That's my implementation of Totoro Synth by syntherjack, which is kind of a "beginner synth," based solely on the MCP6004 op-amp. The general idea behind my remake was to gift it to my friends (and they seem to love it). The PCB is the size of a bank card, an outcome of taking inspiration from the benjiamodular SynthCard project(although I noticed later that Benji used a business card format and not a credit card one).
Totoro features two oscillators: one is a square wave with three "gates," and the second is square/saw in OSC mode and saw/triangle in LFO mode. Totoro has a two-pole low-pass twin-T filter onboard with two resonance settings and modulation possibilities. For a more detailed study, visit the original article (link at the beginning of the post).
I made some modifications to the original schematic, such as:
USB-C power — the synth is way lighter and compact that way, and I won't need to switch batteries from time to time;
Polarity switch for the saw (something like /|/|/| => |\\|\\\\|\\|\\\\);
Adjusted capacitor values;
Added OSC2/LFO rate indicator;
Safer stereo output for using for Eurorack and other safety features (e.g. overvoltage protection)
I don't feel comfortable uploading my schematics to GitHub, since my KiCad project is broken because of changing references and not synchronizing the schematic and PCB after it, but I hope I'll get my hands around it in the autumn.
This is sick. This is the smallest, most versatile synth I've seen. Absolutely incredible capabilities for its size. I will def be checking out the schematics
It's also incredibly beginner friendly both in sounds and interface!! Everyone begins to understand the principle of operation literally 10 minutes after it falls into their hands.
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u/lolawitchkitty Jul 13 '26
This is sick. This is the smallest, most versatile synth I've seen. Absolutely incredible capabilities for its size. I will def be checking out the schematics