Hum from Fibre Optic HDMI

Jai426

Novice Member
Hi all, hoping someone can help. I have a home setup with a JVC x7900 projector linked to a Denon AVR X4500 home cinema amp via 15ft of Fibre Optic HDMI (RuiPro). This drives am Atmos setup perfectly fine with no issues. The setup is also connected to my LG OLED and Pioneer UDP both normal non-fibre HDMI. However, I have a Roksan Kandy K2 BT that I wanted to introduce to the setup. The idea being that I can listen to Music via the Roksan, using the HT bypass.

When connected, music sounds fine on the Roksan, and movies sound fine via the Denon/Roksan when watched on my TV, however when I connect to the projector I get a hum through all speakers which only goes if the projector is disconnected. I have tried all other connections. Projector is on the same circuit. Only thing I can think is that the small active circuitry in the Fibre HDMI is causing some sort of feedback? Has anyone experienced this? I've seen a few threads that sound similar regarding fibre HDMIs but they all come back to using a hum destroyer or other ground loop fix that is not Fibre HDMI related and my understanding is that most of the solutions compromise the audio quality? Is there a known method for grounding a fibre optic HDMI etc.?

Appreciate any advice.
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Your Hybrid Fibre HDMI Cable retains copper cores to carry the Comms between the Source and the Sink which also creates an earth loop.

Is you projector double insulted or does it have an earthed mains?

Joe
 

Jai426

Novice Member
Hi Joe, thanks for coming back to me, it is earthed and part of the same circuit as both amps.
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Try simplifying the system to 1 x Source > AVR > Hybrid Fibre Cable > Projector and see if you still have the Hum or not; you can then try adding devices and identify when the ground loop is introduced.

Joe
 

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