Вот что говорит даташит на LM по поводу муте.
MUTE MODE
The muting function of the LM4766 allows the user to mute
the music going into the amplifier by drawing more than
0.5 mA out of each mute pin on the device. This is accomplished
as shown in the Typical Application Circuit where the
resistor RM is chosen with reference to your negative supply
voltage and is used in conjunction with a switch. The switch
when opened cuts off the current flow from pin 6 or 11 to
−VEE, thus placing the LM4766 into mute mode. Refer to the
Mute Attenuation vs Mute Current curves in the Typical Performance
Characteristics section for values of attenuation
per current out of pins 6 or 11. The resistance RM is calculated
by the following equation:
RM £ (|−VEE| − 2.6V)/Ipin6
where Ipin6 = Ipin11 ³ 0.5 mA.
Both pins 6 and 11 can be tied together so that only one resistor
and capacitor are required for the mute function. The
mute resistance must be chosen such that greater than 1 mA
is pulled through the resistor RM so that each amplifier is fully
pulled out of mute mode. Taking into account supply line fluctuations,
it is a good idea to pull out 1 mA per mute pin or
2 mA total if both pins are tied together.
Тут вроде как говориться про подачу положительного сигнала на 6 и 11 ноги микросхемы.