HardLabs

Transistor matcher

rabidaudio·synthesizer·transistor_matcher/transistor_matcher.kicad_pcb

Transistor matcher PCB layout, top view — open source AVR/Arduino board by rabidaudio

About the Transistor matcher PCB

Transistor matcher is an open source AVR/Arduino PCB design by rabidaudio, published on GitHub under the MIT license. It is a 2-layer board, with 14 components from 10 distinct parts.

Its main chip is the Teensy2.0_(Arduino), from the AVR/Arduino family. Other key parts include the AD8223 and LM317_3PinPackage. By type, the board carries 6 resistors, 3 ICs, 2 transistors and 2 switches.

It belongs with the audio designs in this gallery.

From the project

My custom synthesizer work

1. Amplifier - LM13700 - matched-pair PNP exponential converter - CV of 10V -> Gain=1 - CV of Gain=\~0, 6 decades below Gain=1 - allow overdrive to Gain=2 - ideally this would begin to clip - mixdown - mono - full mix -> left and right - stereo split - A+C->left B+D->right - Direct stereo input jack - mix arbitrary signal with mixdown - e.g. for accepting signals from other synths 2. Oscillator - 0-10V, 1V/octave, A0 to A10 - Square/Triangle core via LM13700 - Waveshapper for triangle -> sine - PWM control - triangle wave applied to comparator with CV controlling reference. Triangle wave…

Transistor matcher, from the project README
From the project README

Main components on the Transistor matcher

AD8223LM317_3PinPackageTeensy2.0_(Arduino)

Transistor matcher bill of materials (BOM)

14 components, 10 distinct parts.

QtyPartRefs
1
AD8223
U1
1
LM317_3PinPackage
U2
1
Teensy2.0_(Arduino)
U3
2
2N3904
Q1, Q2
1
50K TRIM
RV1
2
SW_DPDT_x2
SW1, SW2
1
10K
R1
1
100
R3
2
220
R4, R5
2
4K7
R6, R7

Transistor matcher design files

The KiCad project lives in the rabidaudio/synthesizer repository on GitHub; these links point at the commit this page was built from.

Transistor matcher: common questions

What microcontroller does the Transistor matcher use?

The Transistor matcher is built around the Teensy2.0_(Arduino), from the AVR/Arduino family.

How big is the Transistor matcher PCB?

The Transistor matcher has 2 copper layers and is 1.6 mm thick.

How many components are on the Transistor matcher?

14 components, from 10 distinct parts. The full bill of materials is listed on this page.

Where can I download the Transistor matcher design files?

From the rabidaudio/synthesizer repository on GitHub, which has the KiCad layout; the links under Design files point to each one.

Can I use the Transistor matcher design in my own project?

Yes, under the terms of its MIT license, which rabidaudio chose for the repository.

Can I test firmware for the Transistor matcher without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.

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