Hi-Fi Preamp :

The aim of this project was to add remote-control convenience to the hi-fi without compromising sound quality. I considered simply replacing the existing volume control in my Musical Fidelity A1 with a motorised version, but keeping the unit separate has allowed me to start thinking about building a replacement for the A1.

Update: 30/11/2002: Preamp FAQ - due to the interest this project has generated, I've started an FAQ page... If you've got questions about the preamp, please check it out!

Project Status:

The project is essentially complete - complete details and pictures of the various PCB's have been posted. NEW: PDF versions of the complete schematics are available for easier printing. 17/11/2002: Graphics VFD module installed. Still need to finish the firmware and label the rear panel. The preamp has been in use since December 2002...

17 November, 2002: New Graphic VFD - also, the front panel has been finished and labelled...	26 August, 2002: All PCB's complete and tested, and the metalwork has been drilled. Just need to finish and label the front and rear panels.

Introduction:

• Overview of the preamp and its facilities
• User interface: explains how the various options work, complete with screen-shots...

Technical details:

• Analogue stages - detailing the main audio signal path and the RIAA phono preamp
• Control hardware - the display, PIC PCB and front panel switches, etc.
• Power supply and mechanical details - all the small details...

Full Schematics:

Please note - these schematics are designed to be printed at 300dpi onto A4 paper in landscape mode - use a graphics package for this. They also look pretty good when enlarged to A3 on a photocopier.

• Main analogue schematic
• Surround module schematic
• Phono stage schematic
• Power supply and control schematic

Research:

How the project evolved over the years...

• Initial plans - starting in 1998 as a simple stereo preamp, the need for multichannel, learning PIC programming...
• Analogue research - as electronic volume control was required, a quick survey of the available IC's

Coming soon:

• Conclusions, results of listening tests, more pictures and possibly sections on the firmware - maybe even a user-manual!

Links to similar projects:

Has this project inspired you to build something similar? If so, please let me know and I'll link to it from here...

• Krzysztof Marcinek's 7.1 Preamp
  A multichannel preamp which incorporates a USB DAC.
   
• Suzy Jackson's Preamp
  A two-channel PGA2310 preamp. Check out the PCB's which are neatly laid out using surface-mount components and professionally produced...
   
• Daniel Clark's 7.1 Preamp
  An excellent example of the PGA2310 in a multichannel preamp...
   
• Devil_H@ck's WM8816-based Preamp
  An interesting looking project that incorporates many similar features...