ePortfolio: Personal Projects



Valve amplifier

Laser tube, showing water cooling tubes

Initial build

The first amplifier was a clone of a Marshall 18W valve amplifier made as a gift.

1st Prototype

This is an improved version with the amplifier designed to produce less “hum” in the speaker and increase the amount of distortion available.

2nd Prototype

A variation of the above design, with added tone control and higher power output.

3rd Prototype

From the building of the previous three designs, this amplifier has been built. It has reduced hum, higher power, gain control and bass, middle and treble tone controls.

Circuit redesign, improving performance. From here I am going to design a printed circuit board version.

Speaker cabinet manufactured from finger jointed plywood with fabric grill and green vinyl covering.

Carbon Dioxide Laser Cutter


X-axis belt

Y-axis belt

Mirror and focussing lens

Laser tube

X-Axis stepper motor

Laser head assembly

Timing belt tensioner

The prototype

The result of the first run

The optical system

The tube operating for the first time

Mach 3 software controlling the stepper motors and laser power

A chassis manufactured from box formed mild steel and laser cut acrylic front and back panels

This laser cutter was designed and built from scratch. It was a very challenging project, involving the component parts below:

Optical system

One fixed mirror and two moving mirrors to direct laser beam onto surface, laser focussing lens, CO2 laser tube. Water cooling pump.

Drive system

Timing belt driven X and Y laser head positioning using timing belts driven by stepper motors


Stepper motor control circuit, laser power control circuit an high voltage power supply


Aluminium frame, linear bearings, timing belts.

Cooling system

Water pumped through outer envelope of laser tube to prevent overheating.

This project started after I built a copy of a Marshall 18W valve amplifier. Once I completed it I decided to develop my own designs, using vintage technology. It has required me to learn new skills in an area of electronics I previously had no knowledge. It has required the use of woodworking and metal working skills and the use of a laser cutter to mark out the chassis and fabricate the front and rear panels.

I am now continuing to improve my designs.

Thermoelectric Generator

During my studies for my first degree I was required to complete a self directed design and manufacture project. With an interest in renewable and alternative electricity generation I decided to investigate a method of producing electricity in remote locations, such as when camping.

My first thoughts were to investigate how the waste heat from a camping kettle or pan could be used to generate electricity to power lighting or to charge mobile phones. The device I designed could also store the power generated in “Ultra Capacitors” rather than traditional rechargeable batteries.

The project was featured in the Technology Enhancement Programme’s magazine “News and Views”, showcasing projects developed by students at Sheffield Hallam University.

Valve Amplifier

Laser cut mounting brackets