Go Down

Topic: Audio switching (Read 2 times) previous topic - next topic


Check the CD4066 I remember it was an excellent analog switch having several channles. Maybe its useful or give you some ideas.
Perseverance is 90% of the solution. The remaining 10% is more perseverance.


Using relays often introduces a noticable "pop" into the audio stream. You might googgle for audio multiplex to see what products are already available. The analog multiplexing chips would be worth looking into.
Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   8)


I agree, the CD4066 will prevent that "popping noise". I remember it was a very very simple and reliable device.
Perseverance is 90% of the solution. The remaining 10% is more perseverance.


As they say, engineering is a game of compromise.  Pick your poison.

Yes, with relays, there could be ticks/pops depending on how large the waveform you're switching (and at what point in the waveform you're doing the switching.)  The same could also happen in switched gain controls.  -- for switches, one can use a make-before-break switches  -- but these are usually special order items and a bit more expensive than the normal break-before-make switches.

The other option is adding a zero-crossing detector (which is what chips like the PGAxxxx series do), they only switch when the waveform is a few millivolts above/below the zero level. It's not perfect, but minimizes zipper/tick/pop noise.

Of course, one can look for analog multiplexers with built-in ZCD... but then again you compromise on the high Ron resistances, variability/tolerances  between parts, and the low analog headroom (13dBu theoretical max., ideal case for +/-5V supply)


The way you have it in your schematic isn't the same as how you have it wired up!

Go Up