I have now succesfully done some first tests on the 75V regulator circuit, first piece of the 5V reference circuit, and the Bias voltage circuit (5V reg >> 70, 65, 60, 50 volts). I have been experiencing some issues getting the +-5V clean references to work as well as the +-15V linear regulators, but this should all be fixed in the coming week! See the attatched images for the bias voltage outputs (check out my 3 power supplies haha).

I should be able to soon test the APD next week then begin developing the first PCB for the APD.