2 layers37 × 20.5 mm Buffer, the printed circuit board in 3D

Buffer

This is a DIY multieffects project with a Raspberry Pi and and Codec Zero and a Raspberry Pi Display 2. With Full NAM A2 support.

Open in PCBKit

Size: 37 × 20.5 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 28
Nets: 15
Pads: 57
Tracks, vias: 70, 0
Pours: 1
Routed: Yes
KiCad: KiCad 9.0 (file 20241229)
Created: 9 Jul 2026
Updated: 5 Nov 2026

Overview

Buffer is an open-source printed circuit board by balazsbencs, from the balazsbencs/ardor repository on GitHub, published under the MIT licence. It is a 2-layer board of 37 × 20.5 mm with 28 parts on 15 nets, routed with 70 tracks and 0 vias.

It is built around the TL072, AMS1117-5.0 and SS14. Its parts include 10 capacitors, 8 resistors, 2 ICs and 1 diode.

Main components

README

hardware/ardor-modules-tht/mixer/README.md

Stereo buffer / mono average / AC outputs / HAND ASSEMBLY

T1.1 compact hand-assembly PCB: 70 × 48 mm. Unbuilt engineering prototype.

KiCad project · Manual BOM · Schematic · Bare-board Gerbers

Supply 5 V / 10 mA. Fit MCP6022-I/P DIP-8 amplifiers; TLV9002 SOIC parts from M1 do not fit. Use Nichicon UES1H100MPM, 10 µF / 50 V bipolar, for C401/C402/C407/C408/C409. The 3.5 mm-pitch footprints reserve the manufacturer's maximum 8.5 mm body diameter; maximum can height is 12.5 mm. Either orientation is valid. C101 and C403 are ordinary polarized radial capacitors, positive on pad 1.

Inputs are line-level, no greater than 1 Vrms per channel. Outputs drive loads of at least 10 kΩ. OUT_MONO is (LEFT + RIGHT) / 2; all three outputs are AC-coupled. Feeding only one channel gives half its amplitude at the mono output. Feed both channels for a full-level mono source. The board is not an instrument preamp or headphone amplifier.

Commission with no signal: check the filtered 5 V rail and about 2.5 V at VREF and the internal buffer outputs. Check near-zero settled DC on the external outputs. Feed separate 1 kHz left/right tones and verify unity stereo buffers, mono averaging and channel separation. Check clipping, noise and oscillation across the audio band. Keep external harnesses short; exposed audio sockets need entry protection.

Connector pin assignments

Directions are relative to this board. Standard header square pads identify pin 1. Read reference and pin numbers from the back silkscreen; mirrored CAD exports are labelled as back views.

J101 — 5V POWER INPUT

Pin	Net	Direction	Connect to
1	+5V	POWER INPUT	Positive output of the matching regulated supply.
2	GND	GROUND	Host or cable ground / 0 V.

J102 — STEREO AUDIO INPUT FROM SOURCE

Pin	Net	Direction	Connect to
1	AUDIO_L	INPUT	DAC/codec left audio output, <=1 Vrms.
2	GND	GROUND	Host or cable ground / 0 V.
3	AUDIO_R	INPUT	DAC/codec right audio output, <=1 Vrms.

J103 — BUFFERED STEREO + MONO AUDIO OUTPUT

Pin	Net	Direction	Connect to
1	OUT_L	OUTPUT	Left line input of another device, >=10k load.
2	GND	GROUND	Host or cable ground / 0 V.
3	OUT_R	OUTPUT	Right line input of another device, >=10k load.
4	OUT_MONO	OUTPUT	Mono line input, >=10k load. Signal is (L+R)/2.

Assembly and files

Fit low-profile axial parts first, then sockets/headers and radial capacitors. Match diode bands, electrolytic polarity and IC notches to the PCB. Install the ICs or ADC breakout last. H1/H2 are 2.2 mm nonplated M2 mounting holes, not electrical terminals. Check enclosure clearance and capacitor/socket height. T1.1 compacts the layouts; hole positions differ from T1 and M1.

Use the manual BOM and the bare-board Gerber/drill ZIP. There is no SMT assembly order. Front silkscreen shows component references; the front fabrication drawing shows package outlines and orientation; use the BOM for values. Back silk includes port functions and pin numbers. Native checks and package manifests are under verification/; they do not replace prototype measurements.

Assembly accessories list sockets, shunts and panel items in addition to the PCB component BOM.

