The Jubilee is best when you get the Output Master just at that spot where you feel it kick in, just like an extra gear. That spot usually is around 6 to 7 on the old vintage Silver/Black Jubilee amps. My Clone reacts a bit differently - somewhere in the middle of a 2203 and and 2555. I run my Jubes Lead Master 7 to 10. Then try to get that Output Master up, but still is too loud in most situations to run that sweet spot of 6 ish. My Jube 2555 Clone also has a PPIMV. The reason the 2203/4 and the Jubilees have that different master volume reaction is due to the audio signal levels coming upstream before their respective master volumes. The 2203/4 amps have no diode clipping and then the audio signal swing is much hotter in a 2203/4. The Jubes is lower and and also a bit more compressed and controlled. And then also, the Jubilee master volume pot is a 250K and the 2203/4 is a 1MEG . . . .