When we need to switch inputs on an analog preamplifier we use a switch. The kind of switch we use affects sound quality.
For years we had only mechanical switches from which to choose. Standard switch contacts in those days were nickel or tin-plated while the more expensive and better-sounding styles were either silver or gold.
These worked great and sounded excellent, but they had a problem. They were nearly impossible to remote control.
The customer's desire to control their systems from their easy chairs drove us designers to replace mechanical switches with electromechanical relays. Relays were available with the same contact materials though because they weren't self wiping (like mechanical rotary switches), their slap and connect operations produced a slight degradation in sound quality.
Relays are expensive and cumbersome.
Along came silicon switching. Low cost, quiet, reliable, and without the problems of contact degradation. Sonically, they fell into third place, but not too far behind relays.
Engineering is always a matter of compromise. We give up one thing and in exchange get something else.
In most of PS Audio's PerfectWave series of analog audio products, we rely upon a combination of electromechanical and electronic switching.
Common sense, practical, excellent performance.