Public Address System Schematic

flux

For a real MH-M18, R is the right-channel audio output.
Where R should be connected
It depends on whether your amplifier is mono or stereo.
In your current mono LM386 design
Your amplifier U1 is a single-channel amplifier, so the simplest choice is:

Table

MH-M18 pinConnect to
RLeave unconnected
Use only:
  • L -> C1 -> U1 input
  • GND -> circuit ground
If you want both left and right audio in the mono speaker
Do not connect R directly to L.
Instead, mix them to mono with resistors, then feed the mixed node through C1 into U1.
Based on the MH-M18 document
The file states:
  • pin 5 = L left channel output
  • pin 6 = R right channel output
  • pin 4 = GND is the audio signal ground
  • the module can wire L / R / AGND to an amplifier input
Recommended answer for your schematic
For your present PA circuit:
  • R should be left unconnected
  • L should drive the LM386 input
  • If you want stereo-to-mono summing, I can help you update the schematic properly with a resistor mixer first.
Mono mixer values
Check MH-M18 pins
Add stereo-to-mono
Verify input coupling
GND
C2
Capacitance
220uF
U1 GND - C5 P2
U2
C1 P2 - U1 +INPUT
J1 POS - U1 VS
C5
Capacitance
10uF
U1 GAIN_2 - C3 P2
J1 POS - U1 VS
C1
Capacitance
10uF
U1 VOUT - C2 P1
U1 GAIN_2 - C3 P2
J2 3 - C1 P1
J1 POS - U1 VS
U2 OUT - C5 P1
GND
U2 OUT - C5 P1
C2 P2 - SPK1 ~
U2 OUT - C5 P1
C3
Capacitance
10uF
GND
J2 3 - C1 P1
C1 P2 - U1 +INPUT
U2 OUT - C5 P1
U1 GND - C5 P2
U2 OUT - C5 P1
U1 GND - C5 P2
U1 GAIN_1 - C3 P1
J2 3 - C1 P1
C4
Capacitance
10uF
GND
U1 VOUT - C2 P1
C2 P2 - SPK1 ~
J1 POS - U1 VS
J2 3 - C1 P1
U2 OUT - C5 P1
U1 GAIN_1 - C3 P1
U1 GND - C5 P2
J1
J2
SPK1
U1
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Public addressing system thumbnail
Welcome to your new project. Imagine what you can build here.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$2.57–$2.91

Digi-Key

$2.78–$3.30

LCSC

$2.96–$3.09

Mouser

$6.19

TME

$1.07

Verical

$2.40–$3.17

Controls