Author Topic: Humming Power Supply in subwoofer  (Read 337 times)

Offline jlaubza

Humming Power Supply in subwoofer
« on: January 18, 2020, 11:20:52 PM »
Hi, I'm looking for advice please. I have a large powered subwoofer that has developed a low level but audible power supply hum (not amplifier hum) when operating. I assume it is the mains transformer. What can I do to eliminate this noise?

Thanks in advance.

Offline DavidC

Re: Humming Power Supply in subwoofer
« Reply #1 on: January 21, 2020, 10:18:25 AM »
Open up and check if the power supply have not come loose or the dampening/mounting rubbers have not disintegrated. Also check the type of transformer, a normal E Core transformer may cause a hum/vibration if the rivets gets loose.

Offline jlaubza

Re: Humming Power Supply in subwoofer
« Reply #2 on: January 22, 2020, 10:34:36 PM »
Thanks, I'll check and if I find a solution, I'll post it.

Offline jlaubza

Re: Humming Power Supply in subwoofer
« Reply #3 on: February 14, 2020, 06:40:08 AM »
Humming problem has been solved - turns out not the power supply but a low level hum through the speaker itself.

The cause? A faulty commercially made (TEAC label) coax cable. I was straightening out wiring behind my amp, moved this cable and heard a crackling, scratchy type sound coming out of the subwoofer. I replaced this cable and the hum was gone.

I tested the cable with a multimeter for shorts but it tested clean, no matter how much I twisted and tugged it. Anyway, it has been sent to the recycle bin.

Offline Nico V

Re: Humming Power Supply in subwoofer
« Reply #4 on: February 15, 2020, 02:41:03 PM »
Humming problem has been solved - turns out not the power supply but a low level hum through the speaker itself.

The cause? A faulty commercially made (TEAC label) coax cable. I was straightening out wiring behind my amp, moved this cable and heard a crackling, scratchy type sound coming out of the subwoofer. I replaced this cable and the hum was gone.

I tested the cable with a multimeter for shorts but it tested clean, no matter how much I twisted and tugged it. Anyway, it has been sent to the recycle bin.

Eish...
Holy sacred ground. While I believe you 100%, you just used the word "cable".

Hold on tight - things are gonna get tough from here.

(Hopefully) just kidding! ;-)
It's only funny until somebody gets hurt. Then it's hilarious!!!