Noise coming from subwoofers and centre channel

Hi,

Well, I have something new, I continued my tests. Here are my findings.

I opened all the devices of my 2 channel audio system (Tambacqui, K50 and Hegel H590 complete silence.

Then, I connected the Madvr Envy video processor and nothing complete silence

Then I integrated my Hegel C55 5 channel amplifier, I only connected the center. Still complete silence. Now I integrate the arcam AVR-30 receiver, we can hear a slight electrical noise in the center channel and a slight rumble in the subwoofers.

Finally,  there it is, I connect an HDMI cable between the processor and the receiver and an HDMI cable between the receiver and my Zappiti player, the noise is really louder in the subwoofers and the center channel.

So, I understand that my problem occurs when a signal goes through the HDMI, what do you think?

Should I try a cheater plug and connect the receiver?

Thanks.

I did another test and connected my center directly into the receiver. Now the noise disappears in the center compared to when connected in the external amplifier. However, the noise is still present in the subwoofers... All my devices are connected on the same circuit, it's a circuit just for my electronic devices.

OP: 

It does sound like a ground loop is forming.  If you disconnect the video cable from your projector does the noise go away? 

Nice detective work, and at least at this point there’s a loop that involves the AVR and/or amp. If it’s me I’d try the simplest thing first that’d be a cheater plug on the AVR, then on the amp, and then on both (if necessary) and see what happens. You could also consider contacting the fine folks at Hegel as they may give you a very quick and effective solution rather than spending time/$ trying different things. I’d be interested to hear what you find.

Okay now, I removed the two HDMI cables on the processor, projector out and Zappiti player in, the noise disappeared completely. I reconnected the center to the external amplifier and there is no noise either. So it’s the video part that causes this problem. First time in 2 decades that this has happened to me...

I’m going to buy two 3 to 2 sockets, it’s not expensive.

I hope it’s not too risky to use such a socket.

I will send an email to Hegel for their opinion. thanks for the advice