HardLabs

BiasPro

ToneAlchemy·BiasPro·HARDWARE - PCB KICAD/BiasPro - KICAD/Kicad - Bias_Meter - Project Files/BiasPro_InputProtection_v3.kicad_pcb

BiasPro PCB layout, top view — open source AVR/Arduino board by ToneAlchemy

About the BiasPro PCB

BiasPro is an open source AVR/Arduino PCB design by ToneAlchemy, published on GitHub under the MIT license. It is a 2-layer board measuring 33.9 × 90 mm, with 18 components from 15 distinct parts.

Its main chip is the Arduino Nano v3, from the AVR/Arduino family. Other key parts include the ADS1115 and A - PROBE. By type, the board carries 3 switches, 2 modules and 1 IC.

It belongs with the audio designs in this gallery.

From the project

A professional-grade, dual-probe Arduino Bias Meter for guitar tube amplifiers. Open source hardware & firmware

This repository contains the complete, mathematically hardened firmware for a professional-grade, dual-probe vacuum tube BiasPro. Designed for guitar amplifier technicians, this tool provides real-time, high-resolution measurements of Plate Voltage, Cathode Current, and True Plate Dissipation (Watts & %) for power tubes (e.g., 6L6GC, EL34, 6V6, KT88).

This firmware was completely re-architected from scratch using modern, memory-safe embedded C++ principles to eliminate dynamic memory leaks and ensure rock-solid physical safety lockouts.

BiasPro, from the project README
From the project README

Main components on the BiasPro

ADS1115Arduino Nano v3A - PROBE

BiasPro bill of materials (BOM)

18 components, 15 distinct parts.

QtyPartRefs
1
ADS1115
U1
1
Arduino Nano v3
A0
1
A - PROBE
A1
1
B - PROBE
B1
4
1N4733A
DZA0, DZA1, DZA2, DZA3
1
GND
O1
1
SCL
O2
1
SDA
O3
1
CS
O4
1
DC
O5
1
RES
O6
1
VCC
O7
1
L
SW1
1
R
SW2
1
C
SW3

BiasPro design files

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

BiasPro: common questions

What microcontroller does the BiasPro use?

The BiasPro is built around the Arduino Nano v3, from the AVR/Arduino family.

How big is the BiasPro PCB?

The BiasPro measures 33.9 × 90 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the BiasPro?

18 components, from 15 distinct parts. The full bill of materials is listed on this page.

Where can I download the BiasPro design files?

From the ToneAlchemy/BiasPro repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the BiasPro design in my own project?

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

Can I test firmware for the BiasPro 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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