Anyway as I noted below I tried the lower gain tube in the center position and I like it. Now I have questions on the other thing he mentions.
Originally Posted by Kegger
When you feel like doing some/a little tweaking, 12AT7's in that config have much more drive then needed, 2 quick helping mods, 1 remove the bypass cap on the driver (little electrolytic) between the center driver tube and each phase splitting tube, 2 is try some lower gain tubes like E180CC, 5965, E80CC, 6829 and such for the center driver tube.
I've been running a VTA ST-70 for awhile now, I just today tried a nice RCA 5965 in the center spot based on the recommendation above...like what I hear!
I'm interested in the second quick mod you mention, but scared to death of it. (zero building experience/etc...amp bought used pre-made by Bob himself). You don't mean literally taking a pair of pliers and ripping those bypass caps of, do you? If it's not as easy/barbaric as that can you describe what needs to get done?
I'm pretty sure I know which part you are referring to, but could you illustrate it clearly?
What might be the negative consequences of the mod?
You're talking about these ones, right?