Tasel

Here is the VU meter with 12 LEDs circuit. This is an easy visual indicator of the audio level signals. Can be applied to various input levels, adjusted by trimmer TR1 (state) – TR2 (Gain), then rectified by diodes D1-D2 (standard negative mark-recovery periods) and provide in the main circuit indication, consisting of the diodes D3 up to D13, transistors Q2-Q13 and materials that exist around them.

Components List
R1________________________47K
R2,R3_____________________1M
R4,R7_____________________1K
R5________________________100
R6________________________18K
R9,R11,R13,R15,R17_________560
R19,R21,R23,R25,R27________560
R29,31____________________560
R8,R10,R12,R14_____________4K7
R16,18,20,22________________4K7
R24,R26,R28,R30____________4K7
C1,C5_____________________10uF/25V
C2________________________100nF/100V MKT
C3,C4_____________________4.7uF/25V
C6________________________47uF/25V
C7,C8_____________________100nF/100V
TR1_______________________100Kohm Trimmer
TR2_______________________4.7Kohm Trimmer
LD1 until LD7_______________LED Green
LD8,LD9,LD10______________LED Yellow
LD11,LD12,LD13____________LED Red
D1 until D13________________1N4148
Q1 until Q13________________BC550C – BC549B
IC1_______________________TL071
IC2_______________________7812 [With Heatsink]
All Resistors is 1/4W 1 -5%

[source:Otenet]