2channel audio mixer or switch with automatic src selection

[lexus]

Hi,

I want to build an 2 stereo channels switch with automatic selection of an primary source. So, if on ch1 is a signal it is routed, if not, channel 2 is routed to output.

Can someone give me a link or some basic idea how to do this....

Maybe a good quality mixer is possible, too (If it is not to expensive).

Bye Dan

 

[mozikluv]

audio mixer

hi,

the audio mixer you can make, there are lots of mixer circuits in the net like at the http://www.discovercircuits.com

as to your auto selector, i dont get your conceive idea. you said if there is a signal in chan. 1 it is routed to the amp, if none, chan. 2 is routed.

what you really mean is, any signal that is inttroduced to the mixer regardless of which channel it appears will be sense by a circuit and rout it to the amp. that's a neat idea. am interested with whatever replies or ideas will be given :wink:

what is needed here is a random signal sensor that samples all inputs with the presence of a signal. however there could be a problem like what would happen in case a another signal is introduce while there is an ongoing signal coming in :shock:

 

[Nigel Goodwin]

I think we really need more information, such as exactly what you are trying to do? - and why?.

If you want a switched source, it's not a mixer - and if you want a mixer, it's not a switched source.

Tell us exactly what you want to do, and we can probably make suggestions.

As for actually detecting audio, that's simple enough - just use a full-wave rectifier, just as you would for a VU meter. The tricky part is getting the timing correct, it needs to work like a PPM meter - with a quick attack and a slow decay - otherwise it would switch channels in between words - which, presumably, wouldn't be wanted. Adjustment of the timings would probably be a matter for experiment - you could probably use VOX (voice operated switching) for amateur radio transmitters as a starting point - they face the same critical timing considerations, and usually provide an adjustable delay control.