LM1036 internal circuit schematic diagram and pin function diagram

Except for slight differences in some parameters, these two circuits have the same internal circuit structure, circuit pins and functions.
The circuit adopts dual in-line 20-pin package. Its internal principle and the functions of each pin are shown in Figure 4-21. The internal circuit is mainly composed
of an internal regulated power supply (for internal circuit use), a Zener regulated power supply (for DC control) and two sets of identical volume,
tone and balance circuits. The function of
    each pin is introduced as follows: Pin 12 is the DC volume control terminal. By changing the DC voltage of pins 1 and 2, the volume can be controlled
. When the circuit is working at a low volume, if the input signal level is too high, the circuit will be
saturated when the tone is raised, so the gain is attenuated by 15cB first, thus ensuring the normal operation of the tone volume system without saturation,
and It has a better signal-to-noise ratio when working at low loudness.
    Pin 9 is the balance control terminal. Changing the DC voltage on pin 9 can adjust the gain of the two channels and achieve
a balanced output of the two channels. When vg is low, the gain of channel 2 is large and the gain of channel 1 is small, and vice versa. When 1v9=2,7V (i.e.
V17/2), the two channels reach balance.
    Pin 4 is the treble control terminal, and pins 1 and 4 are the bass control terminal. Changing the DC voltage of pin 4 or pin 14 can
enhance or attenuate the high and low bass. 1 Pin 7 is the DC control voltage output terminal, which provides high-precision and high-stability DC control voltage (5.4±200mV)
    to the control circuit through the internal voltage stabilizing circuit .
When the control voltage on pins 49 and 14 is adjusted to half of the control voltage,
that is, 2.7V, the gains of the left and right channels are equal, achieving a balance of left and right channels, and the tone control obtains flat frequency response
characteristics , reaching a high ． , the bass neither boosts nor attenuates.