Running multiple radios through a single set of speakers

[kandkharris]

Our CD player/FM radio is set up to play through speakers located in the cockpit. I would like to wire up the audio output of the the SSB and VHF radios so that I would have the option of listening to them in the cockpit through those same speakers. I suspect that there is more involved than just splicing all the speaker wires togeather. Any guidance would be appreciated.

Kyle Harris
s/v Stap Isi
Madang, Papua New Guinea

[sailingdog]

Generally not recommended, as the speaker output of one can damage the speaker output circuitry of the other two devices.

If you really did want to do this, you could do it. Get an amplifier that can take multiple inputs and direct them to a single set of speakers. That way, if the SSB or VHF went off, it would cut the music, so you could hear the SSB or VHF message better.

Or make a small an audio mixer... see this site here: LINK

[Valiente]

I don't think he wants the SSB to cut in to the music program, but simply wants to switch inputs manually when he hears something of interest in the background. That's a simple A/B switch, but the impedence of the SSB external speaker needs to match that of the speakers.

It's been a long time since I turned a '50s console stereo into a '70s cheapo guitar amp, but that seemed to be the general idea then.

[sailingdog]

If that is indeed the case, an ABC switch would work quite well. However, I see that as somewhat less useful, since you would then have to pick one, and might miss out on the other two sources...

Also, given that you're supposed to be legally required to monitor VHF CH 16, if you have VHF on-board, the ABC switch idea is not all that useful. Having the VHF and SSB hooked in simultaneously would allow you to do that.

[duffer1960]

Audio is basically AC, therefore the diodes will sometimes conduct, and sometimes not. You would end up with one bad result, and one VERY bad result. The bad result is the diode would act as a rectifier and clip/distort the hell out of any audio. The very bad result is that one piece of equipment will still damage another. A switch is the only way. If you want to be able to monitor other things, the best solution would be to add seperate speakers for each device.

[camaraderie]

It is DEFINITELY going to destroy something if the output of one radio can be "seen" by another radio. You either need a 3way switch which will isolate each radio and pair it with the single speaker pair output OR you need a second set of small speakers...one which would run to your VHV and the other to your SSB since these are both MONO sources.

[sailingdog]

Ideally, you could make two small two-channel mixers and use one to combine the left stereo channel and the VHF, and the other to combine the right stereo channel and the SSB. That way, you could actively monitor both the SSB and VHF, while still being able to listen to your music. This would also allow you to know whether the call was on VHF or SSB, by which speaker it came out of.

[camaraderie]

Mixers go before the amp...not after.

[Idiens]

Most modern car radios have a mute connection, so that other services can mute the radio and take over the speakers. Maybe that facility could be used.

[sailingdog]

Does your stereo have a CD or AUX input?? If so, you could always run the VHF and SSB into the CD inputs and then select CD on the stereo to hear them, with VHF on the left audio channel and SSB on the right channel.

One reason I like having it go through the same amp as the stereo, is that if you have a cockpit mounted remote, you can effectively control the volume of the SSB, VHF or radio from the cockpit, without having to go below.