[CaptainTrips]

So I must be doing something wrong here. It was my understanding that changing out pre-amp tubes was a very easy thing to do and an easy way to modify the way that your amp sounds. I have a Fender HotRod Deville . . . . I want to make it a little calmer, a little quieter and a little warmer. So I decided I would replace the stock 12AX7's with some 12AT7's.

My plan was to put a 12AX7 in the phase inverter and the 12AT7's in the V1 and V2 spot . . . . but as soon as I do that every single tube rings microphonic. I was like . . . . wtf?

So I messed around a bit and it seemed like every tube other than the original tube in the V1 spot caused every other tube to be microphonic. But when I put the original 12AX7 in the V1 . . . it was fine . . . . and in fact it sounds great now . . . .

So I thought it was an issue where for some reason on this amp I need a 12AX7 in the V1 . . . . so I went out and got a 12AX7 and put it in there . . . . . all the tubes become microphonic again . . . but as soon as I switched back to the original 12AX7 . . . . it was back to sounding great.

So then I wanted to test out the tubes . . . I put the 12AT7 in my 5 watt Fender Champ and it was microphonic. So then I tested out the 12AX7 in the Fender Champ and it worked fine.

There seems to be absolutely no rhyme or reason to any of this . . . I just dont understand.

And just FYI . . . the tubes that I am using as replacements are Groove Tubes Gold Series and the original tubes (or the tubes that I acquired when I got the amp) seem to be Sovteks.

Any idea what is going on here?

Right now my final setup, which like I said, sounds great is:
V1 = original 12AX7
V2 = Groove 12AT7
V3 = Groove 12AT7