| Part | Total Qty. | Description | Substitutions |
| R1 | 1 | 100K 1/4W Resistor | |
| R2 | 1 | 820K 1/4W Resistor | |
| R3, R14, R16, R18 | 4 | 2.2 Meg 1/4W Resistor | |
| R4, R5, R6 | 3 | 22K Pot | |
| R7, R8, R9, R25, R27, R29 | 6 | 10K 1/4W Resistor | |
| R10, R11, R12 | 3 | 680 Ohm 1/4W Resistor | |
| R13. R15, R17 | 3 | 580K 1/4W Resistor | |
| R19, R20, R21 | 3 | 39K 1/4W Resistor | |
| R22, R23, R24 | 3 | 47K 1/4W Resistor | |
| R26, R28, R30 | 3 | 33 Ohm 1/4W Resistor | |
| C1, C5, C6 | 3 | 0.012uF Polystyrene Capacitor | |
| C2, C9, C10, C11 | 4 | 3.3uF Electrolytic Capacitor | |
| C3, C4 | 2 | 0.0022uF Polystyrene Capacitor | |
| C7, C8 | 2 | 47nF Polystyrene Capacitor | |
| C12, C13, C14 | 3 | 0.47uF Electrolytic Capacitor | |
| C15, C16, C17 | 3 | 22uF Electrolytic Capacitor | |
| D1, D2, D3 | 3 | 1N4002 Silicon Diode | |
| D4, D5, D6, D8, D8 | 5 | Green LED | |
| D10, D11, D12, D13, D14 | 5 | Amber LED | |
| D16, D17, D18, D19, D20 | 5 | Red LED | |
| U1 | 1 | LM3900 Quad Op Amp | |
| U2, U3, U4 | 3 | AN6884 Bar Graph IC | |
| MISC | 1 | Board, Wires, Sockets For ICs | |
- The circuit expects line level inputs. If you connect it to speaker level, you will have to readjust the circuit every time you change the volume.
- After the circuit is connected, apply power and signal. Now adjust the pots until the corresponding group of LEDs reacts.
- Thanks to Alterac for correcting some errors on the schematic that originally appeared on this page. Read all about it in the 3 Channel Spectrum Analyzer Project thread in the forum.
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