I really would like to solve changing the LM13700. That will be so easy!
By the way, I tried, just to be sure, the other LM13700 (Tayda) from the Snow White (without this issue, but with a not working Decay pot, as I said. Maybe there's a link?) and the result is the same.
To tell this issue with few words the effect (the LM13700?) work, but bad. Because I guess it boosts too much, so I got this very loud initial attack (at least three time the normal volume), and, I'm trying to guess, for the same reason I heard this high pitch click when I switch off the effect after the release time, and a bit when I turn on, It's not the usually bump when we got without the pulldown resistor. And I got a bit too much volume jump: louder when I play softly (because the too much boost) and less loud when I play harder (because the compression, perhaps the good working part).
This issue is absurd, the Engineer's Thumb has pro and cons, but I get an effect unusable, I don't think that nobody notice this, except me.

The funny thing is that the same loud initial attack I got in the Auto Wah DOD FX25 I dismessed, it was loud even in the decay, just with a bunch of low frequency, but that was the wah effect like in the heel position.
Midwayfair, how did you realize that Tayda had bad LM13700 chip? It doesn't work at all or you got a sort of issue like me?
By the way, I even more sure I'll never buy transistors or ICs from Tayda.