[Boatanchors] Collins 75S-3C audio output transformer

[Darrell Brooks]

Peter Dahl says 2500 Ohm primary. 4/500 ohm secondary. 1.9 watts

On 4/26/2026 11:59 AM, n2lxm--- via Boatanchors wrote:

> While setting up my new operation position, I found that I had no
> audio from the receiver. I pulled it to the bench and found that the
> audio transformer has an open primary. Trying to find and information on
> the transformer(primary impedance) has come up short. Tried NSN
> 667-0302-000, found plenty of E-bay hits, but no spec's. Dose anyone know
> what the primary impedance is. The tube data for the 6BF5 shows class 1A
> as 12 K, which seems a bit high. I pigged tailed an old AA5 output
> transformer in and it works. And help would be greatly appreciated.