REL Qbass Hum

Hi
I have an old REL Qbass that has started Humming
I am using the RCA output from the rel in a 7.2 setup

I have connected a wire from the screw on the REL to the chassis on an AV receiver but this made no difference
I then tried to connect a wire to the REL front screw and touch My other subwoofer screw but no difference
I tried to ground My SKY box to the chassis of My AVR but no difference

As a test, I removed the earth from the kettle lead and plugged this into the REL and the hum was there but not loud
Also, something else I found interesting is that when I put the phase switch in the middle there is no hum

I will really appreciate everyone's help, please
Thanks so much
 
Subdubdab:

I'm doing this off or 30 year old memory..... so don't take this as fact without checking. I believe the Q bass used a high level connector protocol, very similar to what they (REL) are doing today.

Signal ground is one of the three leads in the Speakon connector, not necessarily chassis ground on the REL, but easy enough to ring out with a meter.

How are you hooking your Q-Bass to thhe AV receie
 
Subdubdab:

I'm doing this off or 30 year old memory..... so don't take this as fact without checking. I believe the Q bass used a high level connector protocol, very similar to what they (REL) are doing today.

Signal ground is one of the three leads in the Speakon connector, not necessarily chassis ground on the REL, but easy enough to ring out with a meter.

How are you hooking your Q-Bass to thhe AV receie
Thanks for the reply @cyclotronguy
I'm using the low level rca output.
I've grounded the REL to the chassis of the av receiver.
As I mentioned in my original post I tested by removing eart from the kettle lead that goes to the rel. The hum was very quiet but still there if you lean to hear..

One thing I read is that people have had success grounding their ac receiver
I have a denon. Is there a best way to do this please