Solo schematics for DIY mixer

Hi all;

After sailing few months on the web cannot found any schematics for build the solo system -solo buss- for my mixing board that I build now.

I read hundred articles about how works the solo button, the solo-in-place but
no schematics about this.

Can you give me a helping hand for looking the schem or link?

Thanks in advance.

Merry Xmas and better New Year.