Recording/Playback Amplifier

EE 44 October 1987 RECORDING/PLAYBACK AMPLIFIER This amplifier enables accompanying slide presentations with stereo commentary or music whilst using a separate track on the cassette recorder for controlling the slide changer. This simple to build amplifier makes use of a 4-track re- cording/playback head fitted in lieu of the 2-track head in an ordinary cassette recorder used for audio-visual presen- tations. Four-track heads can be picked up occasionally from surplus outlets, or purchased as a servicing part for auto-reverse cassette players. The proposed signal assignment on the 4-track head is shown in Fig. 1. The non-used track in between those assigned to the stereo programme and the control signal ensures acceptable levels of crosstalk. The pro- gramme and the slide control signal can be recorded separ- ately. If required, the control pulses can be erased by revers- ing the cassette and recording silence. Circuit description The circuit diagram in Fig. 2 shows that the recor...