I don't really know which parts I should buy and change. Till now I changed the MOSFET from IRF630 to IRF510 and tried diffrent tubes (got a electro harmonix and a Brimar).   What does the Crosstalk improvement do? It will completely separate the channels from each other, right?

Hi I bought a 12AU7 Bravo Audio Amp a few month ago. The first one I received was broken but I got another one completly free and it's pretty awesome. Now I'm trying to repair the first one.   The problem is I dont get any sound output. I hear the clicking when I turn it on and both...