Espoused by guitarists like Robben Ford, Sonny Landreth, and Nalle Colt, the ZenDrive by Hermida Audio continues to live up to overdrive connoisseurs. This particular overdrive is an NE5532 Op Amp based drive, and the one ending up on the bench today suffered from an op amp gone awry.
The original complaint was that no output could be heard when engaging the effect, but when bypassed all was well. On opening the backplate and removing the circuit board I was surprised that the op amp used in this unit was seated in an IC socket. This made the repair much easier (thanks Hermida Audio!). I removed the op amp, breadboarded it within a simple buffer circuit and, sure enough, the op amp’s I/O terminals were stuck at the rails. Replacement with another NE5532 fixed the issue.