Magnetic Phono Preamp Has Ultra Low Noise Figure
This circuit is a ultra low noise magnetic phono preamp. This circuit uses an LM381/1A. This circuit also includes RIAA equalization. This circuit has ultra low noise. The DC voltage level at the output of this circuit is about 16.5V, the voltage must be equal to half of the supply voltage. That can be done by adjusting potentiometer R7. Here is the schematic diagram of the circuit:
