Can you help me find the Highest Quality Switch?

I am trying to build a switching component that will allow me to connect two amplifiers (speaker level input from two separate systems) to a single pair of speakers - enabling A/B switching between the two systems.

I do realize there are "sonic consequences" with adding a switch like this so I would like to minimize the damage by using an extremely high quality switch which operates well at both high and low currents.

Do any of you know of such a switch?