Low noise pre-equalization circuit

Figure 3-16 is a low-noise pre-balanced playback circuit composed of HA12017 . In the circuit, R3, R4 and C4 form a balanced network
that meets the maggot standard . The circuit gain of this stage is 38 - 7dB (1kFk), the output signal of the magnetic head is -65.7 ￡噼 (1kH), and the output level of the pre-equalization circuit is -27dBo. This is for most power It is not enough for the circuit, so a voltage amplification stage with 20dB amplification capacity needs to be added to make up for its shortcomings. This amplification stage can use TL072, TL082 and NE5532.     HA12017 is not only suitable for the pre-equalization circuit of tape recording and playback, but also suitable for the RIAA pre- equalization circuit of electromagnetic record players . At this time only the RC network needs to be changed .