This project introduces a digitally controlled 5.1 channel audio preamplifier system. This amplifier is specifically designed to increase the gain of the multi-channel PC sound cards.

This preamplifier consists of six TL074/TL072 preamplifier stages and PT2258 electronic volume control. The input stage of this preamplifier consists of six TL074/TL072 buffer stages. The PIC16F886 microcontroller manages the PT2258 electronic volume control IC. All the volume levels and menu options are displayed on HD44780, 16×2 character LCD screen.

The provided PCB design contains a preamplifier, buffer stages, digital volume control circuit, driver circuit, and power supply unit.

This preamplifier is an open hardware project. All source codes, KiCAD design files, and compiled binaries are available on the GitHub repository.

The complete documentation of this project is available in the wiki section of the GitHub repository. The PCB Gerber files and compiled binaries are also available in the release section of this repository.

All the content of this project are distributed under the terms of the following license:

• Hardware License: CERN-OHL-W 2.0
• Software License: MIT
• Documentation License: CC BY 4.0