I have a Pi4 with a Digi+ Pro HAT in a Metal Case (all ordered through HiFiBerry.com) hooked up to a Denon PMA-A110 with a coaxial cable.
I'm using the standard Pi Power Supply and installed RoPieee using it as a Roon Endpoint.
The coax cable used is a shielded cable from Oehlbach.
When I turn on the lights (mainly LED) in the house the music stops for 1-2 seconds and then picks up again.
When connected to the Denon DAC through USB I have no issues.
Neither feeding the Pi with WiFi or Ethernet cable makes a difference.
Has anyone a clue what's wrong and/or could be changed?