Figure 4-18 by volume potentiometer T (Xi 153AP and tone potentiometer T ( 155AP consisting of volume, tone control circuit circuit, Rx, cx clock oscillation element, the value
of which can be selected according to the desired oscillation frequency : f (Fic L/. 0.7F xCx (Hz) where Rs 3Rxo Guardian 153AP adjustment method using the attenuation levels, the total attenuation adjustment range of O-66dB, unit step attenuation amount of the attenuation level which 2dBo use 10dB attenuation amount units (corresponding to the resistance value of 50 snapped that RATT1); the second level attenuation minus 2dB units using the amount of attenuation (corresponding to the resistance value 20kfl, namely RATT2) o have the same circuit two inner lc, respectively for left and right channel use. to obtain good signal to noise ratio can be used to input RArTl, RATI2 for output. TC9155AP built two identical circuits each t is an adjustment range of 6 ~ + 6dB, the resistance value of is 100kn, sub -level 13 step adjustment, each with a set of two-channel electronic potentiometer resistor network together with an external capacitor connected to the op amp s feedback loop amplifier, tone control circuit composed of feedback operational amplifier using TA75558P also be MC1458 or other similar operational amplifier circuit.