Availability

The new batch is ordered from the factory and is expected to hit the stock by mid-February. It will introduce the single DAC version of the board, as well as the Raspberry Pi 5 tailored dual-DAC version. New boards will be stackable, so you can build multi-channel systems using few boards combined. I also plan to reduce price, as larger volumes allow me to cut some corners.

What is it?

The Loud Raspberry Pi Hat is a cost-effective version of the Loud Raspberry Pi Home Media Center. It combines the power of the Raspberry Pi SBC and the Hi-Fi audio capabilities of the Analog Devices MAX98357A DAC.

1X	2X

Loud Raspberry Pi Hat is the same DAC and audio circuitry in a cost-efficient Hat form. 1X version can be used with any Raspberry Pi, while Raspberry Pi 5 users can use two pairs of speakers independently on the 2X version. Hat will pull the juice from the Pi's 5V line, or power the Pi itself using screw connectors, so you can make sure enough power is delivered to both boards.

Why did I build it

I did few audio projects in the past, some using ESP32, some using larger Orange Pi and Raspberry Pi devices. Each has its pros and cons, and with each iteration, I'm trying to focus on the details that were working best for me, while actually using them.

What is special about the Raspberry eco-system is of course its community support. Being a not-so-strong software developer, I often have to rely on the work that other people did and baked into the base Raspbian image. Attaching a DAC, Ethernet, and IR reader is as simple as adding 3 lines into config.txt file. All the device tree definitions, kernel drivers, and dependency packages are already in place, believe it or not.

Sure, compared to the ESP32 platform it is not as lightweight. It requires more power, it takes some time to boot. But when it comes to rapid development, there is nothing like the Raspberry Pi.

Loud Raspberry Pi Hat

Loud Raspberry Pi uses a quad MAX98357 HiFi DAC with a built-in highly efficient D-class amp to deliver 3 to 5W of music power directly to your speakers. It is not too loud, but it is very simple to use and fun to play with. It powers from a standard USB-C power source, like a phone charger, or a standard 5V wall adapter delivering a few amps.

