Well seeing that I got $150 off on the amp and have seen (heard) what good tubes can do the the sound of a amp. I just ordered two matched sets of TAD 6L6GC-STR's, a JJ ECC81, and a matched set of JJ ECC83-S / 12AX7's.
It sounds nice now but this should bring out all the tubey goodness in this great amp.
I guess I'm just not in tune with it to know what to listen for. The one time I spent an evening with a guy who was comparing tubes, I honestly couldn't hear a difference in the power tubes. The preamp tubes I did, but this is what I don't understand; from my experience with tubes, they don't start warming up until around 30 hours, and at least with the tube mastering gear I've got they don't really develop their character until around 100 hours. It's not like an enormous difference, but at least as much as I was hearing between the preamp tubes this guy was comparing. So what I don't get is I don't think I could choose a tube unless I could hear it after it's burned in. But I guess after you've had experience with them you'll know what their going to do.
At a prac- maybe... just