RT2/50 (and M4) Preamp tubes

[Bucksears]

I've never owned an amp that was as sensitive to tube changes as this setup. Not referring to the preamp tubes in the Egnater modules themselves (haven't swapped any of those out yet), but the 12AX7s in the RT2/50 and the two that are in the back of the M4.

Here's the rundown: I started noticing that OVERALL my M4 seemed to have less punch/gain than it did before. I recently put in a set of EH EL34s in channel 1 of the Randall and have not been impressed with them yet; bumped it over to Ch 2 (which has JJ 6L6s) and everything sounded awesome.
So I don't know if this is a problem with the power tubes on Ch1 or the preamp tubes that associate w/Ch1. I might try swapping in a set of GT EL34Ls that I recently picked up, but have to ask this question:

How much affect on the tone/sound do these (non-modular) 12AX7s have on the M4 and RT2/50?

Thanks
Buck

 

[HughJasol]

So I don't know if this is a problem with the power tubes on Ch1 or the preamp tubes that associate w/Ch1. I might try swapping in a set of GT EL34Ls that I recently picked up

Try putting the great-sounding JJ's 6L6's in the poor-sounding Channel 1, and vice-versa (not forgetting to re-bias!). Does the the crappy sound move with the EL34's to Channel 2, or does it stay with Channel 1?