JustBoom Digi HAT for the Raspberry Pi

The JustBoom Digi HAT is a high resolution digital audio output add on board for the Raspberry Pi. Simply stack the plug-and-play add on board (HAT) onto your Raspberry Pi and it will be ready to use immediately. The JustBoom Digi HAT produces an unmodified, high quality, digital audio data stream for bit-perfect transmission to your hifi system.

We've designed the JustBoom Digi HAT to be simple to install and use. With no soldering required and all the mounting hardware already provided this product is suitable for absolute beginners and seasoned professionals alike. Just connect your Digi HAT to an external DAC or amplifier/amplified speakers and you can be up and running quickly, enjoying flawless high quality audio playback within minutes of setting up this Raspberry Pi HAT. We also include an optional IR receiver to allow remote control operation of your Raspberry Pi.

The JustBoom Digi HAT Includes a 192kHz/24 bit digital audio chip with low jitter, bit perfect digital output (S/PDIF) over optical or coaxial connectors for an uncompromised high quality audio experience. The JustBoom Digi HAT includes an output transformer for full galvanic isolation between your Raspberry Pi and your DAC on the coaxial output. The HAT uses the I2S interface for its audio input which reduces CPU load on the Raspberry Pi compared to USB solutions.

It is also powered directly from the GPIO header so no extra cables or power supplies are required to connect to the Raspberry Pi. All of the Raspberry Pi GPIO pins are still accessible on the Digi HAT for easy customisation of your project - add additional sensors, buttons, LEDs, rotary encoders or anything your heart desires. Need help understanding how this product works? Follow product guide.

Setup Guide

• Follow full setup guide for assembling your JustBoom Digi HAT and Case.
• Configure the JustBoom Player software.

Use cases

Pairing the Raspberry Pi with a high-quality digital audio add-on board provides the perfect solution for a number of exciting projects and applications where the standard onboard audio on the Raspberry Pi simply won't cut it. Here are some possible use cases for the JustBoom Raspberry Pi Digi HAT and your Raspberry Pi computer:

• Circumstances where you need to have your streaming audio player (Raspberry Pi in this case) located separately from your amplifier or DAC. This method is usually superior to analog since the original digital signal is maintained until the amplification step (theoretically leading to less degradation of the sound).
• Streaming (either from cloud or local network) high-definition audio player
• Multi-room audio player
• Surround sound for media centre / set-top box applications
• And many many more.

Features

• Dedicated S/PDIF output interface chip supports up to 192kHz / 24bit resolution
• Digital audio output over either optical (TOSLINK) or coaxial (RCA electrical) connectors
• Low jitter, bit perfect digital output
• Output transformer for galvanic isolation
• Plug and play compatibility for ease of use
• Software volume control from your Raspberry Pi
• No soldering required
• Powered by the Raspberry Pi GPIO header
• Compatible with Raspberry Pi Zero and Pi Zero W (and also compatible with the Raspberry Pi A+,B+, 2B, 3B, 3B+, 4B (and also compatible with the Raspberry Pi Zero, but we would recommend the JustBoom Digi Zero for this purpose), and any Raspberry Pi with 40 GPIO pins 
• Mounting hardware included
• Optional IR receiver included in package
• All Raspberry Pi GPIO pins still accessible via 40pin unpopulated extension header
• Fully HAT compliant
• Full driver support in Raspbian / NOOBS
• Compatible with JustBoom Player / OSMC / RuneAudio / Volumio / Moode / PiCorePlayer / PiMusicBox / OpenELEC and others

Technical Information

• WM8804GEDS S/PDIF Transceiver with 24bit/192khz and has an integrated low jitter PLL (50ps RMS)
• DA101JC high bandwidth digital output transformer for galvanic isolation on electrical (coaxial/RCA) output
• Integrated EEPROM for automatic Raspberry Pi devicetree driver configuration and fully HAT compatible
• Digital signal output over S/PDIF with either optical (TOSLINK) or coaxial (RCA) connectors
• We recommend that if you are using the coaxial/RCA output that you connect the cable shield to the ground on the DAC / amplifier you are using and make sure that the DAC / Amplifier is using a power supply with the ground pin connected. This will help to reduce noise.
• Bit perfect digital audio transmission
• Optional Vishay TSOP4838 IR receiver included in package (solder yourself if required), Also possible to use Vishay TSOP4938 or TSOP4138 or TSOP34338SS1F
• While the hardware is able to output DTS/Dolby Digital, the Raspberry Pi software is not currently able to support this. Let us know if you want to implement this and we will do our best to help