Perhaps in step with old instrument (6)
I believe the answer is:
spinet
'old instrument' is the definition.
(I've seen this before)
'perhaps in step' is the wordplay.
'perhaps' indicates anagramming the letters.
'in'+'step'='instep'
'instep' is an anagram of 'SPINET'.
'with' acts as a link.
(Other definitions for spinet that I've seen before include "Small 12" , "organ" , "Type of early harpsichord" , "Early keyboard instrument" , "Old keyboard instrument" .)