Volume control for music and commentary ratio - has transistor control unit to maintain constant volume ratio

摘要

The volume control system is for audio recording and ensures that a constant volume ratio is maintained between music being recorded and an accompanying commentary. Input from either a microphone or direct source is applied to two inputs (2,3) of a preamplifier (1). Output is fed to an output amplifier (5) coupled to both a loudspeaker (3) and magnetic tape recording head (8). A transistor circuit (17,21) allows a required level to be set and an LED indicator monitors the level. When a microphone (26) is switched in (27) for commentary recording, a constant ratio with the music volume input is maintained.