I've discovered that I have a dark sounding amp (darker than the Pod I've been using to record demos in the bedroom anyway). So I tried switching the op-amp in one of my OD pedals for the first time using an alternate one to see how it would change the character of the sound. I'd like to try a few more options but aren't sure where to start. I've searched through the forum but most of the info on op-amps is rather vague, "I tried type XXX and that worked for me" type of stuff. Is there are a good summary available of the characteristics of the more common types used in OD pedals?