I bought the Ashdown ctm15 valve head, which sounds great for guitar. It has a ss pre which can dial in quite a lot of overdrive, but it's driving the power stage where the tone lies. It's loud enough to gig on guitar, and as an experiment I gigged it with bass into 2 12" Barefaced cabs, and, surprisingly, that was fine too, didn't need to put any bass in the p.a.
This was a 3 piece in a pub sized room.