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PSU-1848 Power Supply Kit
Circuit Operation:
RECT1 is a bridge rectifier for the 48V section that converts the input AC voltage to DC. C1 and C2 is a filter capacitor that filters
the ripple voltage after the rectifier.
This filtered DC voltage then goes to IC1, which is a 3-terminal adjustable voltage regulator. The values for R1, R2 and R3 are
chosen so that you can achieve a +48V output. R3 is a trimmer resistor that is used for fine-tuning the output voltage.
D1 and D2 are diodes that protect the IC1 voltage regulator. C3 is added for stability, along with bypass capacitors C4 and C5.
C18 is another filter capacitor to further reduce ripple from the 48V section. Since the 48V output will be used for phantom
power, we want it to be as clean as possible to prevent the mic preamp from amplifying any ripple/hum in the supply.
RECT2 is another bridge rectifier for the split supply section. C8, C9 are filter capacitors to smoothen out the ripple. C10 and
C11 are bypass capacitors, along with C12, C13, C14 and C15. IC2 is a positive 3 terminal voltage regulator while IC3 is it’s
counterpart negative 3 terminal voltage regulator. D3, D4, D5, and D6 are protection diodes for the regulator.
Resistor values R4, R5 are chosen so IC2 and IC3 (along with resistors R6 and R7) will /-18Volts. R6 and R7 are trimmer
resistors used for adjusting the output voltage.
Resistors R8 and R9 are current limiting resistors for LED1 and LED2. You can solder LEDs to the PCB as a visual reminder if the
board is powered up. Or, you can to mount your LEDs to your front panel as a visual indicator for the (+) and (-) supply voltage.
Basic Tools Required
A few basic tools are required to build this kit.
1.
Soldering iron – adjustable temperature recommended, but not necessary. Your soldering iron must have a sharp
conical tip. I do not recommend a “flat-head, screwdriver-type” soldering iron. DO NOT USE A SOLDERING GUN. They
are usually rated at 100Watts and are overkill for this project.
2.
Mini Pliers Cutter – to cut component leads, wires, strip insulation off wires (if you don’t have a wire-stripper tool).
