Clue: Homeless tramp is fed by street musicians (7)
Answer: OBOISTS
Explanation: Definition: musicians

(h)**OBO** ("tramp" with no H (home)) + IS [fed by] St. (street)
 
*Not sure of the parsing for this. H for "home" doesn't appear in any of my dictionaries, so wonder if "homeless" is being used as a way of taking away the first letter, but I don't think that's valid either?