[Patrick]

So using the schematic, and feeding in a stereo source, only one channel will be heard? That means you could only feed in a monaural source?
If I wanted to combine both channels, is their a way to do that and still eliminate a switch?

[Ron Ramirez]

Patrick

Please don't let yourself be confused. The circuit I posted allows you to feed both channels of a stereo source and have a mono output (both channels combined). Notice a 0.1 uF capacitor on the jack, which serves to tie left and right channels together. The 0.1 uF may not result in ultra high fidelity sound, but you aren't going to get that out of the typical AM radio anyhow.

In addition, the closed circuit jack does the switching for you with no need for a separate switch.

If Peter Balazsy says it works, that's good enough for me. I confess that I have not used this myself, but I will if I ever have occasion to perform such a mod in the future. I now regret that I didn't remember this when I added an external input to my RCA C15-3. Having no switch might have been nice.

[Patrick]

Thanks Ron. I kinda figured that was the purpose of the cap, but I wasn't sure. I just started recapping the radio, so it will be a few days until I'm ready to install the jack and see if it works. I'll post the results. Thanks again.

[Ron Ramirez]

Good.

Pay careful attention to the connections of the jack if you are using the closed circuit jack. The mod will not work if you miswire the jack.