Philips EL 3503
The BBC Radiophonic Workshop had three Philips EL 3503 tape recorders which ran at 7½ and 15 i.p.s.
there were three Phillips tape recorders [which] did not run at the same speed.
They seem to have arrived in late 1962 or early 1963, as a note to Delia's third Workshop piece, Arabic Science and Industry reads "First Hi Fi sig as Workshop had just got new tape machine (Phillips)".
- Philips EL-3503, Radiophonic Workshop, a gallery of photographs of the deck, by someone who by chance bought one of the very machines used at the BBC.