Build pictures

Transistors tanning. Notice how this heatsink has been through a lot…lots of holes.

First tests, including cooling:

Preparing to put things together:

First test. The front panel is 3D printed. Also the knob, I did not have one for perfectly cylindrical shaft multi-turn potentiometer.

Testing the power brick guilty of burning the previous transistors. After a long time, the heatsink reached about 45°C in the middle at the well cooled area and 53°C at the edge fins where there is not much air flow.

And finally testing the speed using a 7805 regulator and short output wires using a 10kHz, 1A load. The rise and fall time are about 2.1µs.