Swell to maximum volume (4)

I believe the answer is:

toff

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'swell' is the definition.
(wealthy or high-class person)

'to maximum volume' is the wordplay.
'maximum volume' becomes 'ff' (I am not sure about this - if you are sure you should believe this answer much more).
'to'+'ff'='TOFF'

Can you help me to learn more?

(Other definitions for toff that I've seen before include "Posh geezer" , "An informal aristocrat" , "Dandy" , "Person of the upper classes" , "Aristo" .)

I've seen this clue in The Guardian.

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