Hi-Fi add-on board gives Raspberry Pi HD audio
Developed with Wolfson, it is based around the audio company’s WM5102 audio hub chip which has a comprehensive set of analogue and digital audio inputs and outputs, and represents a huge quality increase over Raspberry Pi’s existing education-grade audio interfaces.
Fabless Wolfson made its name producing high quality audio chips.
Exciting for audiophiles, this particular chip is capable of 113dB signal/noise (SNR) headphone playback (29mW into 32Ω load at 0.1% THD+N), and has high-quality line out (green connector in the photo) as well as a built-in Class-D amplifier for driving small local speakers (header pins).
For recording, is also has 96dB SNR microphone inputs, and the PCB includes built-in MEMS microphones.
Line-in (pink) is also implemented.
The two phone plugs are digital (SPDIF) in (white) and out (orange).
The remaining socket is power-in.
For more basic audio – like VoIP work, there is a microphone/headset plug (black).
Software for the board is available in the element14 website, and will be rolled into a release of Raspbian – the Raspberry Pi foundation’s own spin on Linux, said element14.
Electronics Weekly has been itching to speak about this board since the middle of last year when its existence was revealed during research for the article ‘Getting Hi-Fi sound from Raspberry Pi‘, in which NXP engineer Wim Lemmers revealed how he was interfacing NXP chips to get high-quality sound out of the little computer.
Both Wolfson and NXP have used the special I2S digital audio port made available on version 2 of the RasPi PCB. The port is not populated with a header connector, and Wolfson has chosen to put spring-loaded pins on its board to avoid the need to solder to the Raspberry Pi board.
Exactly what quality will be available from this board will be up to the circuit design and the way the board has been laid out. With Wolfson involved, expect good things.
Getting Hi-Fi sound from Raspberry Pi