As shown for the OPA37 constitute a low-noise preamplifier. Input signal is applied OPA37-inverting input (pin 3), circuit RL, CL is the load impedance electromagnetic pickups,
its resistance and capacity to follow depending on the characteristics of the pickup (pickup based on general parameters recommended by the manufacturer choice of). Figure in all resistors should use metal film resistors (1% accuracy), its capacitance should choose organic film capacitors. When the input signal is 1kHz, the gain is about 100 times.