The best approach with this problem is to upgrade the OS to the latest kernel.
To upgrade your system use the following commands from a shell terminal:
sudo apt-get update
sudo apt-get dist-upgrade
Restart the OS and your JustBoom card should be available for you to select.
Note: The problem behind this is that only very recent versions of the kernel support our boards and upgrading is by far the easiest way of fixing the issue.
My JustBoom isn’t recognised by the OS I am using
Some OS will not configure the JustBoom cards without some additional configuration.
Generally it will be a question of adding two lines to the config.txt under either /boot or /flash
For DAC and Amp cards: dtparam=audio=off dtoverlay=justboom-dac
For Digi cards: dtparam=audio=off dtoverlay=justboom-digi
save, reboot and you should be able to select your JustBoom card within your distro preferences.
Note that if there already is a line dtparam=audio=on you should comment it out with a # at the beginning.
My JustBoom Zero board is not playing despite all the software being properly configured
The JustBoom Zero boards can be used with stacking headers or installed directly on the Raspberry Pi Zero. Some stacking headers and some 2x20 male headers on the market though are too thin or too short to provide good contact with the board.
If you are using stacking headers make sure that the pins are squared and are at least 0.6mm in width. If you are soldering the 2x20 male header on the Raspberry Pi Zero make sure that the pins are 0.6mm in width and 6mm in usable height.
Which are the Inputs and which the Outputs on Amp and DAC?
The Inputs and Outputs of the JustBoom DAC and the JustBoom Amp are clearly highlighted in the picture. Please bare in mind that should you combine the two together you can always used the micro USB power input unless you are connecting passive speakers to the Amp. In this case refer to this document which clarifies the specs of the power supply to be used depending on which speakers will you use.
Note: The Input on the Amp is intended to be a Line In type of signal and it is only available when the Amp is used on its own. Do not use this screw terminal when the Amp is stacked on top of the DAC or the DAC HAT.
Note: The polarity of the screw terminal block for the Output on the Amp is also reported in the picture.
What PSU do you recommend for the JustBoom Amps?
We will be listing a few PSU choices on our online shop fairly soon but in the meantime you can choose from this selection:
What are the sampling frequencies and the bit depth supported by the JustBoom cards?
Sampling Frequency (KHz)
Justboom Amp HAT
Justboom DAC HAT
Justboom Digi HAT
Justboom Amp Zero
Justboom DAC Zero
Justboom Digi Zero
Please bare in mind that some OSs will not allow 24 bit decoding. The majority of today's Linux Kernels are configured for 16 bit and 32 bit only.
How do I add a header on the DAC HAT so that I can still use the standalone Amp?
The JustBoom DAC HAT comes with the possibility to install a header to replicate the GPIO of the Raspberry Pi. The header can be installed on P2 and can be installed in a standard fashion with it being soldered on the bottom side of the board with the pins made available from the top.
This approach although valid will preclude the installation of the optional standalone Amp. In order to solve this you can install a right angled header by soldering it from the top of the board and with the pins sandwiched between the Raspberry Pi and the JustBoom PCB as shown in the picture.
Routing the GPIO pins in this way can be confusing as the pin numbering is somewhat reversed from one might expect at first glance. We have added a pinout to this picture to help you work out which pin is which.
Note: This configuration can be helpful even when installing a rotary encoder. The pinout reports the default setup of our rotary encoder script.
How many JustBoom products are there?
There are 8 JustBoom products. Read more about them by clicking on the product links below.