Korg Monotron-k

[nobada nobody]

So.
I have been lurking portablising forums since benheck, and i never had the time, the resources nor the tools to build one of these bad boys. In the meantime my interests changed, so while this isn't technically a portable console, it uses various techniques learned here, so i figured i'd give a bit back to the community.

Here it is:

Monotron k

(k stands for klavier, or special k, if you're into that kind of thing)


Now for a little back story. I got the monotron a couple of months ago, and if you've ever played with the thing, it has some awesome sounds, thanks to the original ms 20 filter (well technically half of it, since there's no high pass, but nevertheless). It only had a ribbon controller and a pitch potentiometer, which means you couldn't really use it for playing live, especially with other instruments. So i decided to integrate it into a toy piano keyboard, one of those oldies which had a resistor ladder.





After i disassembled it and switch the different resistors with a constant one (100k), i went back to the monotron and took out all the pots, replacing them with connectors:


I decided to frankencase the upper part of the monotron into the case, to preserve some of the style and the original writing:


crimes against consumerism..


testing everything


before spray painting


after spray painting


putting it all together (careful now, it's tightly squeezed)


And that's pretty much it. I haven't done any mods except lfo to eg (i plan on building an expanding module of sorts, adding a pulse wave from the monotron's saw and a couple of sub oscillators, using comparators and dividers, but that's for another time)

Some more pics for your enjoyment










That's about it. Tell me what you guys think

 

[Lightning]

so.. what is it? some kind of midi synthesizer or some such thing?

 

[bentendo64]

Awesome! Looks good!

I know nothing about music stuffs, so I assume this is what you started with?:
http://www.korg.com/us/products/dj/monotron/

So you just connected the pot connections to the resistor ladder?

 

[Bush]

This is awesome! How does the keyboard interface with the monotron if you aren't using the resistor ladder?

 

[Prog]

so.. what is it? some kind of midi synthesizer or some such thing?

If I understand correctly, he started with this, which you play by pushing on a continuous surface:

and then replaced to the crappy surface with actual keys.

 

[nobada nobody]

Yup, that's the synthesizer i used.

About the keyboard
The monotron has conveniently labeled pinouts on the back, and i used the point labeled "gate" as shown here (the way this works is like with old school synthesizers, cv or control voltage: for a different voltage that you feed the gate, you get a different pitch. Thus the resistor ladder)
I tried to use this schematic:
http://picsynth.000space.com/monotron/pitchcontrol.html

But the monotron, unlike the delay, also has a pitch potentiometer, which i wired to another ladder so as to control what octave i'll be in.

There was another potentiometer that controlled pitch, a semi-fixed one. This controlled the interval between the notes in the far ends. Now the monotron has a 1octave-something ribbon, but i was using a 2octave toy keyboard. So i replaced this 102k pot with a 103k one and fine-tuned it by ear.

I'll make a video in a bit so you guys can hear the beast.