REL T/ 9 x humming issue

[sergekouthon]

Hi everybody,

I'm new to this forum and I'm not familiar with the rules.

Approx. 2 years ago, I bought a Lyngdorf MP 60 2.1 sound processor and paired it with an ARCAM PA-720 amplifier.

Last year, I replaced my old Cabasse Eole 2.1 with five Cabasse (Baltic 5) speakers.

Lately, I've bought two REL T 9/x subwoofers and two REL Bassline blue cables to address the lack of subwoofers. I've attached them to my ARCAM and followed the REL recommendations.

I followed the guidance in https://relsupport.zendesk.com/hc/e...49588-How-do-I-stop-my-subwoofer-from-humming to resolve the humming noise issue. I bought two male RCA connectors to link the REL T/9 x LFE entries of each subwoofer to the RCA entries of my Lyngdorf (entries 6 and 8 of the MP 60 User Manual).

I am still experiencing residual humming and I am yet to find a solution to this issue. Tell me the best approach to follow.

Thanks.

 

[AnalogSteph]

You know, every time I see a subwoofer with a 3-pin IEC mains inlet (potentially indicating an IEC Class I device), I am wondering why people don't have hum problems more often... Without any special measures being taken inside the sub, those would be almost 100% guaranteed in your setup.

For curiosity's sake, I would advise measuring the resistance between the ground pin on the sub's power inlet and RCA input ground (sleeve). A fairly basic multimeter (20-30$ class) should do just fine, it doesn't have to be a Fluke. Also test the regular low level input in case there's a difference between that and the LFE. If you find what amounts to a direct short (compared to probes shorted together), I am not surprised by your problem. If there's 100 ohms or a full kOhm, things would get a whole lot more interesting...

 

[Snoopy]

Maybe a ifi Gnd Defender could help ?