Op amp Clipping

[Sir H C]

I don't guess I had thought of that before.  That may account for why some diode to ground circuits have 1K resistors before the diodes and others have 10K.  Hmmmm.   

Yep, for instance, do not use the 5534/5532 op-amp as that can drive a 600 ohm load and some CMOS opamps assume that the output FETs are good enough to handle a short, so they don't protect just let the voltage droop, but most have sense resistors that pull the output down when there is a short on the output (i.e. a diode starts conducting) that will clip in an interesting way and not risk latchup stuff.

[Ben N]

There are no opamps' rights organizations that I know of.

LOL.
Brings to mind images of PETS (People for the Ethical Treatment of Semiconductors) members flinging a fluid suspiciously like capacitor electrolyte at fuzzboxes in public places...

[PacoPicoPiedra]

i've tried just the second 2 gain stages on their own now, sounds the same as the first but I'm also getting some oscillation which seems to vary in pitch a bit depending on guitar volume and contact with the strings, weird cus its all wired up the same, is it likely to just be a bad opamp? don't know that I actually need the two more stages anyway, I just want more gain than I can get out of the stock circuit, any ideas?

[WGTP]

Tooo much gain can result in oscillations (which you may or may not be able to hear), gating, etc.   Suggestions:  1) reduce the 1meg resistor in the last stage to 100k and increase the cap to 470pf  2) try just using 3 stages  3) go back to 2 stages and reduce the the 10k resistor between stages to 1k and increase the 100n cap to 1uf  4)  use the standard set up with LED's in the 2 stage feedback loop.  This should increase compression/sustain and distortion and MAY not sound that much different.   

[PacoPicoPiedra]

thanks man that was just what i was looking for 
dropping the 10k down to 1k was just the extra push it needed, I did think I wouldn't be able to because of dropping the input impedance to the second stage but it seems to have done the trick. theres still oscillation but much less than with 4 stages, am I right in thinking increasing the caps in the feedback loops will roll off more top end to help alleviate the remaining oscillation?
the coupling caps are already at .47uf but i might drop them later, just have to strike a balance between bass response and avoiding mush

[PacoPicoPiedra]

right finally settled on 560pf in both feedback loops and the 10k jumpered completely, sustains for days and no oscillations

[ItZaLLgOOd]

Any soundclips??

[PacoPicoPiedra]

http://www.sendspace.com/file/11xccg

recorded with a jag through the fuzz, straight into akai sampler, forgive dubious guitar skillz