Building Your Own KVM Switch...With Audio Connectors?

Michael B asks: "I recently bought an 8 port KVM to switch between various workstations and servers at home, and I'm realizing what I can't switch is audio! I've seen 4 port audio/video type switches (for things like switching between video console systems) but this doesn't address more than 4 ports and having the adding RCA/S-Video is a waste. I've thought of building one from scratch using Radio Shack parts, but can't find any info, such as a schematic, online. Does anyone have any ideas or sources of info for this one? Belkin seems to make a 4 port KVM with audio, which would be nice, but I need more than 4 ports. Thanks for any help!" After a bit of digging, I found this monster, which does 8-port KVM and audio, but that weighs in at a hefty $500USD, which is rather expensive. Has anyone managed to find schematics to such switchers so that folks, who aren't afraid of soldering irons, can build their own?

Comments

cheaper solution

[rumpledstiltskin]

instead of spending $500 or spending all your time building your own switch, just buy a tuner with multiple inputs. you get to have your switch (at the cost of having to push one more button, although if you use the remote it shouldn't be all that strenuous) and you could hook up some advanced (dolby, dts, whatever) audio to it if you'd like.

Re:cheaper solution

[TimeTrip]

It also allows you to separate the audio from the video/keyboard/mouse. Often times at work, i switch between machines on my KVM switch, but keep my headphones connected to just one machine because its playing my mp3's :). If the audio was run throught the KVM switch i would probably go insane.

Mix instead?

[Piquan]

How about just building an audio mixer? IIRC, Forrest Mims's "Engineers Notebook" (the one on op-amps, I think) has a multi-channel mixer that allows for an arbitrary number of inputs. This way, your MP3s don't stop when you go to work on your laptop, etc.

Here's an idea

[HotNeedleOfInquiry]

If your 8-port switch has led select lights for the port that is active, bring out a wire from each of the signals that drives the leds and wire each of them to a simple buffer transistor and relay.

Each of the relays would gate the respective sound signals onto a common bus. Use a double pole relay for stereo. 2N2222 (npn) and 2N2907 (pnp) are available from Fairchild through Digikey in TO-92 packages and would be a good choice for a relay driver.

Likewise, an Omron TX2-5V is a reasonably priced DPDT telecom relay with a 5v coil, also available from Digikey.

Re:Any recomendations for mixers?

[John Meacham]

the Samson PL1602 is a real nice cheap rack-mount mixer. I use it to mix all my audio inputs, plus it has its own headphone port of the mix, and I can send arbitrary channels back to the computer (independent of what i am listening to) for recording audio from other devices.

Re:the easy way

[Mononoke]

your spelling is even more creative than the idiotic viola.

You think that's bad, you should hear some of the grammar used by the cellos.

Do it in software

[Anonymous Coward]

How about that:

Machine you work on:
cat /dev/audio | nc 192.168.100.1 48050

Machine you plug your speakers in:
nc -l -p 48050 > /dev/audio