MOFI-20W Class A Power Amplifier DIY KIT & Finished Board

DIY KIT Project

To complete this project, high level knowledge of electronics and rich experience in terms of soldering and testing are required.
Due to time zone and language communication restrictions, we can only provide limited technical support, and you need to solve problems by yourself.
We do not provide information other than the product introduction page.

MOFI-20W Class A Power Amplifier DIY KIT Project

Tech highlights:

Fully Discrete.

20W Class A.

Monarual design.

single-point grounding, ground resistance is close to the 0.02 ohm, low noise design.

PCB is small and flexible, very friendly for all kinds of chassis installation.

More cost-effective sound modification potential.

Maximum input voltage：2.8VPP

Gain: 15X

input resistance: 1M

Output Power: Class A 20Wate 8Ω

Recommend to use CRC filter after rectifier

Product configuration

DIY kit: Contains the PCB and the components needed on the PCB.

Finished board: Based on the well-tested board on the standard version kit, we verified all key points' voltage, and used the signal generator and oscilloscope for analog waveform double verification. We will not use this board for listening test.

All finished pcbs are all carefully hand-soldered and fully tests, so the price is higher and less cost performance. Price-sensitive consumers but with have DIY ability are recommended to choose the kit

DIY KIT Instructions

Since the PCB holes are plated through, you only need to solder the parts from the bottom of the board. Do not drill or enlarge the holes because that would damage the through-plating.

Clean both sides of the blank PCB with paper towel and isopropyl alcohol or electronics flux remover, then solder the components to the board, starting with the lowest profile parts.

Make sure the correct part goes into each position on the circuit board. Measure each resistor with your multimeter to ensure it's the proper value.

Clean up the solder flux residue from the board with isopropyl alcohol (or electronics flux remover) and a brush.

Inspect all solder connections carefully, using a magnifying glass, to make sure there are no solder bridges or cold solder joints. Use a multimeter in ohms scale to check for short circuits. As a minimum, you should verify that the V+ and V- DC inputs are not shorted to ground, or to each other, and that the output pad isn't shorted to ground. Correct any mistakes before proceeding to the next phase.

Tips:
please prepare external heatsink.

Adjust 1K-VR clockwise to the maximum resistance value before powering on.

After power-on, slowly adjust 1K-VR counterclockwise until 0.36V can be measured between A-B&C-D.