Raspberry Pi has revamped many of its audio add-ons, replacing the previously black PCBs of the HATs with green ones to match the SBCs they’re paired with. There are a few minor layout and connector alterations too, but otherwise, the boards remain functionally unchanged. In a blog post (opens in new tab), Raspberry Pi-maker Eben Upton explained what’s going on.
The audio HATs sit on top of a Raspberry Pi (opens in new tab) board with GPIO, such as the Raspberry Pi 4 (opens in new tab), connecting to its GPIO pins and adding high-quality amplifiers, DACs, and phono outputs. IQaudio was founded in 2015 to create better quality sound products for Raspberry Pi boards used for things like streaming audio in stores and other businesses. However, it was absorbed into Raspberry Pi (opens in new tab) in 2020.
While the Raspberry Pi 4 can output sound via Bluetooth, its HDMI outputs, and a 3.5mm headphone jack, the audio HATs improve on this. The smallest is the Codec Zero (opens in new tab), which features a 24-bit 96kHz Dialog Semiconductor DA7212 DAC, a built-in microphone and external microphone input socket, a mono speaker terminal, and stereo input and output channels. It’s useful for projects like walkie-talkies and smart doorbells. Or for the amusing chatterbox the Raspberry Pi team built in the video above.
The DigiAMP+ (opens in new tab) holds a Texas Instruments TAS5756M stereo amplifier and stereo speaker outputs. It requires its own external power source but will also supply power to your Pi board. If you want to turn your Pi into a hi-fi system, this is the one to choose. There’s also a pair of DAC boards: the DAC+ (opens in new tab) and the DAC Pro (opens in new tab). They both have headphone amplifiers and sockets, but the DAC Pro adds a balanced/differential output in parallel to the line out.
The new boards are made in the UK but are available worldwide from approved resellers. Any layout changes aim to make the boards simpler and quicker to manufacture, and the only significant difference is that the PCBs are now green. Raspberry Pi has a specifications comparison document (opens in new tab) to help you choose which audio board best suits your needs.