ok, all better. WAY easy fix.
i did end up using anti parallel 3mm red leds in parallel with r3, the gain resistor on the first stage opamp. that helped slightly, but not enough. still, if i really hit that sucker, horrible and serious distortion.
so first thing i did was change the opamp. i had a tl062 in there, and it was kinda noisy as well as distorting. grabbed an op275 outta the bin, first thing i grabbed. that took care of most of the noise.
still distorting harshly on transients. so i did the no brainer move, lifted the input connection on the board, and grafted a B500k trimmer in line with it. pin one went to the ground pad, pin 2 to the in pad, and the original connection from the footswitch to pin 3. now i can turn down the input just enough to reduce the transients and get rid of that nasty distortion… i mean, face it, a 5 volt circuit doesn’t have much of a swing before it hits the rails… reading about 78k between wiper and ground on the trimmer, which is about perfect. i can’t make it distort no matter how hard i whack that sucker now. used the volume control to bring the circuit back up to unity gain, which is roughly 12:00 now instead of off.
sounds silken and pristine now. no noise <the series resistance of the trimmer lowers the noise floor slightly by filtering some highs just slightly> no hiss no more distortion. i took some crappy phone pics, but they’re too lame to post, really.
so anyways, thats my q&d fix for distorting transients in the guitarpcb adverb circuit, should anyone else face the issue.
hope it helps. rock on!