Korg Monotron

[jamiewoody]

to me, instead of bending what is already there, adding a few more filters would be the thing to do! a resonance filter so you can play the beginning of tom sawyer from rush....BBBZZZZZZZZEEWWWW! lmbo! an envelope filter would be tasty too...

[Gordonjcp]

I've actually found some pics online of the inside - http://www.timstinchcombe.co.uk/synth/korg.html - here.

From the description it sounds like it's a similar thing to a Gakken SX-150 with a Korg35-type filter similar to early MS-series synths.  I bet you could build a better one with things you find at home ;-)

[electoyd]

i think most of us probably are building something better, Korg better pull their finger out before we are showing them the way forward lol

[Gordonjcp]

Well, liinked on that page is a circuit that approximates the Korg35 filter.  It's not a very good filter, with pretty poor frequency tracking and a fairly variable resonance characteristic as you sweep the cutoff.  The distinctive sound is caused by the input voltage affecting the biasing of the two transistors used as the voltage-control element in the filter network, which basically modulates the cutoff with the input signal.  The filter VCO mod on CEM3394 does the same job.  The Gakken SX-150 filter is broadly similar, it's worth noting.  I think it's 12dB/octave where the Korg one uses two filter circuits in series to give 24dB/octave response.

Maybe something like an Arduino could be used to do the oscillator and envelopes, and then an analogue VCF/VCA circuit to process the sound...

[jamiewoody]

could someone give me the lowdown on ribbon controllers? i know that the korg triton has it. are they hard to make?

[Matt the Modulator]

i had a look at making a ribbon controller but my basic attempts have all failed but i have saved some web pages

http://www.paia.com/ProdArticles/dual-ribbon-howto.htm
http://www.electronicpeasant.com/projects/ribbon/controller.html

post up something if you manage to make one work

[kloroplaster]

Heres some mods for the Monotron with schematics and video documentation: http://www.dinsync.info/2010/06/how-to-modify-korg-monotron.html

[jamiewoody]

the MUSICIAN'S FRIEND description has "filter any external source using the audio jack input"!!! i must have one!!!

i want to learn to make one too...i have some bucks in paypal...buy one of these or component order...hmmm...i am low on potentiometers and some things i really need.

[Gordonjcp]

You can build a nice external filter based on the Steiner Synthacon VCF quickly and easily.  There's even a version from a guitar synthesizer that will run off 9V.

Interestingly, it has high-, low- and bandpass *inputs* rather than outputs, so you can use it to mix different sounds and sweep the filter across to do a bizarre crossfade.  Have a listen to the recording I posted in the AVR homebrew hybrid synth thread.

[jamiewoody]

i'll look that up, thanks!

i still haven't built a vcf. i want to start with the simplest one first though. as few components, etc. and kind of build my way up.

[Matt the Modulator]

this vcf is pretty simple with low or bandpass output
http://www.magicmess.co.uk/electronics/12dbfilter.php
and this oun uses only 6V
http://www.magicmess.co.uk/electronics/6vfilter.php

[kloroplaster]

I've had great fun sending my bent sounds through the Monotrons filter - recommended!   

[jamiewoody]

an easy, handy mod....build a box around one of these, with a footswitch, and phone jacks so it will resemble a stomp box...add it to your pedal board!

[selfpreservation]

i got a monotron for my birthday its cool it could do with an lfo trigger button though, work van studio is growing,  i can wait to road test it against my ms20 but the builders out the back of my studio have put the building in danger and i cant go in there hat to take all of my gear and put it in the conservatory i am going to kill them seriously whre casn i get a crossbow  

[selfpreservation]

having played woth the monotron i can see it needs never gonna be an ms10/20 without the modulation possibilities that said i can see  a few improvements that would make it cooler, the lfo retriggers when you press the ribbon controller which is great but you also get the osc at the same time so the osc needs a cut switch or vol control also an input to retrigger the lfo say from a drum machine trigger out would be good , a proper output would be good as would be cv cutoff control and gate in , i cant really see the point of adding pitch cv as its a pretty ordinary sounding osc without the modulation possibilities of the ms20 any ideas?