Hii. I'm new to the forum and need some help with my JCM900-4501. The Tubes were Red-plating and the bias Ran away when I bought the Amp. I fixed this issues by exchanging the Infamous C15 Cap in the bias circuit, the bias was way to cold when maxed out, so I lowered the value of R7. After that i could bias the pair of new el34s properly, but the max Amp Volume was still way to Low on both Channels, since the Amp was completely Stock I replaced all electrolytic caps on the Power- and Preamp board. Still the Amp is not loud enough, of course I checked the FX-loop with a Patch cable > Same result. The Voltage on the Powertubes seems resonable to me: 3rd Pin: 450V; 4th: 450V; 5th: -32V (on both Tubes) Now i dont know what Else could be the Problem, do somebody have some Suggestions what to Check next? Thanks a lot in advance!