Building a JustBoom Audio Player

the footprint of the justboom audio player is only a fraction of an inch more than a credit card outline.

I used to wonder if smartphones will replace music players. One can, in theory, play digital music directly from my Samsung Android phone. However, it's awkward because a special adapter is required to connect the USB music signal to any downstream audio devices. This adapter interferes with a phone's armor which forces me to remove the case for each listening session and then replace it. If I tolerate that much inconvenience, then any incoming calls or notifications interrupt the music. That's like having public announcements during music listening which should be intimate and private. Thus, I was rudely reminded you can't do everything with a smartphone.

A dedicated Hi-Fi audio player perfects a computer audio system setup. Avid listeners who have substantial collections and an appetite for several musical genres, from different digital sources, won't tolerate much fumbling. So I'm delighted to find the little Raspberry Pi computer board that was designed as an educational tool has become very inexpensive and popular. The Pi's audio applications are improving computer audio profoundly for the better, not only through fantastic musical fidelity but also through easier and more convenient access to digital libraries and streams. This post describes what it was like to get a Raspberry Pi-based audio player up and running.

Good News

JustBoom, the British startup mentioned in my previous blog post, is now offering a diverse Raspberry Pi audio product line. They produce an assemble-yourself, true high fidelity audio player kit that sounds fabulous with the components I already have. My Audioengine A5+N (Bamboo) speakers sound as good as ever connected to this player's variable Line-Out. Closer comparative listening may reveal if this new component brings better musical realism across the board.

I didn't have a dedicated computer audio player before discovering JustBoom. I was complacent with using my computer or iPad 3 to source music and to control playback. Now that I've experienced the great ease and convenience a headless, dedicated digital audio player brings to the listening experience, I would not want to give up control from any device and from anywhere in the house. I'm also happy to find the available choices are capable at the low end of cost. There's no need to dig deep to buy a Mac Mini and an audio operating system. Now the computing hardware and audio devices are inexpensive and some available custom Linux-based OS distributions are free.

As long as you have the following bare essentials, JustBoom offers a path to get your digital music playing. You need to have only the following minimum of components:            

  • A control device (Mac or PC computer and/ or any smartphone or tablet that runs a web browser.)
  • A Wi-Fi enabled local data network with an available Ethernet tap on the router.
  • Stereo speakers (preferably 4 Ohm Impedance and/or very efficient, if passive.)

I like a player with diverse capability that's not limited to either powered or passive speakers. In some cases, I must work around limitation to the 30 W RMS power capacity of the JustBoom power amplifier board. Therefore, I configured a JustBoom DAC HAT board along with an Amp board to maximize the player's flexibility and cover all speakers, even if another amplifier is required.

The Build

This section describes the procedure but please don't contact me for support with your own assembly process. Support is included with your purchase. If you need help, contact JustBoom via their website if their copious help content does not resolve an issue.

The following items are essential.


  • Anti-static mat and wrist strap (not necessarily required)
  • #0 Phillips Screwdriver
  • #1 flat-blade screwdriver or similar tool
  • Tweezers or Needle-nose Pliers

  Audio Components:

  • JustBoom DAC HAT Kit, which includes:
    • Raspberry Pi 3B PC Board
    • JustBoom DAC HAT PC Board
    • Power Supply (outboard)
    • Case for DAC HAT (an added Amp PCB also fits into this Case)
    • A Micro SD memory card for the OS code
    • Required screws, spacers, and RCA interconnects
  • JustBoom Amp Board, 30 WPC Stereo, with onboard DAC chip 

Physical Hardware Assembly

I slowly worked through the online documentation to assemble the JustBoom hardware. It only took a few hours to get the whole system playing. Everything physically fit well and went together without mishap. Though picky about quality, I was pleasantly impressed with the build of the boards, cables, and the case, which are top-notch, equal to any electronics I have worked with in my engineering specialties in electromechanical systems design and product design. All the latest circuitry technology is apparent.

