Say you had an amp with 3 channels, and you wanted to be able to switch between them, with 3 buttons (one for each channel, of course), what kind of crazy logic gate system would you have to use? opto-isolators are to be used to actualy switch the channels, and for it to be 'pop-less'.
I've been thinking about this for ages, and my advanced circuit simulation software (ok, crocodile clips
Thanks, to anyone ho can help me.

