opamp descriptions

[ruger9]

DIY "fun" - opamps

Just for fun, thinking about switching around the opamps in my OD pedals- all the pedals take 9V, any chance I could harm something? Or is the worst that can happen "it'll sound like crap"?

Furthermore, I've scoured the net looking for general descriptions of the opamps used for this stuff, and it's very hard to find anything, except for  "which tube screamers had which opamps", is there a site that gives characeristics for the different opamps? (I realize many more components than the opamp makes a pedal sound the way it does, but I've got to start somewhere...and the opamp seems to play a big role in tone.)

I've been DIYing my guitars, amps, HOUSE, for years- but this is my first educational leap into stompboxes.  Much appreciated!

[petemoore]

As far a linear amps, I think there are two basic types
 Singles
 Duals
 Also LM308's [with compensation pins].
 If the units are working, you should be able to discern singles from duals by looking at how they're wired, and where V+ is connected in them...connect a battery, and Black DMM lead clipped to ground, set for 20v range, touch the red lead to pin 8 [9V there...probably a dual] ...9V at pin 7 would 'likely' be a single OA.
 If the chip is in a modulation effect, or something other than dual or single oa, of course the above methods will not tell you that.

[puretube]

not exactly for this topic, but nice, anyway:

http://focus.ti.com/lit/an/sboa092a/sboa092a.pdf

(2MB)

[Paul Perry (Frostwave)]

The op amp doesn't make a significant difference unless (and it is a BIG 'unless') it is overdriven to where it doesn't act as a perfect op amp any more for part of the signal cycle.
Now since op amps aren't intended to have this done to them, not much attention is paid   to this area when designing them (except to perhaps take precautions to stop them latching up, where the output reverses & they don't come home no more).
So, run outside of the 'official' guidelines, an op amp might do anything..