Hi, I posted this on the cable forum but the thread got buried with no replies... hoping I'll have better luck here.
The cable for my AKG K240 Studio headphones crapped out, so I bought a female mini XLR plug to build a new one. I used this document from AKG support as a guide - if you look at page 5 there are schematics for the cables.
The issue I'm having is, instead of getting stereo audio, now I'm getting a mono sum of both channels with one of them inverted (so anything that is at the same level on both channels cancels out). To test this, I plugged them into my receiver and played with the balance knob. Even with the balance knob turned all the way to R or L, the sound is going to both capsules. When it's dead center, there is some phase cancellation.
I've tested all my connections with a continuity tester and they are all correct and nothing is shorting, so what could be causing this?