- Realtime Analyzing
      - Harmonic Distortion
        Reduction Feedback
      - Adaptive Filtering
      - Chat Program with
      - DIY Speakers
      - Amplifier
      - Preamplifier
      - Wireless Access
      - Wireless Antennas



During my Digital Projects Lab, the professor recommended I find a way to include more circuit level work into my project.  To fulfill this, I decided to build a nice preamplifier which would include an IR remote control to replace the one I had built previous.  The previous preamp I had made worked well but it was not aesthetics pleasing and was built on breadboard rather than a PCB board.

The entire preamplifier circuitry was designed from the ground up by myself.  The PCB boards were also created by myself using a laser printer and Toner Transfer Paper.

Below are pictures, diagrams, and PCB board layouts.

Basic schematic of the preamp

Preamplifier PCB
This picture is of the preamplifier unit as it looks when designed in ExpressPCB.

Power and volume control circuit
This picture shows the volume and power controlling circuit as it appears just before printing it out on the Press 'n Peel Blue toner transfer paper. The yellow text provides labeling. The bottom 18 pin dip chip is the micro controller which decodes Sony IR signals, the 14 pin dip chip is an xor gate the two large rectangles are relays, and the smaller rectangles are voltage regulators.  Yes, I understand the text is printed backwards.  It was my first circuit board.

8th order low pass filter
This picture is of the 8th order LPF with an Fc of 90Hz. It shows what the PCB printout looks at the final stage. This is what is sent to the laser printer to be printed on the toner transfer paper.

Picture of the preamp assembled with the top off
On the far left is the power supply.  To the right of that is the power  controlling circuitry on the bottom and the 8th order low pass filter on the top.  Further right is the motor controlling circuit on the bottom and the preamplifier on the top.

Information and content Copyright © David Swiston
Images released under GPL