Equal loudness control circuit

MOS power IC full range

Photocoupler

Figure 1-87 is a better equal loudness volume control circuit. It uses only one common potentiometer. The components used are few, but the effect is quite remarkable. The working principle of the circuit is: when the internal impedance of the signal source is much smaller than Rc, the load impedance is large and dry Rp, and Rp is much larger than the ruler I and Rz, the value taken by the capacitor C only acts on the high and medium audio. Open for low audio