2 layers70 × 35 mm
2 layers190 × 83.8 mm
Audio Synthesizer
JH-2108/Custom-Audio-SynthesizerA low cost RP2040-based audio synthesizer, featuring eight playable, rotary encoders, sound controls, a built-in speaker, custom PCB designing, and a compact enclosure.
- Size
- 190 × 83.8 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 41
- Nets
- 53
- Pads
- 165
- Tracks, vias
- 327, 37
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 18 Oct 2026
- Updated
- 26 Oct 2026
Overview
Audio Synthesizer is an open-source printed circuit board by JH-2108, from the JH-2108/Custom-Audio-Synthesizer repository on GitHub. It is a 2-layer board of 190 × 83.8 mm with 41 parts on 53 nets, routed with 327 tracks and 37 vias.
Its parts include 18 switches, 16 diodes, 4 connectors and 2 capacitors. It belongs with the audio and music boards of this library.
README
README.mdCustom-Audio-Synthesizer-
This custom audio synthesizer is a custom made, compact, standalone chiptune synthesizer built around an RP2040 development board. It allows users to create simple electronic melodies using eight playable keys, function buttons, and rotary encoders.
The project combines embedded programming, basic audio electronics, PCB design, and enclosure design into a small musical instrument.
Features
- Eight playable keys for generating musical notes.
- Octave controls to change the pitch range.
- Sound mode selection for different synthesized tones.
- Two rotary encoders for adjusting sound parameters.
- Build-in speaker driven by an audio amplifier.
- RP2040-based control system
- Custom PCB and compact enclosure.
Project goals
The goal of this custom audio synthesizer project is to build and design an affordable, portable electronic instrument that demonstrates how a microcontroller can generate sound and respond to physical controls.
The project focuses on keeping the design compact, minimizing component costs and making the hardware understandable and reproducible.
Planned controls
| Control | Function |
|---|---|
| Eight note keys | Play individual notes |
| Octave-up button | Increase the playable pitch range |
| Octave-down button | Decrease the playable pitch range |
| Mode button | Change the sound mode |
| Encoder 1 | Select sound settings or waveform |
| Encoder 2 | Adjust an additional sound parameter |
Sound generation
The RP2040 will generate digital audio using programmed waveforms. The audio signal will be sent to an amplifier, which drives the built-in speaker.
Planned sound modes include square-wave tones, alternative synthesized waveforms, and simple arpeggiator effects, depending on the final firmware.
Project pictures
PCB design
Schematics
3d rendered PCB
CAD model version
Parts
41| Qty | Value | Footprint | References |
|---|---|---|---|
| 16 | 1N4148 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12, D13, D14, D15, D16 |
| 16 | SW_Push | Button_Switch_THT:SW_PUSH_6mm | SW1, SW2, SW3, SW4, SW5, SW6, SW7, SW8, SW9, SW10, SW11, SW12, SW13, SW14, SW15, SW16 |
| 2 | Conn_01x20 | Connector_PinSocket_2.54mm:PinSocket_1x20_P2.54mm_Vertical | J1, J4 |
| 2 | RotaryEncoder_Switch | Rotary_Encoder:RotaryEncoder_Alps_EC11E-Switch_Vertical_H20mm | SW17, SW18 |
| 1 | 100nF | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C1 |
| 1 | 10uF | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C2 |
| 1 | Conn_01x02 | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J3 |
| 1 | Conn_01x05 | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J2 |
| 1 | SSD1306 | SSD1306:128x64OLED | Brd1 |
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Questions
How big is the Audio Synthesizer PCB?
It measures 190 × 83.8 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Audio Synthesizer use?
41 parts. 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 Audio Synthesizer KiCad files?
From the JH-2108/Custom-Audio-Synthesizer repository on GitHub, at the commit this page was made from: the board is PCB/Audio Synthesizer.kicad_pcb and its schematic PCB/Audio Synthesizer.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Audio Synthesizer design in my own project?
Its repository states no licence, so its author keeps all rights: ask JH-2108 before reusing the design.