Friday, July 1, 2011

Voice of Saturn Sequencer clock IO mod

A while back I was syncing my VoS Sequencer to midi via the clock out of a Kenton Pro Solo and noticed that the clock was slightly off. I remedied this by using the gate out and shifting the notes of a midi sequence until it locked in but realized this was a problem. I discovered that the decade counter that is the heart of the sequencer is triggering on the trailing edge of the square wave of the clock instead of the leading edge. This means that if you try to either sync to an external clock or send clock out, the sequencer will be half a step out of sync. Granted, this can be kind of cool for off time stuff and you may want to do the following mod so it can be switched in and out. The idea is to put an inverter between the clock and the clock jack so the output clock signal is inverted. That needs to go through another inverter before it reaches the decade counter so the clock signal ends up as it was before. This 2nd inverter will also invert an incoming clock signal so things will sync up. I've done this mod on a few and it works fantastically. Attached is a schematic.


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