Dual channel amps

[Fossilshark]

If you wanted two channels for two guitars to play on (like the peavey bandit 112 my guitar teacher uses) would you need two seperate preamps and power amps or can you just wire another input jack in parallel.

[Enzo]

Do you want them to both sound good?  Or do you just want the sound of two guitars at once.  And do you mean playing at the same time?  or playing one or the other but both still plugged in?

Guitars don;t all put out the same amount of signal.  What would you do if you wired two jacks together and one guitar has four times the output as the other?  What if one guitar is really bright and the other really bassy?

You really SHOULD have a preamp for each instrument.  If you just want to have two guitars going so you can tune them together or something, then it doesn't much matter.