Is there a way to switch between the outputs of 2 separate low power audio sources to 1 speaker without damaging the amp, or causing electrical noise (pop, snap, crack).

 

Yes, but it requires a bit more smarts than a simple switching circuit. The process is used in high end audio equipment with multiple input sources.

1. Smoothly ramp the audio output down to zero.
2. Switch to the alternate input source.
3. Smoothly ramp the audio output back to the previous setting.

Of course, this requires that your audio output be controlled by a DAC. If you don't have one maybe it is time to upgrade.

 

When you say 1 speaker, do you mean one amplifier driving a speaker, and the two audio sources are line level inputs to the amp?

If so, then do the two audio sources share a common ground?

If so, then a better-than-average analog mux chip can do the switching. Linear Technology (LT) (now a part of Analog Devices (ADI)) has a line of "clickless" audio switch parts. They do what Papa described, all inside one chip. Maxim also might have some, but I'd prefer LT or ADI.

ak