Tag Archive | VCF

Monotron Delay, a few mods more

Jes joo, moving on with the Monotron stuff. First up, certainly worth mentioning is this mod by Stexen, that another modder Dan wrote me about: Replace the keyboard potentiometer with a 500mm version!

Drop in a Spectra Symbol SoftPot such as this one, and the added precision should aid landing specific notes way better. I certainly am tempted to try this, but adding one would make my planned extender module grow in size too much. Thus, adding external CV/Gate control makes more sense at this point for me.. But then again, mounting this SoftPot to some additional box and wiring it to the pitch CV mixer through a series resistor might be one option.

SoftPot. Must.. refrain.. from.. typing.. silly.. cannabis jokes!

On a completely different approach, adding this and turning the synth into some sort of a ‘mini-guitar’ might make a fun mod.

Other than that, I’m tired of typing ‘Monotron Delay’ all the time so I’ll start using the more convenient abbreviation ‘MD’ instead. With future scribblings in mind, whenever its this synth and the abbreviation, no I’m not talking about Sega Mega Drive ;) Read More…

Monotron Delay, a few mods

I’ve given plenty of thought for all kinds of mods for Monotron Delay, but the amount of possibilities confuses me to the extent that I’m unable to nail down a solid approach at once. So instead of trying to come up with a single decent set of mods, I figured I’ll just start with something basic, add / test mods one by one and see what I end up with.

Korg Monotron Delay

Just to sum up what I have in mind, my main idea is to build some kind of a detachable ‘expander’ box that will dock with the Delay. This box will house some additional controls and connectors that would be otherwise impossible to fit inside the original casing. What these added bits will be, remains to be discovered.

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Odyssey, dual VCF

As mentioned before, this seemed like a must-have mod. During the years Odyssey was manufactured, the filter module evolved from a 12dB/oct version to a 24dB/oct version and the design was changed from a bi-quad OTA version to a Moog-style transistor ladder version. Having both of these version incorporated in the same synth would give a larger “palette” to work with, especially if/when external signal/control inputs are added.

Dual VCF board with few IC sockets installed

So yeah.. Nothing too overly difficult with this board (and once I had all the parts) besides the few spots yours truly forgot to solder and then wasted time on measuring and scoping the obvious.

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Odyssey, VCF replacement

Came across ARP Tech’s Dual VCF module earlier this week and was instantly inspired. Whilst later Odyssey’s (models II & III) come with a 24dB/oct low pass filter (model 4075), the Whiteface is equipped with a 12dB/oct model (4023). Despite the latter is generally considered more musical, having a steeper cutoff slope naturally produces more classical “synth” (resonant?) sounds. Moreover, as ARP Tech’s module has both, having them both in a single synth would kick ass.. To say the least ;). So today, I decided to etch a PCB for the module!

Dual VCF board with few IC sockets installed

Luckily enough, the Odyssey service manual does provide instructions to upgrade model I synths for the 4075 module so installing the completed board should be a walk in the park. But first, I need to order some parts.

Not that there’s anything wrong with the filter module on my Odyssey, far from it. The dual cutoff mode just outweights maintaining the original parts at this very moment! Promise I’ll make the installation reversable ;)