I am sure that the fix is as I describe specifically for compatibility between the WiiM and Aiyima/Douk and similar current Chinese mini amps. The mini amps require a stereo plug. Certainly the signal out of the WiiM is not stereo, it probably has to do with the contacts within the socket of the amps.
This is separate from the issue discussed on this thread before post 34.
Aaa, yes, I forgot about "post 34"..
Then you get the Parasound components that used the 2.5mm sockets... and before that two screw terminals.
I bought a bunch of plugs and I got lots of wire, solder and a couple of soldering irons. I use only mono plugs.
No Chinese amps.
Back to post 34.