralph would tell you if your speakers would be a good match for his amplifiers. 300 series Rowland amps run quite cool and are very "tube like".