Key features

	HiFi Raspberry Media Center	HiFi Raspberry Hat	Amped Raspberry Media Center	Amped Raspberry Pi Hat	Loud Raspberry Media Center	Loud Raspberry Hat	Louder Raspberry Media Center	Louder Raspberry Hat
Image			coming soon…
Image (2X, NOPD)
DAC	Single PCM5100A 32bit Stereo DAC	Single (1X) or Dual (2X) PCM5100A 32bit Stereo DAC	Single (1X) or Dual (2X) PCM5100A 32bit Stereo DAC working with TPA3110D2 D-Class amp	Single (1X) or Dual (2X) PCM5100A 32bit Stereo DAC working with TPA3110D2 D-Class amp	Dual I2S DAC MAX98357 with built in D-Class amp	Dual (1X) or Quadruple (2X) I2S DAC MAX98357 with built in D-Class amp	Stereo I2S DAC TAS5805M with built in D-Class amp	(1X) Stereo I2S DAC TAS5805M with built in D-Class amp(2X) Dual (2.1) I2S DAC TAS5805M with built in D-Class amp
Output	2.1 VRMS Line level output -100 dB typical noise level	2x 2.1 VRMS Line level output -100 dB typical noise level	[1X]2x 25W (8Ω, 1% THD+N) at 22V; 2x 22W (4Ω, 1% THD+N) at 16V 1x 40W (4Ω, 1% THD+N) at 20V[2X]4x 25W (8Ω, 1% THD+N) at 22V; 4x 22W (4Ω, 1% THD+N) at 16V 2x 40W (4Ω, 1% THD+N) at 20V	[1X]2x 25W (8Ω, 1% THD+N) at 22V; 2x 22W (4Ω, 1% THD+N) at 16V 1x 40W (4Ω, 1% THD+N) at 20V[2X]4x 25W (8Ω, 1% THD+N) at 22V; 4x 22W (4Ω, 1% THD+N) at 16V 2x 40W (4Ω, 1% THD+N) at 20V	2x 3W (8Ω); 2x 5W (4Ω)	4x 3W (8Ω); 4x 5W (4Ω)	2x 22W (8Ω, 1% THD+N); 2x 32W (4Ω, 1% THD+N) at 20V 1x 45W (4Ω, 1% THD+N) at 20V	2x 32W (8Ω, 1% THD+N) at 24V 1x 55W (4Ω, 1% THD+N) at 24V
RGB LED	yes	none	yes	none	yes	none	yes	none
IR input	yes	yes	yes	yes (1X), no (2X)	yes	yes	yes	yes
External relay driver	yes	none	yes	none	no	none	yes	none
Onboard Serial Bridge	yes	none	yes	none	yes	none	yes	none
Ethernet	Wiznet W5500 SPI Ethernet	none	Wiznet W5500 SPI Ethernet	none	Wiznet W5500 SPI Ethernet	none	Wiznet W5500 SPI Ethernet	none
Powers from	5V USB-C power adapter (up to 1 A) Triple LP5907 3.3 V Ultra-Low-Noise LDO	5V from the host 5x LP5907 3.3 V Ultra-Low-Noise LDO	5V USB-C power adapter (up to 1 A) Triple LP5907 3.3 V Ultra-Low-Noise LDO	8..26V from external sourcepowering host (up to 3A cont.)	5V USB-C power adapter (up to 3 A)	5V from the host (up to 4A) or 5V from screw connector (powering host)	65W USB-C PD power adapter (25W/45W with limited power)[NOPD] Up to 26V from external PSU	7..28V from external sourcepowering host (up to 3A cont.)
Mechanical dimensions (WxHxD)	88mm x 38mm x 100mm	65mm x 30mm x 15mm	88mm x 38mm x 100mm	70mm x 61mm x 20mm	88mm x 38mm x 100mm	65mm x 30mm x 20mm	88mm x 38mm x 100mm	65mm x 56mm x 20mm

Board Pinout

How to use

You need nothing more than an SD-CARD with a Raspbian image and USB-C power brick. You can use any distribution you like. The only change you need to make to enable hardware is to add 3 lines to the /boot/config.txt

dtoverlay=max98357a,sdmode-pin=5

Other software options

Project repository provides a few examples with build instructions, including Volumio setup instructions, among others.

Hardware

Please visit the hardware section of the project repo for board schematics and PCB designs. Note that PCBs are shared as multi-layer PDFs as well as Gerber archives.

PCB diagram

Image

Power considerations

Below are the power requirements for different Pi models

Consider each 5W of expected audio output to be another 1A of the current budget and buy a reasonable power source capable of delivering the sum of Pi and audio requirement with a reasonable margin of 15%+

In the extreme scenario, using all 4 channels with 4 Ohms load with Pi5 you'd need (3A [Pi] + 4A [audio]) * 1.2 = 8.4A or 42W, round up to 50W.

Raspberry Pi 5 note

Raspberry Pi 5 is the first one that allows to drive multiple I2S data lines using the same interface. What it means in practice, is that while all older Pis have just 3 I2S lines (CLK, WS, DATA), Pi5 support up to 4 Data lines (CLK, WS, D0, D1, D2, D3), capable of driving 4 independent audio interfaces.

2X Raspberry Pi hats have support for alternative data lines. You need to short some solder bridge to use it though. It allows configuring Hats to use different pins and stack them together to create 4 individual stereo interfaces (8 channels in total) using the same device.

By default, 2X hat uses pins 21,23 for data, with the possibility to switch to pins 25, and 27 with solder bridges and stack 2 boards together.

Loud Hat

The device tree that can utilize all channels and DACs on and off properly is a work in progress. But a quick and dirty way to enable all channels is to use hifiberry-dac8x device tree. It lacks enable pins and thus they need to be permanently switched on in the software.

Configuration value that allows this is quite simply

dtoverlay=hifiberry-dac8x