Tube question

[Roland GR 88]

I have a Traynor YBA-1 Mod-1 head. It's a 40w, 2xEL34 head made for guitar and I use it for bass as well in my studio through a Berg CN2x12.
I recently blew a power tube and replaced the stock pair of JJ's with a matched set of Mesa EL34's. These were the only ones available at my local store. The JJ's are EL34b's, the 'b' stands for big bottle apparently and the Mesa's are standard EL34's.
Questions; are there noticeable differences between brands of EL34's, EL34b's vs. El34's, and are 6CA7's or KT77's worth considering ?
I usually run the head at 1 or 5 watts for dirt and compression so headroom isn't an issue. Just tone.
Thanks
Alex

 

[beans-on-toast]

Since you are running the amp very conservatively, I think that differences in tone will be subtle if any. When you have slight differences, EQ can turn one into the other. When the amp is pushed hard, there can be differences in distortion.