On 1/2/2022 8:53 PM, Waldo Magnuson via ARC5 wrote:
Yes, black wrinkle. Actually it is not a BC-946 but a Navy type CBY-46145, s/n is 1593, so it’s probably an early one.
Skip W7WGM
Then you need the Navy ARA receiver schematic. That's not the
Signal Corps BC-946, which was purchased under an USAAC contract.
The ARA schematic is attached.
The usual way to match the high impedance to low impedance earphones
is a transformer with a male phone plug that was intended to bridge
the gap between high and low impedance equipment deliveries. The
Signal Corps was faced with that problem in the last half of the
war, and produced several variations of the MC-385 (TO-01-1-90
attached.)
I'd be happy to send you one of these gratis if you wish. Just plug
it into your phone jack and plug in the headphone into the MC-385.
Easy-peasy.