Mark IV preamp tube replacement

[rcc]

I have some new preamp tubes I'd like to load into my Mark IV. Specifically, a couple of
NOS RFT ECC83's, C9 12AX7's, and Penta 12AX7's. However, I'm a bit baffled as to
where they'd work best.

As such, I wonder if you kind folks might shed some light on the Mark IV preamp tube
layout for me?? I've got the manual up and see that each tube's triode services different
(in some cases vastly so) functions of the amp circuitry. Also, the staging doesn't seem
consistent in that V3 and V4 "A" affect the lead channel gain stages along with other
things, etc... when compared to other amps where V1 and/or V2 almost always have
greatest affect on primary and secondary gain staging (particularly in high gain amps, of
which I use predominately). Any insights greatly appreciated!

 

[Lesgoldy]

There is a great deal of subjectivity here. Two seemingly identical tubes can sound different. In addition, take a tube out of one Mk IV and it may or probably will sound different in another Mk IV. Experiment and find what works best for your amp and your ear!

 

[Shep]

i would put the best sounding ones it the most used places. eg RFT in V1 V2 and/or v3 then the penta's in V5 and the C9 in 4. Easy should sound good.