Subwoofer humming with 2 receivers.

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I have two receivers connected to ONE subwoofer, one reciever using sub-out to subwoofer, the other one using a pair of speaker-level wire to subwoofer.

When I turn on the subwoofer, I can hear constant humming sound from the subwoofer, no matter whether the receivers are on or off.

Tried different ways to eliminate the humming sound, eventually I found out if I connect two receivers with electric wire on the rear pannels, it's ok, no humming.

Can you tell me why, and this connection between both receivers is safe enough or not? or have any better way to take? Thanks.
 
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this connection between both receivers is safe enough or not?
or have any better way to take? Thanks.

There's a ground loop between the receivers. It could possibly help if a small 10 Ohm resistor
is added to each channel at the sub-out jacks' grounds on the one receiver, in series with the shield
on the cable going to the sub line in. You could use an adapter with the resistor inside, in series
with the shield, or cut the cable's insulation, cut the shield, and add the resistor in series there.
 
Last edited:
There's a ground loop between the receivers. It could possibly help if a small 10 Ohm resistor
is added to each channel at the sub-out jacks' grounds on the one receiver, in series with the shield
on the cable going to the sub line in. You could use an adapter with the resistor inside, in series
with the shield, or cut the cable's insulation, cut the shield, and add the resistor in series there.

Thanks.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.