Switching on the speakers is risky. I have actually just paralleled
the outputs of radios and stereos at the speaker with no problem as
long as everything was DC blocked and the voltages present never
exceed what the PA stages could handle.

I also did this by building a mixer stereo preamp that would take
input from earphone jacks from an HT and portable scanner into the
car stereo after its own volume control. The source radios had their
own volume control and the stereo had its volume control. All this
so I could run in a pickup truck. I had no muting, but this could be
done with COR switching of mute gates.

An aftermarket add on may be more viable with stereos that have
preamp outputs to various amps, but COR usually needs to be brought
out of the radio.

I do remember seeing such a thing but not lately. It was activated
by RF sensing so only muted when transmitting.



"Jerry" wrote in message
...

"FrankW" wrote in message
...
Anyone every heard of a device that would override
the speaker of a stock stereo from a CB?
Something that would cut out the sound from the
stock car radio and put the CB sound into the stock speaker
Thanks in advance

How about a relay?

J