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Re: Complete the DC circuit?Yes, you're correct, the XLR shell is supposed to be isolated from the pin-1 shield connection. However, I've seen a lot of import XLR cables that have the shell bonded to pin-1 from the factory, which as you mention is against AES standards. Note that pin-1 connected to the shell can short across the metal body of a DI box that has a metal body XLR jack. That takes the ground-lift switch out of the circuit so it can't open up the XLR to Phone shield path as intended. So the next time you can't get rid of ground loop hum by flipping the ground/lift switch on your DI box, open up the XLR female cable connector and see if the shield is also bonded to the XLR shell tab. If so, cut it loose and you'll be lifting ground loops properly.
Re: Complete the DC circuit?
Yes, you're correct, the XLR shell is supposed to be isolated from the pin-1 shield connection. However, I've seen a lot of import XLR cables that have the shell bonded to pin-1 from the factory, which as you mention is against AES standards. Note that pin-1 connected to the shell can short across the metal body of a DI box that has a metal body XLR jack. That takes the ground-lift switch out of the circuit so it can't open up the XLR to Phone shield path as intended. So the next time you can't get rid of ground loop hum by flipping the ground/lift switch on your DI box, open up the XLR female cable connector and see if the shield is also bonded to the XLR shell tab. If so, cut it loose and you'll be lifting ground loops properly.
