#1
where should i place a 12AT7 in a Blues Deluxe RI to lower preamp breakup? right now the stock preamp tubes(fender labelled sovtek junk) break up just at 2 on the volume when i pick hard. was thinking of tossing a few 12AT7s in there but if i just used one where should it go? i heard in the PI, but also in the first gain stage etc. sooo im not sure where it should go now.
#2
I recommend the first preamp spot. Otherwise known as the input tube.
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#3
^^^ +1

V1 is a likely culprit, but I wouldn't rule out other problems.

Unless you have major boost from fx, or are using active pickups, you shouldn't be topping out the preamp at 2, even with deep picking.

Try the 12at7, but the phase inverter on this amp is somewhat notorious (to me, anyway, I've seen two now that eat PI tubes for breakfast).
Switching to Tung Sol 12at7 in the PI helped.

I gather it's because of this (from Harpamps):

Phase inverter uses two sections of a 12AX7, configured in a differential
pair, rather than the more common single section voltage divider
inverter.


If the 12at7 at v1 doesn't work, or brings gain down too far, try swapping this tube, too.

I would actually recommend the 12at7 at PI, and a good chinese 12ax7 at input.
#4
putting it in the PI would greatly lower the amount of gain the power section sees.
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#5
Correct me if I'm wrong, but I was under the impression that in terms of gain level it was always...

12AX7>12AY7>12AT7>12AU7

I'd have imagined that using a 12AT7 would significantly reduce the gain level as its harder to overdrive a 12AT7 compared to a 12AX7.
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#6
One sidenote is that the 12AT7 sounds like total crap when overdriven, because it draws a lot of grid current.

Try a JJ 12DW7. It's a dual triode, 12AX7 in one side and 12AU7 in the other. That will cut your gain quite a bit. If you want more cut, try a 12AU7.
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