Amplifier and Speaker A/B switcher

"swapping the speaker cables by hand" That's the way most of us do it.

What about turning the amps around so the speaker connection are facing outward?

How often do will you be doing this?

If I had to do it again, I.would still go with a box, a bunch of dual banana jacks and a pair of dual banana jumper cables.  I don't think there is a switch that is as neutral transparent as a banana plug or screw down connection.  High current solid state switch?  Works for line level switching.  I'll throw this one at McGowen.

I used to demo 3 amps: Fisher 30 wpc Tube Mono Blocks 80az; Fisher 35 wpc 500C stereo tube receiver; McIntosh 250 wpc SS MC 2250 stereo amp.

Start with some hooks behind each speaker at 'reachable height'

Cable from each speaker with female banana long enough to hang on a hook behind each speaker.

3 sets of speaker wires (1 set/amp). I wrapped each set of speaker wires with different color electrical tape at each end to know which amp.

With male banana plugs that have tightening pins (also hanging from 'reachable hooks'. They insert loose, then tighten the pin. Tightening because frequent in/out not good for regular banana plugs

https://www.parts-express.com/Stacking-Banana-Plug-with-Dual-Set-Screws-Poly-Carbonate-Sh-091-3608?quantity=1

Lastly, you need to make A,B,C pencil marks on your volume control so they are 'matched' volume when comparing.

Same thing comparing cartridges, pencil marks to match volume.

I had a pair of such speaker switches, hand made with high quality connectors if you want to buy it from me. I have solved my problem now. One main disadvantage is that you need 6 high quality terminals on each - that is 12 high quality terninals plus quality connections and switch plus high quality labour. You need a budget to get what you want

to compare speakers from one amp, or switch which speakers are playing: I used an older version of this Niles unit, individual volume control for each set of speakers

https://www.crutchfield.com/p_190SSVC4/Niles-SSVC-4.html

smaller 2 speaker set unit

https://www.crutchfield.com/p_190SSVC2/Niles-SSVC-2.html

a little pricey but it Van Alstine

ABX Switch Comparator – Audio by Van Alstine (avahifi.com)