Recording Control

009 RECORDING CONTROL AUDIO & HI-FI The circuit presented here is intended as a recording level control for cassette recorders. It enables the reading on the vu meters to be kept out of the red sector without the necessity of the recorder"s level control to be adjusted. This is particularly useful when speech is recorded. The recording signal is controlled via two voltage dividers, each containing a light-dependent resistor - LDR. Unfortunately, these devices introduce slight distortion, but that is still better than a lot of distortion through overload- ing of the tape. The circuit monitors the signal level at the headphone output of the recorder. The signal there is rectified (half wave) and then applied to Tl. The speed with which T1 can react is determined by Cl. As shown, the attack time is set at 3 ms. The release time of the circuit is determined by R4-C4 and is much longer than the attack time: about 100 ms. The voltage across C2 determines to what extent the signal to b...