5 PCs sound to 1 speaker with common GND

[Old Grey]

I have 5 PCs that I want to switch between, to 1 set of speakers.

It comes down to a 3P4T rotary switch, where 1 PC misses out, or common all the GNDs and run a 2P5T rotary switch.

Basically I want to know if common-ing the GNDs will produce distortion or something bad.

Also curious to know if a constantly connected splitter between 2 PCs and 1 speaker, apart form the sounds being on top of each other, can damage one PC if both are outputting because they are connected directly together.

Thanks

 

[Audioguru]

If the amplifiers are "bridged" then each of the two wires for a speaker is driven by its own amplifier and if you "common them together" then you are shorting the amplifiers. A shorted amplifier usually becomes destroyed.

If you connect the outputs of two or more amplifiers together then they do not mix the sounds together, instead the outputs of the amplifiers "fight" each other and probably will be destroyed. One amplifier output will try to go positive and the other amplifier output will try to go negative and with nothing to limit the current there will be distortion and smoke.

 

[Old Grey]

I don't know what's on a sound card in a PC, but it looks like keep them separate to be safe. 4 PCs and a 3P4T rotary it is.

Is there any circuit I can make to light a LED as in indicator, based in rotary switch selection?

Thanks

 

[Old Grey]

I found these 5 pin 3.5mm stereo audio sockets, any ideas on how I can use the internal switches to light a LED.
Is it as simple as using them as a switch and passing 5V through them, or is using a mains power supply risking a ground through the PC because it's not isolated any more.

 

[Audioguru]

You show a stereo jack that disconnects two unbalanced (not bridged) stereo loads and connects the two new stereo loads that are plugged in. There is no third pole to switch on an LED.

 

[Old Grey]

Looks like you need a double ganged rotary switch.

I think I will just go for a bigger knob.

Thanks.