Hi everyone,
I’m experiencing a serious and potentially dangerous audio issue on my Fairphone 6 when using an external USB-DAC (FiiO KA3).
I would like to check if other users can reproduce this, and whether this is already a known issue.
Device & Software
Fairphone 6
OS version: FP6.QREL.15.151.0
USB-DAC: FiiO KA3 (newest FW)
Happens with or without a charger connected — charging state does not affect the issue
Tested with different USB-C cables and different headphones
Description of the issue
When plugging in the USB-DAC and starting audio playback, the Fairphone sometimes outputs an extremely loud, distorted, full-scale noise (0 dBFS static/buzz).
The volume is far beyond any normal safe level — it is loud enough to be physically painful and could easily damage hearing or headphones.
It does not happen every time, but sporadically (maybe 1 out of 10–20 times).
After unplugging and re-plugging the DAC, audio works normally again.
When does it happen?
The issue is unpredictable, but it tends to occur:
shortly after plugging in the DAC
when the audio app initializes output
right when playback begins
regardless of whether the phone is charging or not
regardless of the cable used
It appears to occur during the early USB-audio initialization phase, before the system applies the correct volume settings.
What I’ve tested
Different apps (Amazon Music, system player)
Different USB-C cables
DAC with and without external power
Playing audio immediately vs. waiting a few seconds
Manually lowering volume before plugging in
Various headphones
Rebooting device
The behaviour is random, but it only happens on the Fairphone 6.
On other devices (Samsung, PC, etc.), the DAC works perfectly.
Why this bug is concerning
permanently damage headphones
cause hearing injury
make the phone unsafe to use with external DACs
This is one of the more serious audio-related bugs I’ve encountered on any Android device.
Request
I would like to know:
-
Can other Fairphone 6 users with a USB-DAC reproduce this issue?
(Not just FiiO — any USB-audio interface may be affected.) -
Is this already a known issue internally at Fairphone?
-
Should I submit this to the official Issue Tracker as well?
If needed, I can provide more Information and perform further tests.
Thanks in advance — and please let me know if you experience the same behaviour!