They are all Op Amps, I sent the TDPRI guy five 4558 to put in his. I replaced mine with 2134PA. A lot of the Peavey amps are 4558 or 4560.

It is important to note, chojin, that a lot of the newer amps are not socketed. They do just solder them right to the board (I'm pretty sure the Bandits these days are direct mount.)