Thursday, February 14, 2013

Whippany Rhythm Master modifications

A while back I modified my Whippany Rhythm Master analog preset drum machine from the late 60's/early 70's. This normally sounds like your typical cheesy rhythm box to accompany organs from this time, but with a few mods you can open up some possibilities. There are no chips I messed with here, or no markings on the circuit board to give you. I pretty much just replaced some of the trim pots inside and some of the resistors with potentiometers mounted to a panel and fit inside a wooden case.  

 You can check out the pictures here to see some of the wiring that I put in. The trim pots(now removed) control the output volume of the various instruments, including separate controls for the noise and the pulse of the snare sound. To find which other resistors controlled the sound parameters, I shorted out the resistors around the trim pots while the machine played.

 At some point, I will go back in and try to find the trigger points for the sounds. If I ever get the external triggering figured out, I will have a pretty bad ass analog drum module for less than $50. In the meantime, you can check out a video of how this sounds right now.

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