Designed by jharwinbarrozo

Original project on Flux: https://www.flux.ai/jharwinbarrozo/high-fidelity-class-d-audio-amplifier-5qbft~ht0

Why this amplifier IC: https://www.flux.ai/jharwinbarrozo/high-fidelity-class-d-audio-amplifier-5qbft~ht0/files/why-the-tpa3116d2dad~ab

Block diagram: https://www.flux.ai/jharwinbarrozo/high-fidelity-class-d-audio-amplifier-5qbft~ht0/files/comprehensive-block-diagram~8b

WHAT IS THIS PROJECT ABOUT?

This is a compact Class-D audio amplifier board designed by jharwinbarrozo. It is built around the Texas Instruments TPA3116D2DAD and delivers 50 W in stereo, or 100 W as a single mono channel when configured in PBTL mode. It takes an analog audio signal on RCA inputs and drives passive speakers directly, so it works with a phone, DAC, computer, mixer or preamp as the source, and it needs only a small number of external components.

The board also includes SpeakerGuard DC protection. The amplifier IC monitors its outputs for DC faults and shuts down automatically before a DC condition can damage the connected speaker, with no external relay or protection circuit needed.

WHY WAS IT BUILT?

The creator's motivation is simple: most amplifier modules sold online are black boxes. They work, but you cannot see why, and you have nowhere to go when you want to change something. This project is the opposite. It is a practical, high-power, analog-input amplifier, small enough for a desktop enclosure and capable enough to drive real speakers, and it is intentionally open to modification. You can change the gain, rework the input network, redesign the speaker terminals, plan your own thermal strategy or build your own front panel.

The TPA3116D2DAD was chosen because it offers the most complete set of built-in device and speaker protection features among the parts the creator compared, and because it is well documented and available at low cost through PCB, mainstream distributors. The full comparison is here: https://www.flux.ai/jharwinbarrozo/high-fidelity-class-d-audio-amplifier-5qbft~ht0/files/why-the-tpa3116d2dad~ab

HARDWARE DESIGN

• Amplifier IC: Texas Instruments TPA3116D2DAD stereo Class-D amplifier
• Output power: 50 W stereo, or 100 W mono in PBTL mode
• Inputs: analog stereo RCA inputs for left and right audio
• Outputs: bridge-tied speaker outputs on screw terminal blocks
• Power: external PVCC supply through a terminal block
• Output filtering: LC filtering on all four half-bridge outputs
• Switching-edge control: snubber networks to tame ringing
• Protection: SpeakerGuard DC protection
• Supply: bulk and local supply capacitance around the amplifier power rail, plus bootstrap capacitors for the high-side switching stages
• Configuration: jumpers for gain, modulation, mute and shutdown, and mono or stereo behavior
• Debugging: fault and control signals broken out in the schematic
• Mechanical: mounting holes and enclosure-minded geometry
• Board construction: four-layer (top, two inner layers, bottom)

Around the amplifier IC are the parts that make a Class-D design behave like an audio product and not just a noisy power switch: input coupling, output inductors and capacitors, bootstrap capacitors, decoupling, snubbers and configuration resistors.

SIMULATION AND VALIDATION

The creator has published two validation pages with the project:

Operating-mode quiescent current: https://www.flux.ai/jharwinbarrozo/high-fidelity-class-d-audio-amplifier-5qbft~ht0/files/tpa3116d2dad-quiescent-current-simulation~tb

Gain accuracy validation: https://www.flux.ai/jharwinbarrozo/high-fidelity-class-d-audio-amplifier-5qbft~ht0/files/tpa3116d2dad-gain-accuracy-validation~s6

PROJECT STATUS

The design is described as a working hardware direction, and the creator has published a video of it running. The schematic covers the main amplifier, analog inputs, output filtering, snubbers, configuration jumpers, power input and speaker outputs. The creator has also shown a 3D-printed enclosure with a separate body and top lid.

Still to come, according to the project notes: clearer configuration documentation, validated mono-mode instructions, test data, and a polished enclosure build. The manufacturing guide is a work in progress, although the Gerber and assembly files below are already published.

WHO IS IT FOR?

Builders, students, hackers, speaker tinkerers and enclosure designers, and anyone who has looked at a cheap Class-D module and wanted to understand and modify it. It is meant to be a strong, readable starting point, not the final word in audiophile design.

SAFETY

Please read the creator's safety and bring-up notes before first power-up, and check the TPA3116D2DAD datasheet for the supported supply voltage and speaker impedance: https://www.flux.ai/jharwinbarrozo/high-fidelity-class-d-audio-amplifier-5qbft~ht0/files/safety-and-bring-up-notes~hn

MANUFACTURING FILES

The project is published ready for fabrication and assembly. It includes a complete Gerber set covering top, bottom and both inner copper layers, solder mask, solder paste, silkscreen and board outline, together with an Excellon drill file, an IPC-D-356 electrical test netlist and a pick-and-place CSV for automated assembly. Bills of materials are provided in formats prepared for several manufacturers, including a version optimised for PCBWay.

CREDITS

Designed by jharwinbarrozo (Flux). The TPA3116D2DAD and SpeakerGuard are Texas Instruments products. All design work and credit belong to the original creator. Please visit the original Flux project, explore the design in full, and show the creator some support.