Which opamp to use in TS9 pedal?

[Paul Marossy]

I can't really hear any difference between different opamps, either. You can, however, see the differences between some chips with a scope. In terms of waveforms, the FET types look a lot less harsh than the BJT type opamp, such as the JRC4558. An example of a an FET opamp would be the TL072.

Just something I have noticed in my tinkering with circuits and a scope. 

[aron]

I can't really hear any difference between different opamps, either.

I can hear the difference but more importantly, changes like diodes etc... affect tone but can be wiped out by a simple EQ change. However, the FEEL does change a lot with different thresholds and diodes - at least for me.

[jmusser]

I think being able to hear the difference in op amps must come with decades of messing with this stuff, because I can't hear the differences either. I believe if I can plug in an op amp at random, and you can tell me it's a 5532 or TL072, then you're the man, and I'll do the Wayne and Garth "I'm not worthy" salute!

[Paul Marossy]

I think being able to hear the difference in op amps must come with decades of messing with this stuff, because I can't hear the differences either.

Then who's going to be able to tell? Certainly not the average Joe! 

Maybe some people are better at hearing the really high freuquency stuff where you might be able to actually hear some very minute differences in the sound...

[Steben]

mmmm, so the older you get, the better opamps sound?

[Paul Marossy]

mmmm, so the older you get, the better opamps sound?

Maybe. The first thing to go is the higher frequencies, you know.