MOTM

I see from the tiny circuit boards, that it would be possible to
> add a second transformer to handle the "ring" signal and truly balance the
output.
> Perhaps that's a project for later...

I guess you won't need any extra transformers, just connect the "GND" side
to "ring" rather than sleeve and that's it. (A mono plug will automatically
connect ring and sleve then.)
I've never seen this box myself - I wonder why it would not be connected
like this from the start. I'll ask Stefan about it next time I meet him.

JH.