Though it is not an e.q., along similar lines: use a BBE Sonic Maximizer, and emphasize the bass process. The sonic stomp can do this, in a pedal format. Don't overdo it - if you find you have that tendency, consider using a different cabinet instead.The things to do is stick an EQ in the loop and get some low end, much more than any tube change.
I have to disagree - there can be profound change in bass. Have you ever tried this? I have, literally hundreds of times. But tube changes do have a smaller degree of influence than do speaker and/or cabinet changes.Changing tubes is unlikely to affect the bass at all
Just a thought: you don't have the cabinet on a stand, now, do you? That'll reduce lows quite a bit, depending on your floor type/size.
- T
Changing tubes is unlikely to affect the bass at all, as pretty much every tube amplifies all the way down to 0 Hz (DC) with no loss of gain. Bass response is entirely affected by coupling caps, the output transformer, the speaker and its enclosure. I suppose a tube that's weak in high frequencies might make it sound like the bass is being emphasized but I suspect that's not the sound you are looking for.
Miles