right, that's the Bela stereo headphone out, that's entirely a different signal from the one that goes to the Audio Expander capelet, whereas the one I recommend is the same signal that goes to the audio expander, but earlier in the signal chain. You can try to get the signal from the 10x1 analog out header on the audio expander capelet, but as that has a 2.5V DC offset, plugging headphone into it will most likely distort it beyond recognition. You can try to apply a large capacitor in series between that output and the headphones and hope to get something out of it, or you can follow my recommendations above.