Author of Yellow Spring (6)
I believe the answer is:
orwell
'author' is the definition.
(I've seen this before)
'yellow spring' is the wordplay.
'yellow' becomes 'or' (heraldic term).
'spring' becomes 'well' (I've seen this before).
'or'+'well'='ORWELL'
'of' acts as a link.
(Other definitions for orwell that I've seen before include "Blair, Eric, d. 1950" , "The Road to Wigan Pier author" , "who wrote novels?" , "George -, nineteen eighty four author" , "Socialist author" .)