The Noomerang is a wah pedal by B Tremblay of runoffgroove.com fame. It’s a variant of the Maestro Boomerang wah, which itself is a nice alternative to the usual Cry Baby clones, with some added goodies. Unfortunately, the schematic seems to have slipped by without receiving much attention (having only been mentioned once on diystompboxes.com – here’s the link). It’s not terribly different to the standard Boomerang circuit, the most important differences being the addition of a Q trimpot and a 33k resistor added to the board so that a standard 100k wah pot can be used instead of the 25k pot found on the original Boomerang. But both additions are clearly improvements on the original.
The layout has been designed to fit a standard wah shell of the kind sold by Smallbear. I’m very happy with the sound of the Noomerang – a bit smoother and richer than a standard wah. Initially I used 1uF film caps for C2 and C5, but I got DC leakage that resulted in a crackling noise, like a bad pot, at the treble end of the wah’s range. It seems that the polar nature of electrolytic caps is an advantage here (perhaps tantalum caps would work even better, but I haven’t tried them).