This is one of many audio level indicator circuit. The different is that this circuit should be connected tho the output of amplifier while the other indicators connected before amplifier module. This circuit will show the real audio output by LED indicator level.
R1_____________220R 1/2W Resistor R2,R5,R6,R8____100R 1/4W Resistors R10,R12,R14____100R 1/4W Resistors R3_____________220R 1/4W Resistor R4,R7__________330R 1/2W Resistors R9_____________560R 1/2W Resistor R11____________820R 1/2W Resistor R13______________1K2 1/2W Resistor D1___________1N4004 400V 1A Diode D2,D4,D6__BZX79C2V7 2.7V 500mW Zener Diodes D3,D5,D7,D8,D9,D10 Red LEDs (Any dimension and shape) (See Notes)
- The output power indicated by each LED must be doubled when 4 Ohms loads are driven.
- The circuit can be adapted to suit less powerful amplifiers by reducing the number of LEDs and related voltage dividers.
- LEDs of any dimension can be used, but rectangular shaped devices will be more suitable to be compacted in bars or columns.
- For a stereo amplifier, two identical circuits are required.