So I have an old Kenwood KA-3500 stereo amp that I'm thinking of converting for guitar use. I'll be modifying a lot of stuff in it to simplify operation. I've done this before on other amps that were less featured then this one.

I plan to use the stereo output to drive two seperate 12" speakers (it puts out about 40 watts rms per channel), but the input will be mono to both channels. I'm sure that folks here understand that.

My question here is: This amp has multiple different imputs including two tape inputs, phono, tuner, and Aux. I am assuming that the tape, tuner, and aux imputs are all designed to accept a 1 volt peak-to-peak signal, while the phono takes a low strength signal (like a mic or pickup). I'm trying to figure out which input to tap for the guitar (direct pickup input).

I'm guessing that the phono input would be best, but any other ideas?

I have a small Stagg BA20 amp, and I wish to tap the circuit board to create a preamp output (use this amp as a preamp). The output on these amps is driven by a CM1875T audio power amp IC. I know that pin one of this IC is the positive input, so, if I tap into that input pin and wire out to a jack on the panel (so that the board input to that pin now goes to the panel), would I then have a preamp output?

If incorrect, what should I do?  Thanks!