ZEN Instruments

 I stumbled across the VTech Precomputer 1000, learned that it's based on a z80, and looked for a schematic. I couldn't find one, so...

     Here's one more analog drum schematic that I've redrawn. I worked from the drawing found here , and changed the layout for clar...

      I added labels to the last of the three Monotrons, the Duo.

    I have a bit of a fascination with dub sirens. This one, the NJD, is particularly iconic. A schematic is floating around, but it's n...

    I was looking for a solution for generating dual power rails from a 3.7V LiPo battery. I found this DP1912PA board that seems to do a go...

     I've been interested in modifying a Korg Monotron. I found a labeled PCB image at T im Stinchcombe's site here . I found the re...

     A friend made me aware of the CK9561 (aka KD9561) alarm IC. I wanted to understand it better so I could use it in my projects. I starte...