2 layers66.6 × 100 mm Logic pcb, the printed circuit board in 3D

Logic pcb

A collection of free & open source DIY synthesizer module designs for Eurorack

Size: 66.6 × 100 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 76
Nets: 70
Pads: 239
Tracks, vias: 568, 36
Pours: 2
Routed: Yes
KiCad: KiCad 9.0 (file 20241229)
Created: 17 Dec 2019
Updated: 3 Nov 2026

Overview

Logic pcb is an open-source printed circuit board by QuinnFreedman, from the QuinnFreedman/modular repository on GitHub. It is a 2-layer board of 66.6 × 100 mm with 76 parts on 70 nets, routed with 568 tracks and 36 vias.

It is built around the LM324, TL072 and CD74HCT132E, with the LM4040C50FTA among its other parts. Its parts include 32 resistors, 17 connectors, 15 capacitors, 6 ICs and 3 diodes. It belongs with the audio and music boards of this library.

Main components

README

README.md

This project is an attempt to make Eurorack modular synthesis affordable and accessible to everyone.

This repository contains open source software and hardware schematics for Eurorack modules which are designed to be assembled easily and cheaply without any technical knowledge. Every module should be able to be assembled for around $20 in about an hour of work, even with limited experience.

To get started, check out some of the links below. Or get in touch! Send me a message at freemodular@gmail.com. Follow my reddit, Etsy shop, or GitHub.

Happy travels on your modular journey!

Go to the website to see more

Modules

{% include_relative docs/modules.md %}

Parts

Qty	Value	Footprint	References
18	10kΩ	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R1, R2, R6, R10, R11, R12, R13, R15, R19, R20, R21, R22, R23, R24, R25, R26 +2
12	THONKICONN	FreeModular:THONKICONN	J1, J2, J3, J4, J5, J6, J7, J8, J9, J10, J11, J12
9	100nF	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C8, C9, C10, C11, C12, C13, C14, C15, C16
6	1kΩ	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R14, R17, R18, R27, R28, R29
4	330pF	Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder	C1, C2, C3, C4
4	5.1kΩ	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R3, R4, R5, R8
3	100kΩ	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R16, R31, R32
3	1N4148	Diode_SMD:D_SOD-123	D1, D2, D3
2	10uF	Capacitor_SMD:CP_Elec_4x5.4	C5, C6
2	Board	kikit:Board	B1, B2
2	CD74HCT132E	Package_SO:SOIC-14_3.9x8.7mm_P1.27mm	U1, U2
2	LM324	Package_SO:SOIC-14_3.9x8.7mm_P1.27mm	U3, U4
1	3.3kΩ	Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder	R30
1	Conn_01x06_Pin	Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical	J17
1	Conn_01x06_Socket	Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical	J16
1	Conn_01x07_Pin	Connector_PinSocket_2.54mm:PinSocket_1x07_P2.54mm_Vertical	J14
1	Conn_01x07_Socket	Connector_PinSocket_2.54mm:PinSocket_1x07_P2.54mm_Vertical	J15
1	Eurorack_2x5_Power	Connector_IDC:IDC-Header_2x05_P2.54mm_Vertical	J13
1	LM4040C50FTA	Package_TO_SOT_SMD:SOT-23	U6
1	TL072	Package_SO:SOP-8_3.9x4.9mm_P1.27mm	U5
1	logo_very_small	FreeModular:logo_very_small	G1

Questions

How big is the Logic pcb PCB?

It measures 66.6 × 100 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Logic pcb use?

76 parts, built around the LM324, TL072, CD74HCT132E and LM4040C50FTA. 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 Logic pcb KiCad files?

From the QuinnFreedman/modular repository on GitHub, at the commit this page was made from: the board is modules/Logic/PCBs/logic_pcb/logic_pcb.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.

Can I use the Logic pcb design in my own project?

Its repository states no licence, so its author keeps all rights: ask QuinnFreedman before reusing the design.

Category and platform

Audio and music

Topics

eurorack music modular

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/quinnfreedman-modular-logic-pcb" title="Logic pcb in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/quinnfreedman-modular-logic-pcb.jpg" alt="Logic pcb" width="1200" height="900">

A picture that opens the board, for a README

[![Logic pcb](https://pcbkit.io/embed/boards/quinnfreedman-modular-logic-pcb.jpg?size=s)](https://pcbkit.io/boards/quinnfreedman-modular-logic-pcb)

Source

Repository: QuinnFreedman/modular
Board file: modules/Logic/PCBs/logic_pcb/logic_pcb.kicad_pcb
Commit: c78d208
Homepage: freemodular.org
Licence: Not stated

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