Noisy RPI and Dragonfly DAC

RPI4, Audioquest Dragonfly Black USB DAC to Preamp/Poweramp/Speakers.
Everything works but there is a slight audible background high pitched noise and a barely discernable tick/tick/tick noise.
The noise is there even when no music is playing.
The noise is not there on any other input - mc vinyl or cd (or at least much less prominent).
The noise is there with both Tidal or Spotify.
The noise is not there if I unplug the DAC.
Suggestions how to find the culprit??


  1. Another line level input on your preamp (unlikely to improve but needs checking)
  2. Stream a file directly from the RPI4 - unlikely to improve but eliminates Tidal/Spotify/internet as root cause
  3. use the USB on your PC to drive the DAC - again not likely that switching from the RPI4 to the PC will resolve the issue.
  4. Mains wiring to the preamp and power amp and RPI4 power brick should be directly to the same power socket block to reduce ground loops and possible resultant noise and hum issues. I would not recommend disconnecting grounds on the preamp or power amp for safety reasons.
  5. Borrow another USB DAC. The symptoms you describe are indicative of digital noise breakthrough in the DAC. I would expect that low cost pen drive DACs would be more susceptible than a desktop DAC. This sounds like the most likely cause. I use a Topping D90 DAC fed directly from the RPI4 USB and I searched for any noise issues by listening on very quiet 96/24 tracks and by measurement and none were present. But this is a much more expensive DAC.

Do not invest in USB noise cleaning filters unless you can get to try them before you part with any money or you get the option to return them if you are not satisfied that the problem is completely eliminated

Thank you. These are excellent suggestions. I will investigate.

i have 2x rpi4 / 4gb
output: dragonfly black,red,colbalt
volumio 3.015 / 3.010

btw i’m running dragonfly on 70/80 % of volume that’s seems the best settings…on the rpi

it could be the power supply i got 3 dragonfly’s and didn’t hear it yet…

I hadn’t read your initial posting very carefully. One thing I now notice is your comment that the noise is not there on any other input - mc vinyl or cd but with your caveat ‘or at least much less prominent’. If I interpret this correctly you are saying that an energised DAC plugged into your preamp actually does affect the other inputs but only to a minor extent and that this noise completely disappears when the DAC is disconnected. I imagine that the same also applies if the DAC is left connected but is unplugged from the the RPI4.

DVO reports that he is having no issues with the dragonfly black which is good news. So perhaps the issue is a very noisy RPI4 power supply? I would be a little surprised if you were hitting this problem with the standard RPI4 power brick - people have sometimes said that they can ‘hear’ differences between the standard power brick and a very high grade power supply (as in more expensive than the RPI4 itself) but what they are reporting in the main is something pretty subtle and certainly not the objectionable noise you are hearing. So it could be worthwhile to try a connection to a laptop PC USB to see whether this is quieter - preferably with the laptop mains power supply disconnected since this will be one less possible source of interference or ground loop.

i have a standaard 3 Amp brick usb-c and a ifi brick 2,5 Amp barrel jack to usb-c both sounds good

Thanks for the suggestions guys.
I found the problem…I had a Synology NAS connected to the RPI4 via USB. Unplug that USB and the noise disappears, plug it back in and the noise is back.

you can try a noise filter for your nas jitterbug ( audioquest ) is one that i know…
didn’t test mine yet … ( no noise )

Thanks. I’ll look into that.

Glad you’ve found the cause. Before buying a noise filter, try connecting the NAS via ethernet. You also will almost certainly fix the problem if you connect your RPI4 via WiFi.

@Tsar that should work too just hang your nas in to your router or some where in your network…

All done and working fine. Thanks again.