Family guide · Substitution sources · Native validation

Parts

Qty	Value	Footprint	References
3	100k	Resistor_SMD:R_0603_1608Metric	R6, R7, R8
3	1u	Capacitor_SMD:C_0603_1608Metric	C2, C5, C6
2	100nF	Capacitor_SMD:C_0603_1608Metric	C8, C10
2	100u	Capacitor_THT:CP_Radial_D6.3mm_P2.50mm	C7, C12
2	1M	Resistor_SMD:R_0603_1608Metric	R2, R4
1	100R	Resistor_SMD:R_0603_1608Metric	R5
1	100pF	Capacitor_SMD:C_0603_1608Metric	C1
1	1k	Resistor_SMD:R_0603_1608Metric	R1
1	1nF	Capacitor_SMD:C_0603_1608Metric	C3
1	2n2	Capacitor_SMD:C_0603_1608Metric	C4
1	3k3	Resistor_SMD:R_0603_1608Metric	R3
1	5V	Connector_Pin:Pin_D1.0mm_L10.0mm_LooseFit	5V1
1	9V	Connector_Pin:Pin_D1.0mm_L10.0mm_LooseFit	9V1
1	AMS1117-5.0	Package_TO_SOT_SMD:SOT-223-3_TabPin2	U1
1	B_IN	Connector_Pin:Pin_D1.0mm_L10.0mm_LooseFit	BUFFER_IN1
1	B_OUT	Connector_Pin:Pin_D1.0mm_L10.0mm_LooseFit	OUT1
1	GND	Connector_Pin:Pin_D1.0mm_L10.0mm_LooseFit	GND1
1	GUITAR_IN	Connector_Pin:Pin_D1.0mm_L10.0mm_LooseFit	GIN1
1	GUITAR_OUT	Connector_Pin:Pin_D1.0mm_L10.0mm_LooseFit	GOUT1
1	SS14	Diode_SMD:D_SMA	D1
1	TL072	Package_SO:SOIC-8_3.9x4.9mm_P1.27mm	U2

Questions

How big is the Buffer PCB?

It measures 37 × 20.5 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Buffer use?

28 parts, built around the TL072, AMS1117-5.0 and SS14. 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 Buffer KiCad files?

From the balazsbencs/ardor repository on GitHub, at the commit this page was made from: the board is buffer/buffer.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.

Can I use the Buffer design in my own project?

Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/balazsbencs-ardor-buffer" title="Buffer 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/balazsbencs-ardor-buffer.jpg" alt="Buffer" width="1200" height="900">

A picture that opens the board, for a README

[![Buffer](https://pcbkit.io/embed/boards/balazsbencs-ardor-buffer.jpg?size=s)](https://pcbkit.io/boards/balazsbencs-ardor-buffer)

Source

Repository: balazsbencs/ardor
Board file: buffer/buffer.kicad_pcb
Commit: 4acb2f7
Homepage: balazsbencs.github.io/ardor
Licence: MIT

Similar boards

2 layers100 × 83.5 mm
Dual Delay
soggybag/Dual-Delay
Two PT2399 delay lines with a TWIST knob blending self and cross feedback (Super-Freq)
121 parts
2 layers100 × 83.5 mm
Loop Echo
soggybag/Loop-Echo
A single-PT2399 delay with an effects loop in the feedback path: - only the repeats circulate through the loop; - the first echo is clean, and each later echo goes through the external effect again: fuzz degrades, a…
90 parts
2 layers20.3 × 110 mm
4HPico
rheslip/2HPico-Eurorack-Module-Hardware
2HP Eurorack module based on Raspberry Pi Pico 2
73 parts84
2 layers30 × 100 mm
Hagiwo Unison VCO
crankery/Hagiwo-Unison-VCO
Hagiwo Unison VCO
50 parts4MIT
2 layers78.5 × 69 mm
Kicad cpu board smt
matthewcieplak/super-sixteen
Code and schematics for the Super Sixteen Eurorack sequencer
57 parts171
2 layers40 × 110 mm
Fv1 module
niektb/sluisbrinkie-eurorack-published
Published Modules of the Sluisbrinkie project
81 parts34
2 layers19 × 108 mm
Active vactrol vca board
lichen-community-systems/lichen-eurorack-hardware
Hardware designs for eurorack synthesizer modules by Lichen Community Systems
45 parts1
4 layers60 × 100 mm
Dchwebb quadraphone quadraphone breakout panel
oomlout/oomlout_oomp_project_bot_v_2

192 parts