Amplifier and Speaker A/B switcher

That one by AVA looks like the only device that will really protect your gear.  The Chinese company Douk makes exactly what you are looking for but not so sure I would trust my equipment into that thing.   

I've been using a switch made by Beresford of England. It allows me to switch between my mono block tube amps and my SS amp to the same set of speakers. Works fine and even has resistance added to protect your tube amp if left on when not switched in. I think Declare offers a similar switch.

J.Chip

I use an amplifier switch made by Dodocus in Germany (dodocus.de). It is super high quality. As of a couple years ago it cost $460. Well worth it.

I wonder if this one would suffice, good price: 

https://www.ebay.com/itm/402999423706

OP,

Switching the banana plugs is certainly a good way to assure no impact  on sound.

The higher resolution your system, the more prone you are to hear a switch box. Given your equipment, I think a high end audio switch box, would be indiscernible in your system and be more convenient.