All you need is one DPDT switch to control one lead to each speaker.
The other leads can be common to the two speakers as shown below:
View attachment 121423

All you need is one DPDT switch to control one lead to each speaker.
The other leads can be common to the two speakers as shown below:
View attachment 121423

Apologies for opening an old post (I couldn’t find a way to direct message).

any issues using this setup for switching:
-one Turntable –> into two phono preamplifiers —> into one integrated amp? This is not clear in my head as to the best way to accomplish. Thanks!
wes

Mod: link to old thread.
https://forum.allaboutcircuits.com/threads/audio-a-b-a-b-switch-help.132703/post-1103697

 

one Turntable –> into two phono preamplifiers —> into one integrated amp?

Not clear what you want to switch(?).
Why two preamps?
Typically you can parallel the output from the turntable into the two preamps without a switch.

To minimize noise pickup, low-level audio switching is done with RCA connector switches.

 

This is indeed a puzzle: One turntable, two pre-amplifiers?? That could be a large diameter TT with more than one arm and one cartridge, as used for some DJ setups where there needs to be a backup.
So the immediate questions are about the details: Is this a stereo setup?? Are those stereo or mono pre-amps??
In ALL of the "integrated amplifiers" that I have seen, the integrated part means that the phono cartridge input to the pre-amplifier is a part of the "integrated amplifier".
My SONY TAE8450 includes two phono inputs and a 4 position switch. But I don't have the manual so I can't share the circuit. But if you can find the circuit on line, that will be one scheme that works.
Rather than dig back to an old post, I am asking questions that may have been answered already.
Switching the very low level signals is not quite trivial.