KVM for audio only?

C

coax

n00b
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Feb 25, 2004
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I just bought a KVM switch for my two comps but it has no provisions for audio. I want to make a switch box that I can use one set of speakers between two comps by turning a switch like a audio switch. Any body have a schematic or plans?
 
A simple 3 pole switch will do it, you may be able to use a double pole switch, but you'd have to hook all the grounds together, and I'm not sure that's a good idea.

You could also just get one of those video selector switches for TV, and gut it, and rewire it for just the audio. You might be able to pick one up for cheap.
 
Assuming that you're talking about switching the low level inputs.
audio_switch.jpg
 
$1.00 says that the schematic posted above won't work as desired.

The brutal fact is that "ground" on most computers is in fact the power supply ground. For those of us doing biomedical instrumentation, that makes for a lot of fun trying to get rid of 60Hz noise.... But I digress...

Anyhow, my suggestion would be to get yourself a DPDT (double pole, double throw) switch, connect one channel to each pole, (with the common being the signal destination) and connect all the grounds together, since they're more than likely at a similar potential anyway, especially if you have your two boxes plugged into the same outlet. If you're worried about differing ground potentials and you have powered speakers, (i.e. not headphones)tie each of the signal source grounds to the signal destination ground through a 1K resistor. This should limit any ground loop currents to minimal levels, unless the guy that wired your residence was completely incompetent...

Good luck, & don't blow anything up...
 
Originally posted by Aristarchus
$1.00 says that the schematic posted above won't work as desired.

The brutal fact is that "ground" on most computers is in fact the power supply ground. For those of us doing biomedical instrumentation, that makes for a lot of fun trying to get rid of 60Hz noise.... But I digress...

Anyhow, my suggestion would be to get yourself a DPDT (double pole, double throw) switch, connect one channel to each pole, (with the common being the signal destination) and connect all the grounds together, since they're more than likely at a similar potential anyway, especially if you have your two boxes plugged into the same outlet. If you're worried about differing ground potentials and you have powered speakers, (i.e. not headphones)tie each of the signal source grounds to the signal destination ground through a 1K resistor. This should limit any ground loop currents to minimal levels, unless the guy that wired your residence was completely incompetent...

Good luck, & don't blow anything up...
Click to expand...

Argh, at first I didn't believe you...so I took a PS, and checked the resistance from power supply ground, to internal ground. 2 ohms. DAMN!

To the thread starter: Don't use my circuit. Do as the above poster recommended, and get at DPDT switch, and switch the signals, tie together the grounds.
 
Heya coax,

ive HAD an kvm before I discovered that nice remote desktop utility of win200x. And for sound, buy a cheap/small no leds audio mixer. Ive got myself a little 28 ch studio mixer (music hobby) but its the same idea. It solves the problem when switching from comps and playing winamp on computer B, and playing Zool on computer A :D
 
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