Ted Shea ruined the listening device (7)
I believe the answer is:
headset
'listening device' is the definition.
(I've seen this before)
'ted shea ruined' is the wordplay.
'ruined' indicates an anagram.
'ted'+'shea'='tedshea'
'tedshea' with letters rearranged gives 'HEADSET'.
'the' is the link.
(Other definitions for headset that I've seen before include "communication aid" , "Radio operator's equipt." , "Earphones and microphone assembly" , "One covers the ears" , "Cans" .)