i have 4 JJ ecc83 and some chinese unlabeled 12ax7 and 1 NOS tung-sol.
so i was wondering if anyone had any suggestion as to where to place everything. i play metal along the lines of metallica LOG.
I would try the Tung Sol in the V1 position and the JJs in the rest.
V1 is the most important stage for your overall sound. It is relatively easy to switch out preamp tubes by putting your Mark IV on standby and pulling out tubes and replacing them (one at a time is the best). Although getting at V1 is sometimes a little tricky for me. You also want to be careful since after awhile the preamp tubes can get pretty hot. If you don't like the Tung Sol in the V1 you can switch out with one of the JJs.
I have achieved very believable Metallica tones with Mesa chinese tubes and the V on the EQ. Also keep in mind, the Mark IV, as well as most Mesa amps, is very sensitive to any knob change (treble, bass, mid, presence, gain, volume)so be patient. I think most on this forum who use their Mark IVs will tell you that the "Metallica" tones you seek are all in the Mark IV. You may need to spend alittle time with her to dial her in though. I would also check out the settings thread for a place to start.
