Well I'm finally trying my little new V2 amp.
I almost immediately changeg the stock tube. I think it sounds decent overall but on stoner rock songs the instruments are blurred and I can't appreciate the voice. Even if basses and highs are defined, mid ranges are totally killed.
I am trying these new tubes now, a Philips:
And a jugoslavian International Servicemaster Electron Tube
I can say they improve greatly the amplifier though I prefer the second one. I think it can manage better the whole amplifier.
I would like to try an RCA clear top.