Sure, that would work . ?
You will need about 5A at 20V to make full output.?
I used a Meanwell 110V to 24, modified it to 20V out, and put the 78l05 in a glob of tape inside the amp.
Hans’ document says 20V but I have heard of slightly higher. I stuck with 20V or less.?
Larry
KB3CUF?
Playing around with this idea a bit, I think what I'm going to do is get a voltage booster, and put it in a small separate device.? On that device I'll do an RCA PTT jack from the radio, put the 78L05 regulator in that case tapped off the 12v input, and then the +5v output to the amp.? That way the amp can remain 'stock', and I have another small companion device that will stay with it to boost the voltage to 22v, and provide the +5vdc keying signal.
