> Is there an electrical engineering reason you have the XLR shell &
> shield connected?
Yes, but it is theory, not practice. Theoretically, the conductors in
side the XLR are not shielded, but in practice with a balanced line
this is not a problem. The cable screening is of course insulated,
which prevents ground loops, but the XLR shell is not. My mistake.
There is a theoretical solution which is to connect the shell through
a 100 ohm resistor which reduces any ground loop current, but the
practical solution of leaving the shell floating is the best.
When I made an unbalanced-to-floating transformer box for my Brinibox
rig, I grounded everything to the left cable shield only. I always get
a classic ground loop if I double ground any mics at the far end. I've
measured volts between earth and ground, so there must be quite a
current flowing through the landscape around here.
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce