Amplifier and Speaker A/B switcher

I use this.. it works for me and if I’m A/B some speakers or an amplifier it does the job. Would I leave it in line forever? Nope but I can use it to hear what I need to hear.

SOLUPEAK P3 2-Way AMP Amplifier... http://SOLUPEAK P3 2-Way AMP Amplifier... https://www.amazon.com/dp/B0BGHMGY7J?ref=ppx_pop_mob_ap_share

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