An extreme MONOTRON mod by Soul Machine in form of an SMD PCB.
The schematics design and build instructions were published by Soul Machine on his project page Far Beyond Perception Instruments and as PDF here.
He built it with a lot of perf board and freehand wiring.
Also special thanks to Heiner Büge who convinced me to build this mod with him. He also brought a lot of knowledge about analog synthesizers into this project and I would not have been able to develop this project without him!
This project aims to take the design of Soul Machine and develop a neat printed circuit board with SMD components where sensible so that it can be produced and to a large degree even be assembled by cheap manufacturers like JLCPCB or PCBWay.
0805 chip resistors with 1% tolerance shall be used for relatively easy hand soldering. Most capacitors are cermaic 0805. 100uF (10V) and 47uF (6V3) use 1206 package instead.
| Part | Count | Refs | JLCPCB # extended (2021-08-27) |
|---|---|---|---|
| 100uF | 3 | C201, C303, C403 | C312983 |
| 10uF | 10 | C202, C205-C207, C308, C401, C402, C506, C601, C702 | C15850 |
| 47uF | 2 | C203, C204 | C96123 |
| 1uF | 5 | C301, C302, C304, C305, C701 | C28323 |
| 100nF | 7 | C306, C501, C505, C507-C510 | C49678 |
| 470nF | 1 | C307 | C13967 |
| 22pF | 1 | C309 | C1804 |
| 500pF | 1 | C404 | C1747 |
| 47nF | 1 | C502 | C53134 |
| 4.7nF | 1 | C503 | C1744 |
| 470pF | 1 | C504 | C1743 |
| 100pF | 1 | C703 | C1790 |
| 1N4148 | 4 | D301, D302, D401, D402 | C2128 |
| 2SC945 | 1 | Q701 | C181154 |
| 10k | 22 | R201, R202, R417, R501, R505-R507, R509, R510, R512, R513, R515, R516, R518, R519, R521, R522, R524, R604, R607, R608, R610 | C17414 |
| 100k | 43 | R301-R305, R307, R309-R312, R318, R324-R331, R401, R402, R404, R406-R413, R420, R421, R502, R602, R609, R612-R614, R616, R701-R703, R706 | C149504 |
| 33k | 1 | R306 | C17633 |
| 47 | 1 | R308 | C17714 |
| 5k6 | 2 | R313, R321 | C4382 |
| 4k7 | 1 | R314 | C17673 |
| 1M | 4 | R315, R322, R403, R503 | C17514 |
| 47k | 2 | R316, R618 | C17713 |
| 56k | 1 | R317 | C17756 |
| 12 | 1 | R319 | C204200 |
| 39k | 2 | R320, R419 | C25826 |
| 220k | 1 | R323 | C17556 |
| 22k | 1 | R405 | C17560 |
| 2k2 | 3 | R414-R416 | C17520 |
| 180 | 2 | R418, R504 | C25270 |
| 1k | 11 | R508, R511, R514, R517, R520, R523, R525, R601, R605, R619, R707 | C17513 |
| 56 | 1 | R603 | C17757 |
| 390 | 1 | R606 | C17655 |
| 27k | 1 | R611 | C17593 |
| 330k | 1 | R615 | C17629 |
| 68k | 1 | R617 | C17801 |
| 680k | 1 | R704 | C17797 |
| 470k | 1 | R705 | C17709 |
| 150k | 1 | R708 | C17470 |
| AMS1117-5.0 | 1 | U202 | C6187 |
| LMV321 | 3 | U203, U304, U501 | C7972 |
| ICL7660S | 1 | U204 | C7535 |
| LM324 | 4 | U301, U302, U401, U402 | C71035 |
| CD4040BM/TR | 1 | U303 | C725347 |
| TL082 | 3 | U601, U602, U701 | C9385 |
| Part | Count | Refs |
|---|---|---|
| 10k trimmer pot | 5 | RV303, RV401, RV601, RV603, RV605 |
| 100k trimmer pot | 3 | RV502, RV504, RV606 |
| DIP-14 IC socket | 1 | U502 |
| Part | Count | Refs (optional) |
|---|---|---|
| Korg MONOTRON | 1 | J101 |
| LED | 2 | D403, D501 |
| DC jack | 1 | J201 |
| rotary switch 3P4T | 2 | J301, J601 |
| rotary switch 4P3T | 1 | J401 |
| 1/4" mono jack | 3 | J602, J603, J701 |
| 10k pot | 9..11 | RV301, RV501, RV503, (RV505), (RV506), RV507, RV508, RV509, RV510, RV602, RV701 |
| 100k pot | 1 | RV302 |
| 20k pot | 2 | RV402, RV403 |
| 220k pot | 1 | RV604 |
| toggle switch SPST | 1..4 | (SW501), (SW502), SW601, (SW603) |
| mom. switch SPST | 1 | SW605 |
| toggle switch SP3T | 0..1 | (SW503) |
| toggle switch SPDT | 3..4 | (SW504), SW602, SW604, SW701 |
| mom. switch SPDT | 0..1 | (SW505) |
PCB front:
PCB back:
