No sound from JustBoom Card

I bought one of these (DAC HAT) from you in September (see post sept 21) but have only connected it to the RPi3 B+ today. I am getting no sound except for a bit of hum. I still get good sound from the RPi stereo output socket, regardless of what settings I make (justboom, analogue, digital or none selected). No sound whatever from the JustBoom RCA sockets or the headphone socket. Any ideas?


Hi John,

Did you follow the software setup instructions detailed here?

It sounds like your OS isn’t set up to interface with the JustBoom.

Let me know!

Hi Stephen,

Thank you. I now have sound, glorious sound.

There is however quite a level of hum when no sound program is active. For
example, I went on line, clicked on a site with links to SoundCloud files
(which I put there), and the moment the file starts to play, the hum
disappears. The RPi sound volume control makes no difference to it. It is
still there after the RPi is turned off, but disappears once the RPi is
unplugged from the power point (i.e. when there is no power supply
active). It may be that this is a common phenomenon with computers,
because the set-up which I am planning to have the RPi replace, sometimes
does this sort of thing.

The JustBoom DAC is advertised by Core as plug and play, and its box says
the same thing. I’m not trying to be picky, but at the very least, there
should have been information somewhere giving the link which you provided
in your email. (Perhaps there was some? - but my eyes will be 80 years old
in less than 6 months time, and I failed to see it). And like so much
internet technical information, it is not complete - the tutorial in the
link said nothing about how to save the modifications to the config.txt
file (unless I missed it). You could claim that a person not knowing how
to do that should not be using a Raspberry Pi, and that may well be the
case, but it would not have taken much effort by the person at JustBoom to
add those details.

Again, I am not trying to be critical. But you are running a business, and
ease of use for the customer does need to be high on your priorities. So
far I am very impressed with the RPi3 B+. I believe it will suit my needs
far better than much more expensive computers. I plan to buy a second one
from you, along with the 7" touch screen and the Pimoroni mount. My
project is a home Virtual Pipe Organ, and the two RPi’s will be mounted on
either side of the two keyboards. I will use the two touch screens to
control the organ stops, and one of the RPi’s will generate the stereo
sound. There is the option to have sound coming at times from both RPi’s.
I am one of the VPO developers for the free program, jOrgan. You may find
its website, which I created, of interest -

Best wishes,
John Reimer

I thought I was sending a reply to Stephen’s email. The sound files I mentioned can be accessed via the Gallery page of my website, if any people are interested.


Hey John,

Glad you got it worked out! Since this you thought this was going to my email do you want me to remove it from the forum?

In the Maker/DIY Electronics business, it’s quite common that products come without explicit directions on how to get them to work. It’s a niche where people expect to need to be able to learn/find the information needed to put things together. That said, we do provide information for setup and use whenever possible. We also have a whole section of the website dedicated to tutorials and online workshops to help you learn all the essential skills needed to get your project off the ground. We then supplement those resources with this forum, so we can help you find those resources if you need!

Sounds like a great project by the way! That hum that you hear when no audio is playing is something I’ve noticed in my Raspberry Pi at home. It comes from the power source that you are using. See if you can power the Pi from a different source. The ultimate in clear audio would be powering from a battery, but any way you can reduce the noise from the power supply will help. Alternatively you could try this:
In /boot/config.txt add the following line:

Good luck with your project!

Hi Stephen,

Thanks. You could leave it on the Forum - I didn’t actually become
unpleasant in what I wrote. And some people may find my website

I don’t think that Core Electronics is responsible for short-comings in
what comes from manufacturers, but you do need to be careful about the
wording on your website and on any other publicity material. As it
stands, I don’t think that the JustBoom is plug and play. Including the
link that you sent me would cover it. Without that information, I don’t
see how the JustBoom can work, and so you run the risk of losing a

Best wishes,

1 Like

Hi John,
I think Steve was just giving you the option to remove it as you were not aware it would be posted publicly. I can see that the product page now includes a link to the guide that Steve posted previously.