[weimar97]

My mom has an Onkyo receiver and a Polk surround system (4 surrounds, center channel and powered sub). She also has a 36" Vega and DirecTV (with cable for local channels). Their house was recently completed, and the surrounds have their own outlets for the signal wires. The powered sub does as well.


There is a pretty bothersome hum (or buzz) sound emanating from the sub, whether the receiver is on or not. The "Auto On/Off" feature does not seem to be working, either.


I've tried a number of fixes, but to no avail. Mom even had the electrician come and re-wire a new RCA wire to the plug in the wall b/c I felt that maybe there was a break in the existing line. This didn't fix the problem. It has gotten to the point where she wants to just give it to me. Which, of course is fine by me, but I feel guilty. I had brough it home with me to try it out on my system to see if it hums here (it didn't-BTW).


I was thinking that maybe it is the receiver, but that shouldn't be the case b/c it's a pretty good Onkyo. (for all I know......) I KNOW that someone's had this problem before; and has found a fix for it. Can anyone advise what to do to remedy this?


Thanks in advance.............


Nice forum here BTW.

 

[Mike Matheson]

Welcome to the forum, weimar97.


One quick thought--you could set the sub up by her receiver and then use one of your interconnects to run from her receiver to the sub. Should let you know pretty quick if it's the wiring or something else.


You might also try using a cheater plug on the power cord for the sub (could be a grounding problem). BTW--the cheater plug isn't a good long-term solution.

 

[HighEndWire]

I would stay away from the cheater plug. It could be a serious safety problem. You could check to see if the removing a particular component (or cable box) solves the issue. In some instances you could be polarity if you have a component that does not have a polarized plug. You could also check for a bad patch cord (again, component by component). You could try the Mondial M.A.G.I.C splitter. Audior Advisor sells it, www.audioadvisor.com. I think it is around $150 though. My gut feeling is it is the cable box. If if is, you could try calling the cable co. and see if they can help or change the box.

 

[weimar97]

well.....to my knowledge, I don't think that there is a cable box other than the DirecTV box. They just subscribed for the minimum cable service so that they can get local channels (DirecTV doesn't offer local programming in her area). So that eliminates the cable box..........


I know Mom is not going to go for removing a particular component at a time. I would gladly do it since I love doing this kinda stuff, but she lives in SC while I live in IN. Besides, all she has in the cabinet is the receiver, a CD Changer, the DirecTV receiver and a VCR. All of these are connected to the receiver inputs though. I wonder if I could convince her to try disconnecting each one at a time to see if the hum goes "Bye-Bye".


I did a little search after I left this thread and read about the "cheater plug" and another remedy in which you connect a ground wire to the wall outlet and a screw within the metal chassis of the receiver. I still don't understand how the "cheater plug" could be dangerous, but then again, I'm a rookie at this stuff.


I did use a short length of cable and tested the sub right next to the receiver when I was troubleshooting it initially. But unfortunately, I can't remember if it hummed or not. I'm thinking it didn't, which would be why I came to the conclusion that the RCA wire in the wall needed to be replaced.


BTW - Thanks for the welcome!

 

[Blade007]

Yeah, it's probably your television (cable TV) causing the problems, try this....


1) Go to radio shack and buy two 300 to 75 ohm television transformers.

2) Tie the 300 ohm ends together (the two spade looking things).

3) Insert that assembly into your cable TV feed INTO your television.



VOILA, hum goes away....right?


Congrats, you've made a cheap and easy 1:1 Isolation transformer, breaking the ground loop caused by your cable television company. THANKS CABLE GUY...

 

[HighEndWire]

The ground is there to prevent an electrical shock. Removing it with a cheater plug poses a safety problem. The above post is correct, see this site for more info: http://smr-home-theatre.org/Ground-Loops/

 

[mbpg]

Actually, if it is a ground loop, and it sure sounds like one, the isolators won't work -- they are for ground cable systems but don't work for satellite. A dish needs to be properly ground, period. Try disconnecting the dish receiver to see if the hum disappears. If so, you at least know the source of the problem.


Regards, Michael

 

[Blade007]

He said his system had Cable television attatched to it.

 

[chief]

I RUN IN TO THE SAME PROBLEM AT MY FRIENDS HOUSE ...I CAN SAY THAT YOUR PROBLEM CAN BE TRACE TO YOUR DISH......TRY TO PICK UP THE GROUND FROM THE ELECTRICAL METER BOX .......IF IS TO FAR TRY A DIFFERENT COLD WATER PIPE