Is 20w enough?

Class A or Class AB?

My Vox AC15 (Class A) can hang with drums, but all amps are different.

If you're doing heavy stuff you'll probably want more wattage for the sake of headroom.
 
Good to know. As far as I can tell the poweramp is class a/b (the amp in question is a Jet City JCA20h). Like I said headroom shouldn't be an issue as the amp would mostly be getting used for crunchy rock and blues tones.
 
The Krank Rev Jr. 20w I had could compete with drums at rehearsal when I had one running into my Mesa 4x12. However, the tone was so ridiculously saturated from the power amp. I would say at least get 40-50w tube, I know I wish I had the 40w Krank back then after the first time we jammed with it.
 
Good to know. As far as I can tell the poweramp is class a/b (the amp in question is a Jet City JCA20h). Like I said headroom shouldn't be an issue as the amp would mostly be getting used for crunchy rock and blues tones.

My JCA20H has zero trouble keeping up at rehearsals with a 4x12 cab. I've borrowed it to a friends' band who play basic rock stuff like Foo Fighters and stuff, and even though the drummer is a really heavy hitter, it cut through just great.
 
I haven't tried my JCA20H in a band setting yet but it should be plenty loud enough. This 20W all-tube head should compete with most 50W solid-state amps in terms of loudness.

How do you like this head? I just got mine and love it - I have the matching cab as well. Will be doing some tube swaps and a couple of mods incl changing the 1x12 to a V30. The JCA22H with extra gain channel just came out - should have held on a little longer for that one but will do the mods on this instead and the cost will be the same.

Jarkko did a couple of tracks reamped with his JCA20H stock and the tunes slay!!!