Murfman said:
I figured the preamp tubes were shaping most of my sound. Mike B at Boogie replace all my tubes (preamp and power) when he recapped it and re built the effects loop, etc.
I'm wondering now about these newer power tubes. They are Mesa tubes that say STR 430. Down on the base they say 16 AC YEL. Are these real cold tubes?
I'm wondering if I should yank these and go for a warmer Tube. Anyone with any Tube suggestions? I like really like raunchy, warm, black face fender tones...early Pete Townsend, Keith Richards, SRV stuff.
-Murf
Hi Murf,
Preamp tubes will have a greater impact on tone shaping than power tubes ...start w/ preamp first.
Yes, start one tube position at a time. But FIRST have that tube map or you'll be flying half blind. The tube map will tell you that position such and such determines the clean channel, or just the lead, or 2nd gain stage of the lead ...whatever the specifics, you should know them before you start subbing in/out tubes. But as a starting point, your V1 preamp tube will be the first gain stage for
both your channels.
Think of preamp tube "gain structure" as a scale:
12ax7 = 100%
5751 = 70%
12at7 = 60%
Now these are general parameters, and each tube mfg differs considerably in tone and gain, and of course there are further differences between current prod and NOS. FWIW, I like RCA 5751 NOS a lot (and do use them), as well as NOS Mullard CV4024 (12at7), and TungSol 12ax7 (these are current prod re-issues, and sound great) ...all IMHO of course.
So with your tube map in hand, think about your tone: do you want to affect the amp globally? Do you want to affect just one channel? Is shaping one channel really more of a priority than the other? There will be some compromises you must make as a given tube's task may be shared between both channels. Bottom line is trust your ears. Pop in your 5751 in V1, for example, and live with that for a while. Play the same riffs in just one channel (say, clean). Then swap back. Play same riffs more. Then switch back again. Take breaks knowing ear fatigue will set in and diminish your sensitivity to highs.
FWIW, this took me days to dial in each amp I've done this on ...may take you less time, but I am a big believer in being objective and not just change stuff because "it must be good." If you are patient and methodical, you will eventually find your personal recipe. I have for both my Boogs and a Fender ...and I love my tone for it!
Hope this helps you a bit