Circuit 90s common recorder head amplifier circuit, the choice of ultra low noise precision op amp OPA37 pre-formed head amplifier. Circuit can provide a standard NAB equalizat
ion. At 1kHz voltage magnification of 50dB. Audio input signals from the pick-up head means and into the noninverting input OPA37 This connection allows operational amplifier having a high input impedance, i.e. OPA37 pin 3 to ground can be approximated as an open circuit, the circuit RL, CL is the load consisting of the head impedance. The head should be used manufacturers recommended value. Circuit resistance, capacitance element should be used in high-quality metal film resistors and film capacitors organic synthesis.