ARC ref 75 tubes 120 vs. 150’s?

i have a ref 75 w kt120 but never ran it with kt150’s

the amp needs an upgrade to run the higher bias kt150 i believe... it is not just plug and play

i also have a vt100-2, w kt88’s... to me the ref 75 is sweeter and more quiet/blacker in background than the vt100 - the vt100 has a little bit of hash in the background, but with twice the output tubes the vt100 definitely provides a bit more drive on dynamic swings - how much treble ’snap’ the vt100 provides is a function of what input tubes you use as well...

J J

Thanks, Which sound do you prefer the VT or Ref 75? 
Separate question, have you heard the AR Ref 210 monoblocks? My buddy has a pair to sell for $8k but I can’t afford them now, just curious how they sound ....thanks