Miserable -- as might be trombonist? (7,3)
I believe the answer is:
brassed off
'trombonist?' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'miserable as' is the wordplay.
I cannot really see how this works, but
'as' is present in the answer.
This explanation may well be incorrect...
'might be' acts as a link.
Can you help me to learn more?
(Other definitions for brassed off that I've seen before include "Exasperated" , "Fed up" .)