DT GCSE Project by Oscar Jones

Speaker inside

This speaker was created for my GCSE Electronics project, completed over the course of about a year. It was made completely from scratch, with the amplifier design from an amplifier construction book photocopied onto acetate and etched onto PCB, and all the 80+ discrete components soldered on by myself. The amplifier was powered by a +/- 42V 5A power supply, and was rated for 200 Watts. The construction process of the electronics was long, with the board taking about two weeks to finish, then some further time securing it to the heat sink with bolts through cut and bent aluminum strips.
The power and audio inputs and power outputs where soldered to the board, and the necessary input components mounted to the enclosure. The enclosure consisted of a laser cut plywood front and back, with the front layered up to effectively countersink the speaker drivers. The curved shell is two layers of flexiply, all glued together. The back panel is also multiple layers, the inner most slightly smaller to allow the back to fit into the shell like a plug. The front is the same, however was never fixed to the shell, as access was needed to the inside to assess the project. The speakers are simply bolted in place, with some grey tape used to give the subwoofers an air tight seal. Speaker back
Speaker box front The speakers used were two 6-1/2″ subwoofers and two 4″ full range drivers, with a 100Hz crossover network. The system did indeed work, and I achieved a grade of 100% for this coursework part of the DT GCSE. After this though the performance of the amplifier board deteriorated, and I removed the speakers to be used elsewhere as I am yet to fix the board. My suspicions are that one or more components may have burnt out. However, the unit still sits proudly in my room. Speaker front