Ultimate HDMI Cable Noise Test

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Dec 19, 2018, 12:03:45 PM12/19/18

In this HDMI cable noise test the following was done:

PC connected to power box.
Monitor connected to same power box.
Receiver connected to same power box.

Powerbox connected to wall socket (no earth grounding/wire)

PC <- VGA cable -> Monitor
PC <- USB cable -> Keyboard
PC <- USB cable -> Mouse
PC <- HDMI cable -> Receiver
Receiver <- analog cables -> Speakers

Everything else disconnected.

The test was recorded on video/audio and placed on youtube:

HDMI cable noise test video:


During this test a very clear NOISE signal can be heard coming from the HDMI cable when the PC is ON.

When the PC is OFF and/or disconnected there is no NOISE signal.

I think this video is very clear evidence that there is some kind of NOISE signal being transmitted across this HDMI cable.

Perhaps friday I may repeat this test with a high quality/expensive HDMI cable to see if it makes any difference. (If the other person agrees to provide this cable).

What is the source and why is there noise ?

I think it might be the excessive voltage/power being dumped on the chasis by the PC's power supply since it's not grounded and entering the HDMI cable connectors/plugs.

Let me know your thoughts, do you still believe it's a ground loop ?

Do you still believe HDMI cables are not capable of transmitting noise ? ;)

Also an analog cable noise test was done as well, different kind of humming noise, but also coming from PC.

Analog cable noise test video:


One question could be: Why is the humming different for analog ? My hunch is it's the receiver's analog inputs, it's being noise-filtered or so, but apperently it does not do the same for HDMI. Perhaps an oversight in the DENON manufacturer's design, believing HDMI does not transmit noise, just speculation though, it could also be the Creative X-Fi Elite Pro 7.1 soundblaster filtering out these signals before transmission over analog cables.

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