Several things happened in one evening:
I overloaded the electricity in my room leading to all the plugs being switched off. Headphones were working at this point.
I then tried to hook my Macbook Pro (Early 2015) into a small amp (Orange Microcrush) to get some sound. I only got static and noise.
When I tried to listen to music on my headphones, I could only hear static and mechanical noise. A red light momentarily appears in the headphone port when I remove the headphones.
Interestingly, the speakers still work.
I've tried resetting pram and resetting core audio - all to no avail. Right now I have very faint audio coming out the right ear of my headphones. This, however, is unstable.
I appreciate any help you can offer.