My old radio has some sockets at the back labelled P.U. What are these for?
A. The letters ‘P.U.’ are short for ‘Pick-Up’, which was another term for a transducer, usually magnetic, with a pivoted arm that allowed it to track records with a replaceable needle, converting the physical oscillations of the 78 rpm record groove into electrical impulses. In other words, a record player. The sockets allowed gramophone records to be reproduced electrically. It was possible to buy magnetic heads to fit in place of the original acoustic diaphragm used on wind-up gramophones, also complete arms. Some enterprising makers produced ‘add-on’ units said to convert radio sets into radio-gramophones – at a fraction of the cost of same. These consisted of an electric-powered turntable and pick-up, housed in a cabinet of some form. The needles were the standard type – steel – but I understand that it became possible to fit sapphire-tipped ones which would of course have lasted much longer. An alternative name for such sockets is ‘gram’. These old magnetic pick-ups should not be
