New to me 6300 audio setup

You cannot count on the inside of the Inrad Mics being wired correctly for any configuration. I bought an Inrad M629 a few years back from DXE. The cost of the mic was attractive and I desired to get an XLR mic connected through the back panel of my new to me 6500.... After wiring an OCWhite mic boom that required the XLR for the rear of the radio a mic cord to the base of the boom which is 15" tall and an XLR connector, the mating connector to the swiveling boom with its cord threaded through it to another XLR that connects to the mic. Whenever I touched the mic case itself while transmitting the radio sent out quite the HUM... I suffered through a whole phone contest. Several months later I finally said I must have gotten the ground and one of the balanced lines swapped around. I pulled each connector apart one by one; all were built to industry standard wiring connections. all the way to I better open up this mic and figure it out why it's humming... I should have questioned it as the mic itself had come with a small plug connector and cord to an xlr to plug in the back. When I opened it up I believe it was 2 and 3 were swapped IN the mic on the rear connector. as these mics are not single ended like a D104, but should be wired as balanced audio, You're sort of on your own as the 6300 has only a single ended input You can try to connect the minus and ground together and feed them to your radio. But with the balanced input I never tried to actually use the mic as a single ended mic. That should require a shielded mic cord. But suspect the mic wiring and your attempt to hook it up single ended... Erika DD