David

When I connect the 2AOCPH-HR4 cable directly to the Red XLR - minijack cable, there is no noise. Adding the 302 reveals the noise. When I have the 302 & thez 2AOCPH-HR4, I have no noise either.

But ... you gave me the idea for the solution.

I unsoldered pin 1 on the Micron 2AOCPH-HR4 3 pin XLRs and the noise disappeared when plugged into the 302. Yippeee.

On the 2AOCPH-HR4, Micron solder a little bar that connects pin 1 to the XLR casing and I thought that it might be the casing / pin 1 connection that was bringing the noise, but sadly it was not that. So I have "floating" XLR cables. Not sure if that is a problem. I will have to check if the 2AOCPH-HR4 works in other configs.

I still have no idea why that single connection makes all the difference.
Thanks for all your help.