| 摘要 |
PURPOSE:To eliminate the effect of a bias oscillator to an automatic recording gain control circuit by providing an emitter follower circuit between a recording head and the output side of a recording amplifier containing an automatic recording control circuit which controls the output level. CONSTITUTION:The output side of a recording amplifier 2 is connected to the base of a transistor TR12. Then the collector of the TR12 is connected to a power supply; while the emitter of the TR12 is connected to a recording equalizer circuit 6 via a capacitor 14. Furthermore a resistance 15 is connected between the base and the collector of the TR12 together with a resistance 16 connected between the emitter and the earth. In such a constitution, the bias current supplied from a bias oscillator 10 is cut off by the TR12. Thus no effect is given at all to an automatic recording gain control circuit 3. This eliminates completely the conventional fine adjustment of a coil. |
