Typical recording equalization amplifier circuit

Typical recording equalization amplifier circuit

Balanced amplifier circuits are widely used in electronic products such as recorders . When the recorder is recording, the high-frequency signal must be greatly improved to compensate for the high-frequency loss during the recording process of the magnetic head
; when playing back, since the output of the playback head is proportional to the frequency, the low-frequency output
is weak , so It is necessary to significantly compensate the low-frequency part, and the compensation circuit here is called a balanced amplifier circuit.
    Figure 9-9 shows a typical recording equalization amplifier circuit . The preamplified recording signal is sent to
the base of the recording equalization amplifier VT1 through the potentiometer (5 kQ). The amplified signal is output from the collector, and then sent to the recording head through the coupling capacitor, bias magnetic blocking circuit and recording and playback switch.
The high-frequency boosting circuit is located in the emitter circuit of VT1, using an LC series resonant circuit connected in parallel with the 1.2 kfl resistor, so that the highest
gain of VT1 is at the LC resonant frequency, which is used to compensate for the high-frequency loss during the recording process. The blocking circuit prevents the bias signal from affecting the collector
bias of VT1.