One of the good things about Christmas is that I always managed to get some proper time for working on my projects. This year is devoted to my belated project: 4-65A SE amplifier. We bid farewell to our family guests so had this evening a bit of time to start preparing the filament raw supply for the 4-65A.
This will be a heavyweight amplifier. Too much iron, but 100% DHT and no capacitor in the signal path, a promising design.
A couple of hours were sufficient to prepare some of the key components: a pair of common-mode chokes winded on ferrite rings, capacitor arrays and a Schottky bridge mounted on an aluminium sink:
The raw filament supply circuit follows the standard design recommended by Rod Coleman to use the filament regulator boards. I managed to get a nice pair of [email protected] chokes made by JMS transformers which is the same company that provides the custom-made split bobbin transformers:
The 10mH choke will help reducing the current pulses and the input capacitance, which is less than 3mF. This circuit will provide 12V @ 3.5A with a ripple current of 31mV peak to peak maximum.