Q1 is a Rohm IMX9, eminently obtanium via Mouser and Digi-Key:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=IMX9T110CT-ND

The IMX9 was probably used as a cheap way to get a matched and/or thermally coupled transistor pair, although there’s no mention of matching in the datasheet.

You could trade circuitry for code, but I think that misses all the appeal of the Monotron.

I’m very interested in making my own synth but after looking at the schematics I can tell I’m too stupid to get this

@Digital HaD also has a nice section in the howto tutorials on a pretty simple one. I found the MFOS and it’s junky-crazy webpage to just be too annoying. Ray Wilson is a bit of an asshole. The atari punk console is another easy project to start with. Ya can even google up some radioshack electronic kit videos in which people have done some pretty impressive stuff. Analog Box is a fun piece of software to design circuits with tons of bleep/drone modules made by users. Happy building :)

I love my little monotron. I’m getting a second one for my b-day to actually crack open and tinker with. Like most say, it is worth it for the filter alone. And it looks like the devs were super nice about making it tinker-friendly from what I’ve seen which is awesome :)

If you’re new to analog circuitry, don’t even think of trying to build this thing all from scratch at once using only a circuit as a reference. Build simple modules one by one, see how they work first, then join them together.

@Digitalundernet instead of the traditional (read: expensive) analogue synth, you could consider starting with Lunetta’s. They have synth-like characteristics but are much more glitchy and lo-fi. Kind of a step up from the Atari Punk Console. Eminently engaging fun and super cheap. More info: http://electro-music.com/forum/index.php?f=160

Wanna beat thomas dolby at his own game? Check out the japanese equivalent of PAIA – Gakken. Except they come pre-assembled.

PAIA… great guy[z], legendary, amazing company… but basically the entire product line should have been rendered to silicon years ago. Bring back the jolt, and get us synthetic patch cords so we can change configs on the fly. The newest products are basically 20 years old. I like classics, but there’s a world of new users out there who want and need features like sampling and cascading reverb units with multiple taps.

Come on PAIA, you can do it! Give us the weird CV analog synth equivalent of a quad rack setup using surface mount components in a bento-box form factor! Give us an eeprom that will save patches… we know you’re not dead yet!

oh wow I didn’t even know this synth existed. YES!!!

Note that there are multiple connections to the “Bias” net generated by IC2B (text search the PDF). This is a floating virtual ground enabling the use of single supply rail op amps.

The little triangle is not ground! ;)

J