Un chti coup de reverse engineering, avec grosse loupe, une résistance sensible à la pression (ou éventuellement un clavier déporté) et hop, un chti synthé pas trop mal. Si quelqu'un pécho le schéma, je prend mais je doute que l'on puisse le trouver, du moins pas avant quelques années.....Allo Korg, pour les seriel moders ???? Ory, des sources....???

(répond pas "meuh non")
j'ai trouvé ça ! ! !
The Korg Monotron (
http://www.timstinchcombe.co.uk/synth/korg.html)
The Korg Monotron created quite a stir when it was announced in early 2010, as it is described as having
"...the same highly acclaimed VCF circuit as KORG's classic MS-10 and MS-20 semi modular synthesizers."
This suggested that the filter was going to be the Korg35-based one, and was backed up by pictures of the innards from early purchasers of the device, here and here, and having now got hold of one, I can confirm this is the case—it follows the Korg35 topology fairly closely, with detail changes for biasing and exponential control etc., as one would expect, due to the limitations of the 5V supply. In the spirit of saving others following having to do the same leg-work, chips identified so far are:
LM324 op amps—obvious!
TPA6111A2 audio amp
SN74AHC14 hex Schmitt trigger
NPN transistors, 'BR', 2SC5658
PNP transistors, 'FR', 2SA2029
Large SOT-23 transistors, marked 'KC'—suspect they are N-channel JFETs, but no decent id on them as yet
Diodes, 'A' 1SS355
Dual NPN transistors, 'X9', IMX9
DC-DC boost converter, 'AUJ' TPS61070