So I may be purchasing a Bassman 70 with a matching 2x15 for a pretty good price from my school. Yes, I know these are the stepchildren of the Bassman badge, but I like the way this one sounds. It need some looking at by a good amp tech and I think it'd be an amazing sounding amp. I've played the amp a bit and I have been able to get it to give me a bit of grit when crossing the channels over, but not much. I know this amp is known for being super clean, and I do like that, but I was wondering (since I'm a tube newbie) if I could increase the "gain" by changing the tubes out? If so, what tubes are recommended? Are there any other tricks for making this amp a bit dirtier? I have some nice pedals, so getting it to break up more isn't necessary, but it'd be nice. I'd be using this amp for bass, baritone, and guitar so I'd like to keep it pretty versatile.