being kept at the nominal 0.01 µF. These values naturally

modify the bass tone response as in

Figure 2 and Figure 3.

With pins 7 (loudness) and 12 (volume) directly connected,

loudness control starts at typically −8 dB volume, with most

of the control action complete by −30 dB.

Figure 10 and Figure 11 show the effect of resistively offset-

ting the voltage applied to pin 7 towards the control refer-

ence voltage (pin 17). Because the control inputs are high

impedance, this is easily done and high value resistors may

be used for minimal additional loading. It is possible to re-

duce the rate of onset of control to extend the active range to

−50 dB volume control and below.

The control on pin 7 may also be divided down towards

ground bringing the control action on earlier. This is illus-

trated in

Figure 12, With a suitable level shifting network be-

tween pins 12 and 7, the onset of loudness control and its

rate of change may be readily modified.

DS005142-11

FIGURE 8. Loudness Compensated Volume

Characteristic

DS005142-12

FIGURE 9. Loudness Compensated Volume

Characteristic

DS005142-13

FIGURE 10. Loudness Compensated Volume

Characteristic

DS005142-14

FIGURE 11. Loudness Compensated Volume

Characteristic

DS005142-15

FIGURE 12. Loudness Compensated Volume Characteristic

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