I have a brand new Marshall DSL20 amp. It works fine without headphones but I get nothing out of my headphones when I plug them into the audio in/emulated out ports. while doing tinychat with friends. The headphones definitely work, and when I plug them in the amp makes a small popping sound but audio keeps just coming out the general amp instead. I just tried both because the other one didn’t work, And no, the headphone and mic jack are separate.