Loud Hum From Sub.

[CRIMSON PEARL]

Just finished the last connection on my system. Connected sub the same way it used to be with my new Yam 2700 sub pre out. The reciever MASTER power ON or OFF HUMMing from sub ONLY when plugged into reciever or anything else. Level on sub doesn't matter. I reversed the cable (and tried another) and the same thing. It happens when the audio cable is plugged into the input OR OUTPUT of sub as long as the other end is also connected to something. Tried UNPLUGGING all power cords exept sub. Still happens when audio cable is connected.

I'm afraid sub was damaged in move.

I did a test. Connected sub to cd changer. Changer has video connection into tv for on screen display. Disconnected video connection to tv NO HUM, connected has hum. Plugged back into reciever STILL hum. Possibly bad video connection (shielding) someware in setup. I don't know.

[Kevin D]

Ground loop. Is the sub on a different outlet then the other items (receiver, tv, etc). Or is anything connected to the system on a different outlet? Does the hum go away when you unplug your cable or sat feed line?

You can get a 3-2 prong power adapter to get rid of the hum untill you find out where the problem is.

Kevin D.

[Chris D]

Yes, I'm almost all done with an upgrade spurt, and have a hum in my sub(s). Will have to do some troubleshooting to try to get rid of it. At least I was able to get rid of the hum I had in the speakers. Now it's only in the subs.

[CRIMSON PEARL]

Ground loop. Is the sub on a different outlet then the other items (receiver, tv, etc). Or is anything connected to the system on a different outlet? Does the hum go away when you unplug your cable or sat feed line?

You can get a 3-2 prong power adapter to get rid of the hum untill you find out where the problem is.

Kevin D.

It does't matter where the sub is plugged in for the hum to happen. Plugged into a Furman power conditioner now.

Update; The coaxal line running INTO the cable box is the cause. I have to call the cable company now. :T

[subynube]

http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=180-075

I had the same problem with the coax. cable causing the hum. I bought this part from PE as above, and it completely fixed the problem.

[joetama]

Good luck with calling the cable company.

I called them and they told me that there isn't a problem with their equipment it must be something wrong with mine. I'm pretty sure that when I unplug my stuff from their cable and look at it on the O-Scope and can CLEARLY see the noise it isn't my equipment. At times there is over a volt of noise coming in, so I grounded the hell out of everything and it seems to be OK. But still, thanks Time Warner. I am about to buy a big grounding rod and some heavy gauge copper wire and make my own ground and run it up the side of the building to my 4th story window.

I also need to find a good Isolation transformer. MCM is out of the one that I have used in the past.

[Chris D]

Interesting product, Subynube. I'll have to keep that in mind in the future.

[CRIMSON PEARL]

The cable guy grounded the line where it comes into the house and replaced the box with one with HDMI outputs. It did nothing. I'm going to buy a grounding adapter at radio shack later and try to ground it near the box.

If that doesn't work I'll remove about an inch of the ground from the coaxel wire which should solve the problem without ordering anything. What are possible negetives of doing this.

[subynube]

Interesting product, Subynube. I'll have to keep that in mind in the future.

Thanks. This product was actually recommended to be used in my instruction manual for my parts express sub plate amp. It was recommended to be used for hum caused by television coax cable. It did work perfectly in my case, but I know of some cases that it did not work in. Well, it is only a $8 part and can't hurt to try.

[CRIMSON PEARL]

I bought a $4 coaxal grounding block from radio shack. Grounded line to sub body. WORKS perfect. Thanks. :T

[subynube]

I bought a $4 coaxal grounding block from radio shack. Grounded line to sub body. WORKS perfect. Thanks. :T

Just curious, do you have a photo or a link to the product you bought. I would like to know if it is anything like the Parts express isolation transformer that I posted about. Thanks, and congrats that it worked! I always love when stuff works easily like that.

[wettou]

Here it is! http://www.radioshack.com/sm-buy-the...i-2104010.html

The only issue is that you are not suppose to do that it can be a dangerous proposition ask any electrician.

[joetama]

The metal tab on those plugs is supposed to go to a ground line.

Don't use a 'cheater' plug unless you are planning on using a secondary ground line which you are going to connect to the plug.