There are a lot of bits and pieces of information for you to patch together. Wish you could try before buy.
I used to own the 11a and then the 12's. Never owned xs versions. I currently own Cary SLI-80 and prefer triode mode over ultralinear. I also prefer KT88 over EL34.
Premier 11 and 12 era CJ amps are a bit more euphonic than more recent CJ amps, overall. Sweet lovely sound, but it could be a bit much if your other gear is "sweet" also. XS is sweeter yet, EL34's sweeter yet.
Generally I agree with the notes above. Triode sounds more natural, will always give you less bass control, softer treble that is perhaps more natural, and may or may not be powerful enough for your speakers. EL34's and triode mode are both naturally a bit sweeter with softer bass and top end compared to 6550/KT88 or ultralinear mode.
Finally, I remember also that the 8xs was either HP's favorite amplification or in the top two or three for many years. That is saying a LOT. I think that was at least a decade ago.
I used to own the 11a and then the 12's. Never owned xs versions. I currently own Cary SLI-80 and prefer triode mode over ultralinear. I also prefer KT88 over EL34.
Premier 11 and 12 era CJ amps are a bit more euphonic than more recent CJ amps, overall. Sweet lovely sound, but it could be a bit much if your other gear is "sweet" also. XS is sweeter yet, EL34's sweeter yet.
Generally I agree with the notes above. Triode sounds more natural, will always give you less bass control, softer treble that is perhaps more natural, and may or may not be powerful enough for your speakers. EL34's and triode mode are both naturally a bit sweeter with softer bass and top end compared to 6550/KT88 or ultralinear mode.
Finally, I remember also that the 8xs was either HP's favorite amplification or in the top two or three for many years. That is saying a LOT. I think that was at least a decade ago.