Subwoofer has hum. Toss it?

[Muse]

In January 2003 I bought a DLS 100 watt subwoofer from Parts Express, paid about $131 shipped. It's been little used, it usually isn't plugged in. But last couple times I plugged it in, it hummed pretty noticeably even when not driven. Of course, it remains unplugged now, since it's in my computer room (doubles as home theater, office).

Do I have to get a new subwoofer, or is it possible I can get the hum out of this one?

Normally, I watch my DVDs using earbuds. No acoustics issues, I hear dialog better, don't disturb my neighbors, but certain movies deserve the full 5.1 treatment. And that's not the same without a house shaking subwoofer. :awe: Also, of course, if I have a guest, the 5.1 is the way to go.

 

[YOyoYOhowsDAjello]

Does it hum when there is no signal cable attached to it?

 

[krotchy]

Does it hum when there is no signal cable attached to it?

Yeah, a humming is usually a sign of a ground loop between the power and the signal cable. If it is floating the hum could also be from an unterminated input.

 

[vi edit]

$.99 cheater plug from wally world. Give that a shot.

 

[kalrith]

On a side note, I have a question for a friend of mine. He bought a new Velodyne sub (not sure what model), and it works fine with everything except his computer. When he connects his computer (via stereo to RCA, I think) to his receiver, his sub hums constantly even when he's not sending any sound to it. Does anyone have thoughts on this problem? Sorry I don't have more or better info on it, but I'm just going off of memory on this one and don't have access to the system.

Edit: Oops, I deleted my first question once I realized yoyo asked the same thing.

 

[Muse]

$.99 cheater plug from wally world. Give that a shot.

What exactly is that? It so happens I'll be driving right past a few Wallys today (rarely happens). What exacltly am I looking for there?

 

[kalrith]

What exactly is that? It so happens I'll be driving right past a few Wallys today (rarely happens). What exacltly am I looking for there?

I think he's referring to one of these.

 

[vi edit]

I think he's referring to one of these.

Yup. That's it. It's pretty common for plate amps to pick up a ground loop hum. The cheater plugs can often fix it.

 

[Muse]

Yup. That's it. It's pretty common for plate amps to pick up a ground loop hum. The cheater plugs can often fix it.

Ground lift? Yes, I have several. I usually use them to allow me to plug in a grounded plug to an ungrounded outlet, happens to be often. For instance, my wet-dry vacuum.

I turned on the subwoofer a few minutes ago and hear no hum. Not sure what's up with that, last times I turned it on the hum was pretty loud. I'll have to run some tests...

 

[vi edit]

Ground lift? Yes, I have several. I usually use them to allow me to plug in a grounded plug to an ungrounded outlet, happens to be often. For instance, my wet-dry vacuum.

I turned on the subwoofer a few minutes ago and hear no hum. Not sure what's up with that, last times I turned it on the hum was pretty loud. I'll have to run some tests...

I think it depends on what else is running on that circuit. Fans, radios, vaccuums, ect being run at the same time on that same cicuit can provide noise on it.

 

[Tiamat]

sometimes is a combination of items on the circuit that could generate the ground loop. Many times its the cable box's fault. Sometimes, a refrigerator when the compressor is going.