Switch for cockpit speakers

[MILLPOND]

I want to install some small cockpit speakers. I already have two in the cabin. The radio is a normal car stereo which has an option to fit four speakers in total.

I want to be able to turn the cockpit speakers off to avoid causing a nuisance, but don't want the hassle of having to use the fader control. I therefore want to fit a switch under the coaming of the cockpit to control the two speakers. It will be quite well sheltered from the elements, so doesn't necessarily need to be totally waterproof.

Do I need a DPDT switch or DPST switch? And I don't know much about electronics, so is it a simple job of putting the two positive wires and the two negative wires to the speakers through the back of the switch, or is something more complicated needed?

Any ideas where to buy a switch like this?

Thanks

 

[boatmike]

Maplins

 

[KevB]

In my youth car stereo speakers shared the common, even between front and back. Often just down to earth. So if things are still the same just a single pole toggle will do on the common to that pair.

 

[Tintin]

In my youth car stereo speakers shared the common, even between front and back. Often just down to earth. So if things are still the same just a single pole toggle will do on the common to that pair.

+1

 

[nigelmercier]

In my youth car stereo speakers shared the common, even between front and back...

You must be very old then

With any set bought in the last 20 years, there will be 4 wires to switch, unless you want to just disconnect them, in which case there are only 2. The latter will need a DPST, look at CPC.

Personally, I prefer separate volume controls front and rear, which is what I'm making for my amplifier. Just need to get a round tuit.

 

[rogerthebodger]

I have separate speakers in my Saloon, Wheel house, rear cabin and cockpit each switched with a 4 pole double throw toggle switches.

Like this from your local electrical shop like maplin

http://www.jameco.com/1/1/51753-mta406p-toggle-switch-four-pole-double-throw-configuration.html

 

[Tintin]

You must be very old then

With any set bought in the last 20 years, there will be 4 wires to switch, unless you want to just disconnect them, in which case there are only 2. The latter will need a DPST, look at CPC.

Personally, I prefer separate volume controls front and rear, which is what I'm making for my amplifier. Just need to get a round tuit.

There will be 4 wires, but if you put a multimeter across the -ves on continuity / ohms you will probably find they are connected - they certainly are on my 2 yr old sony, so ..

a) at the speaker end common both -ves together and run one wire to your single pole switch,

b) then run one wire back to the radio commoning both -ves if you wish at the radio, but not really necessary.

simple

 

[nigelmercier]

There will be 4 wires, but if you put a multimeter across the -ves on continuity / ohms you will probably find they are connected ...

Very unlikely. Most amplifier outputs, especially those that run on 12V, are differential. You may appear to have continuity, but it is due to the low Z of the amplifier, or your meter switching on various diode paths.

Update: My Sony radio has a TDA8588 output amplifier. The datasheet says: "The TDA8588 has a complementary quad audio power amplifier that uses BCDMOS technology. It contains four amplifiers configured in Bridge Tied Load (BTL) to drive speakers for front and rear left and right channels... Both front and both rear channel amplifiers can be configured independently in line driver mode with a gain of 20 dB ... differential output."

As this image shows, the outputs are all independent of the chassis or ground: