The 14Q7 is an 8-pin lock-in base (Loktal) pentagrid converter tube designed for mixer and local oscillator service in superheterodyne radio receivers. It combines oscillator and mixer functions into a single glass envelope to convert incoming radio frequency signals into intermediate frequency signals. It operates with an indirectly heated cathode on a 12.6V / 14.0V heater supply. Sylvania, RCA, GE, and Philco manufactured the 14Q7 to RETMA specifications using T-9 glass envelopes. It is functionally identical to the 7Q7, differing only in its heater voltage rating.