Ok, how would I do that? I want to use an extrernal Pre-Amp and power it with the Power-Amp in my amp head, but I dont know how to. and can I enforce the sound through a 4x12 Cab?
Plug your guitar into your pre-amp. Then plug your pre-amp into the effects loop return on your amplifier. This bypasses the pre-amp in your amp and lets you use your external pre-amp.