THIS IS NOT A FINISHED PRODUCT IN ANY WAY AND STILL UNDER HEAVY DEVELOPMENT - USE AT YOUR OWN RISK!
This repository contains Kicad schematics and PCB layout for a main board for a polyphonic synthesizer that is controlled by a micro controller.
Key features:
- 8 voice cards
- 16-bit DAC
- Atmel2560 micro controller
- Eurorack powered
- MIDI input/output
All parameters of the voice cards are controlled by the DAC. That means patches can be stored and recalled.
There is a video playlist on the design process https://makertube.net/w/p/3N2fRjXwT2SfAUv2VkMy3e
Related repositories:
- Voice Card: https://github.com/polykit/polykit-x-voice-card
- Control Board: https://github.com/polykit/polykit-x-controlboard
- Input Board: soon
- Software: soon
- Power Supply: https://github.com/polykit/eurorack-psu
| Reference | Value | Footprint | Qty |
|---|---|---|---|
| C1, C2, C11-C18, C23-C25, C31-C34, C43-C47, C56-C59, C64, C65 | 100n ceramic | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | 28 |
| C3-C10, C19-C22, C26-C29, C35-C42, C48-C55 | 10n film, PPS | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | 32 |
| C30 | 10u | Capacitor_SMD:CP_Elec_5x5.9 | 1 |
| C60-C63 | 100u | Capacitor_SMD:CP_Elec_6.3x7.7 | 4 |
| D1 | 1N4148WS | Diode_SMD:D_SOD-323_HandSoldering | 1 |
| J1 | POWER | Connector_IDC:IDC-Header_2x08_P2.54mm_Vertical | 1 |
| J2 | OUTPUT | Connector_Molex:Molex_KK-254_AE-6410-03A_1x03_P2.54mm_Vertical | 1 |
| J3 | MIDI IN | Connector_Molex:Molex_KK-254_AE-6410-02A_1x02_P2.54mm_Vertical | 1 |
| J4 | MIDI_OUT | Connector_Molex:Molex_KK-254_AE-6410-02A_1x02_P2.54mm_Vertical | 1 |
| J5 | EXTERNAL_IN | Connector_Molex:Molex_KK-254_AE-6410-02A_1x02_P2.54mm_Vertical | 1 |
| J6 | I2C_1 | Connector_IDC:IDC-Header_2x05_P2.54mm_Vertical | 1 |
| J7 | I2C_2 | Connector_IDC:IDC-Header_2x05_P2.54mm_Vertical | 1 |
| J8 | SPI | Connector_IDC:IDC-Header_2x05_P2.54mm_Vertical | 1 |
| J9 | EXT_ANALOG | Connector_IDC:IDC-Header_2x08_P2.54mm_Vertical | 1 |
| J10 | EXT_DIGITAL | Connector_IDC:IDC-Header_2x05_P2.54mm_Vertical | 1 |
| R1-R7, R13-R41 | 100k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | 36 |
| R8, R42, R43 | 1k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | 3 |
| R9-R12, R47 | 10k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | 5 |
| R44-R46 | 220R | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | 3 |
| U1 | Mega2560Pro_Mini | aga:Mega2560Pro_Embed_RobotDyn | 1 |
| U2, U5, U12, U15 | CD4051B | Package_SO:SO-16_5.3x10.2mm_P1.27mm | 4 |
| U3, U4, U6-U8, U13, U14, U16, U17, U19 | TL074 | Package_SO:SO-14_3.9x8.65mm_P1.27mm | 10 |
| U9 | LM4040AIM3-5.0 | Package_TO_SOT_SMD:SOT-23 | 1 |
| U10 | AD5676ARUZ | Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm | 1 |
| U11 | TL072 | Package_SO:SO-8_3.9x4.9mm_P1.27mm | 1 |
| U18 | L7905 | Package_TO_SOT_SMD:TO-263-2 | 1 |
| U20 | 6N137 | Package_DIP:DIP-8_W7.62mm_SMDSocket_SmallPads | 1 |
| VOICE1-VOICE8 | VOICE | Connector_PinSocket_2.54mm:PinSocket_1x36_P2.54mm_Vertical | 8 |
- If saw/triangle signal is not audible replace R38 with a 220k resistor on the voice cards
https://www.analog.com/media/en/technical-documentation/data-sheets/ad5676.pdf