It is easy to followed the hardware Assembly Process that is fully documented on                                   

  • Stack the Boards
  • Insert the Board stack into the Case
  • Verify the Power Supply selection

Finishing up the physical configuration, I connected a Wi-Fi Router via Ethernet cable to the Raspberry Pi board. I also plugged a memory stick into a Raspberry Pi USB slot. This makes a portable collection if digital files available. There are six USB ports and an Ethernet port on the Pi board. That's plenty of connectivity for music library on various memory devices. SD cards or memory sticks can hold a virtually unlimited library. Or you may connect a NAS drive in your network. Online streaming is also available.

I downloaded the Volumio OS image file to my laptop and used a USB SD card flash device (bought from Amazon) to write the Linux OS distribution image onto a Micro SD card. I burned the custom OS to a Micro SD Card following Volumio's instructions:

  • Download -- retrieve the software image from
  • Flash the Micro SD card -- using downloadable Etcher software and a Micro SD USB burner

I plugged the programmed Micro SD card into the slot under the Raspberry Pi Board.


The JustBoom audio player is "headless," meaning it has no display or keyboard. You control the shiny little piano-black box either from a computer, a smartphone, or any other device with Wi-Fi that can run a browser. Spotify now works with the Volumio player app and it sounds as good as ever. When you go to the IP address of the player using a browser in your "head" device, it connects via Wi-Fi and puts you in control.

 When Volumio's player app comes up online, some player configuration settings were required. I saved the player's IP address so I can log in via my smartphone. Volumio turns your phone into anther, pocket-sized music controller, a role more suited to its nature.

Volumio has all the essential controls. Aside from being rather slow to respond at times, it left little to be desired as a basic player. However, I do miss the full functionality of the excellent Spotify user interface. No worries, though. Numerous sources are developing many more versions of control software so we'll have many options.

To listen, I pick a music source from either a memory device plugged into the Raspberry Pi or an online streaming source. Spotify is the only option, presently. I look forward to TIDAL access and to listening to my 16-bit playlist library there. It's coming, JustBoom tells me. I'm confident that TIDAL will become a viable streaming option at some point.

I have a good selection of FLAC files. Also, offers a many reference digital files that are often used to benchmark audio setups. There's actually quite a bit of high-res music available free online. Use the big black button ("Free Digital Music Files") at the top of the right sidebar on

I love this JustBoom audio player. The main thrill so far has been re-listening to my Spotify library. I easily hear new details on several very familiar selections even though the resolution is still only MP3 via Ogg Vorbis format.

Now I'm curious to explore JustBoom's truly tiny version, based on the newer, much smaller Pi Zero board. That's another upcoming project, although the footprint of this "full-sized" player is only a fraction of an inch larger than a standard credit card outline.

A Few Tips

 Be sure to carefully analyze your many options on the JustBoom Product Guide page. Find the setup that does just what you need to expand your audio system for least cost. If you only need 30 W RMS power for your speakers, you won't necessarily need to get the DAC HAT Board or a standalone DAC because the Amp Board has the same DAC chip on it as the DAC HAT Board. So does the AMP HAT board.

If you stream from online, and you're using powered speakers or an outboard amp, you have two variable volume controls. One is inside your player app. The other controls your amplifier's gain locally. Be sure to set the control inside the app, pegged at 100%, to the highest possible setting. This gives you the strongest variable line input signal with the best noise floor. If you set it lower, you may hear background noise that would otherwise not be audible. Then control your final listening volume from the external (other) volume control. You still have the full range available there.

Summing Up

So far, the apparent net gain is been one of great convenience in accessing and controlling music rather than another giant leap in musical fidelity, in my case. Musical realism had been pretty much tapped out in my system already. But I can connect a lot more local storage now via USB. My phone, iPad, and laptop computer are freed up from music serving. In listening, I definitely notice what more convenience does to enhance the whole listening experience. I'm grateful to enjoy the music even more with less distraction around music availability, selection, and no "announcements" during playback.

On the whole, my listening experience has never been better. Everything about the music sounds at least as good as before I started with JustBoom. The realism is superb and I still lose my sense of place shortly after I close my eyes and let the music carry me away to scenes found only in imagination.

I believe the DAC chip in the DAC HAT may sound a cut above the one I have become most accustomed to. The JustBoom player has much broader format acceptance than formerly available to me. How do the more extreme resolutions sound via this player? I'll keep listening and report more details and some music quality comparisons in the next post here on

-- Joseph Riden


Go to JustBoom HERE.