[quote name='tayste_2000' post='605702' date='Sep 22 2009, 03:48 PM']Going to try this week the 12AU7 mod, apparently according to people on Talkbass it's less of a mod and more of a correction, removing a bottle neck from the design of the amp, giving it more headroom, more responsive volume controls and a more responsive mid control.[/quote]
fwiw Mark's new Mesa already has a Mullard 12AT7 in the drive position. I think it makes a great difference and made the EQ much more responsive. Good luck and look forward to hearing how you get on