The Multi Output Amplifier Power Supply provides a stable and isolated voltage rails for powering an audio amplifier along with additional modules like UBS, Pre amplifier board, decoder board and cooling Fan. The separate supply rail output pins are available to connect sub woofer amplifier, Right and left channel amplifier, USB module in this circuit.
The power supply contains
– High Current Supply for Amplifier Sections.
+/- 12V Regulated dual Supply for the Pre Amplifier and sub filter board.
Regulated 5V Output for the USB Module.
Dedicated Output for Cooling Fan .
Amplifier Power Supply Circuit
Components Required
| Section | Component | Value / Part No. | Quantity |
|---|---|---|---|
| Subwoofer Supply (24-0-24V) | C1, C2 | 4700 µF / 25–50V | 2 |
| C7, C8 | 0.1 µF | 2 | |
| D1–D4 | MUR860 | 4 | |
| J2 | 24-0-24V | 1 | |
| J4 | SUB output | 1 | |
| Main Amplifier Supply (18-0-18V) | C3, C4 | 4700 µF / 25V | 2 |
| C5, C6 | 0.1 µF | 2 | |
| D5–D8 | 1N4007 | 4 | |
| J1 | 18-0-18V | 1 | |
| J5 | AMP output | 1 | |
| Pre-Amplifier dual 12V Supply | U2 | 7812 (TO-220) | 1 |
| U3 | 7912 (TO-220) | 1 | |
| C13, C14 | 1 µF | 2 | |
| C15, C16 | 0.1 µF | 2 | |
| J8 | PRE-AMP output | 1 | |
| USB Module + Cooling Fan Supply (12V AC) | D9 | 2W10 | 1 |
| C9, C11 | 4700 µF / 25V | 2 | |
| C10, C12 | 0.1 µF | 2 | |
| U1 | 7905 (TO-220) | 1 | |
| J3 | 12V AC input | 1 | |
| J6 | Fan output | 1 | |
| J7 | USB output | 1 |
High Current Supply for Amplifier Sections
The circuit begins with two AC inputs of 24-0-24V for the subwoofer amplifier section (J2 → J4) and 18-0-18V for the main amplifier and pre-amp (J1 → J5, J8)
Each input is rectified using high speed MUR860 diode and 1N4007 or high current diodes. Large filter capacitors (4700 µF each) is used to smooth the DC output. These high current rails are suitable for powering Class-AB or Class-D amplifier boards.
Dual 12V Regulated Supply for the Pre Amplifier
The pre amp board requires a clean, low-noise dual supply. so the Regulators 7812 (positive) and 7912 (negative) is provide a stable 12V dual supply output. Additional capacitors will help to reduce the ripple and ensure cleaner audio processing. This will improving the pre amp sensitivity and overall sound clarity.
Regulated 5V Output for the USB Module
A separate 12V AC input (J3) is rectified using a 2W10 bridge rectifier and filtered with 4700 µF capacitors. A 7905 regulator then provides a stable 5V DC output, This voltage is suitable for certain USB audio modules or logic sections like decoder board that operate on negative rails.
Dedicated Output for Cooling Fan
The same rectified 12V source can also power a cooling fan, helping maintain thermal stability of the amplifier. This will helps in reduce heat during continuous high power operation.
