https://github.com/polykit/polykit-x-mainboard
Schematics and PCB layout for a mainboard for an 8 voice polyphonic synthesizer
https://github.com/polykit/polykit-x-mainboard
Last synced: 4 months ago
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Schematics and PCB layout for a mainboard for an 8 voice polyphonic synthesizer
- Host: GitHub
- URL: https://github.com/polykit/polykit-x-mainboard
- Owner: polykit
- License: other
- Created: 2023-01-21T22:20:36.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2025-05-09T11:59:34.000Z (about 1 year ago)
- Last Synced: 2026-02-06T13:33:02.096Z (4 months ago)
- Homepage:
- Size: 3.83 MB
- Stars: 22
- Watchers: 2
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
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README
# Polykit X8 Mainboard
_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
## BOM
|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 |
## Tweaks
* If saw/triangle signal is not audible replace R38 with a 220k resistor on the voice cards
## References
https://www.analog.com/media/en/technical-documentation/data-sheets/ad5676.pdf