Sonocotta has launched the Louder Raspberry Hat Plus, an upgraded audio HAT for Raspberry Pi that swaps the original TAS5805M amplifier for the more powerful TAS5825M Class-D chip. The new board delivers up to 2x32W at 8Ω or 2x45W at 4Ω in its 1X configuration, while the 2X variant adds a dedicated 53W subwoofer channel at 4Ω. Bridge mode enables even higher mono output for single-speaker setups.
The HAT works with all Raspberry Pi models featuring a 40-pin GPIO header, including the Pi 2, 3, 4, 5, and Zero series. Audio processing runs through an integrated DSP offering 15-band parametric EQ per channel, 128-tap FIR filtering, 3-band dynamic range compression, and selectable crossovers. Digital volume and gain control provides 32-step analog adjustment, while hardware monitoring protects against overcurrent, thermal, and power supply faults. The board accepts 7V to 26V DC input and includes an onboard buck regulator that supplies 5V at up to 3A to power the Raspberry Pi itself.
Since the TAS5825M isn't supported by standard Raspberry Pi OS, users need to install a custom driver from the project's GitHub repository, which includes PCB schematics and software setup instructions. The open source kernel module has been unified to support both TAS5805M and TAS5825M chips with automatic detection based on I2C address, meaning the Plus model and original HAT share the same driver codebase. The installation typically takes about five minutes and one reboot to enable full ALSA control over volume and DSP features. The DSP is fully controllable from userspace through ALSA, providing real-time adjustment of EQ settings, crossover filters, mixer modes, analog gain, and switching frequency without requiring reboots. An infrared receiver on the 1X model connects to GPIO 17 for remote control functionality. Once configured, the board works with Volumio, Moode Audio, and Logitech Media Server. Additional documentation is available on Hackaday.
The Louder Raspberry Hat Plus is available on Tindie starting at $25 (€23) for the 1X stereo configuration and $30 (€28) for the 2X model with subwoofer support. Optional add-ons include OLED and TFT display HATs for showing album art and track information, plus a 65W power adapter. The board measures 6.5 cm (2.6 inches) by 5.6 cm (2.2 inches) and stands 2.0 cm (0.8 inches) tall.
