I've got 5 of these from every iteration (that i'm aware of). Time to get rid of the dupes. These are great sounding units that work well with bass and acoustic or electric guitar. I've run them in front of amps, into the effects loop, and direct into a power amp. The filter control behaves like a semi-parametric eq to dial in preferred tone. Runs on 9v (battery included). I've noticed no difference in performance between the grayface and blackface models.
Consider trades for overdrive/distortion pedals. Price includes shipping.
Consider trades for overdrive/distortion pedals. Price includes shipping.