Multiple input audio selector

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First off, Im not gonna lie, Im a total newb to real electronics work. Sure, I can solder and use a multimeter, and Ive done my number of electronic fixes and mods over the years, but Ive never had to make one from scratch before, and dont know the fundamental design behind them. Well, Im ready to learn now.

That being out of the way, here's what I am TRYING to build.

I want to build an audio selector. One that will allow me to hook up 5 audio sources (via 1/8 stereo plugs) without 1 output.

The trick is, I want to be able to activate several of the switches at once. So, for example, I could listen to source #3 while monitoring source #1. The output will be going to standard amplified speakers (like tons available for computers).

I hope that explains what I need. I'm here to learn and the share, and I didnt find anything when I searched the forums. Anyone care to give me a nudge in the right direction?

Thanks :)
 
Thats cool, and I appreciate it. But since Im a beginner, Im trying to understand why something like this wouldnt work:

http://www.jamsoft.biz/ttt/diag1.jpg

The editor I was using wouldnt break the lines, so please just assume where lines cross, they arent connected. And assume also that this is mono for now (2 connector, + and -). I tie all the - together common, and switch the +.

Ive got an electronics learning kit Im using here, but it doesnt cover audio sources.

Also, can anyone suggest a better circuit drawing program than SmartDraw?
 
Ive been scouring the internet for hours and still cant find anything like my idea. Can anyone tell me if its just bad design?

Also, how many posts do you need before you are no longer moderated? The message says a "few", but I was just wondering :)

*Edit* - 6 seems to be the magic number :)
 
Hello Codewizard,

Your idea will work if you use it as a single router.
i.e. one input gets mapped to one output.

If you have multiple inputs and multiple outputs you start running into loading issues, where the second output loads the input to the 1st output, and loads the output of the first input (and all conbinations thereof).

A simple way to remedy this is to use a buffer or unity gain amplifier in the chain somewhere. Place the buffers on the outputs side of the switches.

Professional mixing desks use a similar idea however they usually dedicate a single channel (often stereo) to the monitor mix and each input channel has a buffer and a switch to connect it to the monitor bus.

Feel free to contact me to discuss further,

Jared
apollyon25@hotmail.com
 
and as rfbrw correctly points out, the SSM2402 / SSM2412 is a device designed to do exactly what you are wanting. Avoiding the pitfalls I mentioned.

So it wouldnt surprise me if there is that very same part in some of the professional mixing desks I have seen.

I am not sure if Analog Devices have a new version of this available, they may even have multiple channel versions.
Go to www.analogdevices.com and have a look.

Jared
 
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