WOW! Yes, it decreases the gain a little bit but JerryP from FJAmods recommended this to me and damned if he wasn't right! Before, I ran my gain at about 1:00 and now I bumped it up to about 2:30 so the loss of gain is no big deal. There's still plenty there but the difference is that you can dime the gain and still have clarity. The amp sounds SO much clearer and more defined it's unbelieveable. It didn't change the voicing any, just the clarity. Now I know why Madison comes stock with some 12at7's! I don't know if it will work with any combination of tubes but it's one of the best sounds my ears have heard in a long time with my tube setup.
V1: Tung Sol 12ax7
V2: Tung Sol 12ax7
V3: 9th Gen Chinese 12ax7
V4: 9th Gen Chinese 12ax7
V5: Balanced JJ 12at7
Power Tubes: SED 6L6's
all of that = NO mud, none at all. I can't wait to have the house to myself again
I only got to play on it for about 20 minutes after discovering this.