4 layers65.8 × 128.5 mm
2 layers45.1 × 102.5 mm
Experimental Eurorack Synth DIY Project
- Size
- 45.1 × 102.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 68
- Nets
- 48
- Pads
- 200
- Tracks, vias
- 338, 30
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 15 Aug 2019
- Updated
- 18 May 2025
Overview
Osc1 is an open-source printed circuit board by jomag, from the jomag/synth-project repository on GitHub. It is a 2-layer board of 45.1 × 102.5 mm with 68 parts on 48 nets, routed with 338 tracks and 30 vias.
It is built around the TL072. Its parts include 35 resistors, 12 capacitors, 10 connectors, 4 ICs and 2 diodes. It belongs with the audio and music boards of this library.
Main components
1README
README.mdProject files for an experimental, DIY modular synth in Eurorack format.
Casing
Threaded strips: 2x5x432 mm (also available in 203.2 mm). Hole distance: 5.08 mm.
https://gie-tec.de/product/threaded-strips/?lang=en
References
A lot of generic and module specific design tips: http://dintree.com/
Precision tuning of the AS3340 VCO https://cabintechglobal.com/tune3340 http://www.alfarzpp.lv/eng/sc/Tuning%20the%20AS3340.pdf
CEM3340 VCO (Voltage Controlled Oscillator) designs https://electricdruid.net/cem3340-vco-voltage-controlled-oscillator-designs/
Kassutronics blog: VCO CEM3340: https://kassu2000.blogspot.com/2018/06/vco-3340.html
Collection of a few simple Eurorack module PCB and some notes about components etc: https://github.com/nickajeglin/Eurorack-pcbs
Understanding audio jack switches https://www.cuidevices.com/blog/understanding-audio-jack-switches-and-schematic
Timo Rozendal CEM3340 VCO design http://www.timorozendal.com/files/cem3340vco_schematic.pdfs
Parts
68| Qty | Value | Footprint | References |
|---|---|---|---|
| 7 | 10k | Resistor_SMD:R_0603_1608Metric | R4, R5, R17, R18, R20, R22, R23 |
| 4 | 0.1u | Capacitor_SMD:C_0603_1608Metric | C1, C7, C8, C12 |
| 4 | 1n | Capacitor_SMD:C_0603_1608Metric | C2, C3, C5, C6 |
| 3 | 0? | Resistor_SMD:R_0603_1608Metric | R30, R31, R32 |
| 3 | 1M | Resistor_SMD:R_0603_1608Metric | R3, R33, R35 |
| 3 | 3k | Resistor_SMD:R_0603_1608Metric | R25, R27, R29 |
| 2 | 1.5M | Resistor_SMD:R_0603_1608Metric | R9, R14 |
| 2 | 100k | Potentiometer_THT:Potentiometer_Alpha_RD901F-40-00D_Single_Vertical_CircularHoles | RV1, RV4 |
| 2 | 100k | Resistor_SMD:R_0603_1608Metric | R2, R6 |
| 2 | 10n | Capacitor_SMD:C_0603_1608Metric | C4, C11 |
| 2 | 1N914 | Diode_SMD:D_SOD-523 | D1, D2 |
| 2 | 1k5 | Resistor_SMD:R_0603_1608Metric | R24, R26 |
| 2 | 1k8 | Resistor_SMD:R_0603_1608Metric | R13, R28 |
| 2 | 1u | Capacitor_SMD:C_0603_1608Metric | C9, C10 |
| 2 | 470 | Resistor_SMD:R_0603_1608Metric | R10, R34 |
| 2 | TL072 | Package_SO:SO-8_3.9x4.9mm_P1.27mm | U2, U3 |
| 1 | 10k | Potentiometer_THT:Potentiometer_Bourns_3296W_Vertical | RV5 |
| 1 | 10k | Potentiometer_THT:Potentiometer_Alpha_RD901F-40-00D_Single_Vertical_CircularHoles | RV2 |
| 1 | 150k | Resistor_SMD:R_0603_1608Metric | R1 |
| 1 | 15k | Resistor_SMD:R_0603_1608Metric | R21 |
| 1 | 20k | Resistor_SMD:R_0603_1608Metric | R19 |
| 1 | 20k | Potentiometer_THT:Potentiometer_Bourns_3296W_Vertical | RV3 |
| 1 | 220k | Resistor_SMD:R_0603_1608Metric | R7 |
| 1 | 24k | Resistor_SMD:R_0603_1608Metric | R11 |
| 1 | 30k | Resistor_SMD:R_0603_1608Metric | R16 |
| 1 | 47k | Resistor_SMD:R_0603_1608Metric | R8 |
| 1 | 5.6k | Resistor_SMD:R_0603_1608Metric | R12 |
| 1 | 51k | Resistor_SMD:R_0603_1608Metric | R15 |
| 1 | AS3340 | Package_DIP:DIP-16_W7.62mm_Socket | U1 |
| 1 | Conn_02x08_Odd_Even | Connector_IDC:IDC-Header_2x08_P2.54mm_Vertical | J6 |
| 1 | Hard Sync + | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J2 |
| 1 | Hard Sync - | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J3 |
| 1 | L79L05_SOT89 | Package_TO_SOT_SMD:SOT-89-3 | U4 |
| 1 | LinFM | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J1 |
| 1 | PWMControl | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J10 |
| 1 | Saw Wave Output | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J9 |
| 1 | Soft Sync Input | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J5 |
| 1 | Square Wave Output | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J8 |
| 1 | Triangular Wave Output | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J7 |
| 1 | VOct | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | J4 |
Questions
How big is the Osc1 PCB?
It measures 45.1 × 102.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Osc1 use?
68 parts, built around the TL072. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Osc1 KiCad files?
From the jomag/synth-project repository on GitHub, at the commit this page was made from: the board is osc1/osc1.kicad_pcb and its schematic midi/rev0/don-midi2cv.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Osc1 design in my own project?
Its repository states no licence, so its author keeps all rights: ask jomag before reusing the design.
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