Circuit Lake

Electronic Project and Circuit Collection

PIC Controlled Hi-Fi Preamp

12/02/2009 Category: Audio, PIC, Project


The aim of this project was to add remote-control convenience to the hi-fi preamp without compromising sound quality. It replacing the existing volume control with high-quality optical rotary encoder controlled by PIC 16F877. The project has 7 input sources and 5.1 surround sound.


  • High quality, clear and easy to read VF display.
  • Volume control is a high-quality optical rotary encoder.
  • Intuitive operation – all day-to-day functions are simple single keypresses.
  • Simple menu operation of less-used functions like Record-Out or surround level adjustment.
  • Scrolling helptext for menu operation.
  • Control of surround channel levels and a per-input option to send a L+R mix to the LFE output, enabling easy use of a sub-woofer for music sources. For each input that this option is enabled, the level is adjustable. For example, you could choose a lower level for the phono input to avoid problems caused by warped records or acoustic feedback.
  • Full remote control of all functions. Philips RC-5 protocol (responds to some CD player remote controls).

© Mark Hennessy

Hi-Fi Preamp
Project Documentation And Schematic