High quality stereo pre amplifier with a IC LM3900
This simple preamp circuit consists of 4 nor ton op-amps contained in IC No-LM3900. It is a high quality stereo pre amplifier system for Magnetic cartridge.
The IC1 is connected in any way inverting mode, the input signal from the cartridge through a capacitor C1 and resistor R1 to feedback input form, The resistance R1 determines impedance input of the circuit.
The resistors R5 and R6 set the gain medium of a first sector.While the network R3, R4, C2 and C3 to get the equalizer RIAA needed. From here the signal through the equalizer is into the network to control the bass treble of sound baxendall from at IC1.
Total distortion of the circuit less than 0.1% and S / N ratio of about -67 dB unweighted, ref 500 mV out.