For this amplifier I used a amplifier board from a tv. The circuit drawings can be found here: Circuit right, Circuit Left, Pcb.
This amplifier needs a DC voltage of 33V. To create this voltage I used a transformer from an old printer, it delivers 21VAC (50VA). I’ve put a rectifier and some caps after the transformer. The case is recycled from an old vcr.
The rectifier + capacitors (7500µF in total):
The speaker terminals:
I wanted a volume control with buttons, so I made this circuit that generates analogue voltages with PWM.
The pcb with the pic on it:
(On the left is a 5V power supply for the pic 30V ==> 15V ==> 5V)
This experimental pcb is not really reliable, so I made an etched pcb of it. When building it in I was a bit to enthusiast so I forgot to take pictures. However I do have the print-layout (which contains a fault at the pull-down resistors). Download pcb lay-out.
As you can see, I left 1 voltage regulator of the board. This is because I found a 15V regulator on the amplifier pcb.
The front panel:
(The panel looks crooked, but that’s just from pasting 2 images together)