Shorter Oxford gives 'gaff' as any public place of amusement … popular theatre, a music hall (mid C18 -- and also known as 'penny gaffs') so there may be a link with the entertainment industry -- perhaps the 'gaffer' (foreman) was in charge of the tape.

P L Fermor: Peasant girls, bewildered gaffers with tangled beards [punctuation is correct!]