Stereo feedback
 

My dad is making me ask, though I think I know the answer, or part of the answer. He is having issues with a lot of feedback with his stereo system. Its a off brand Technics receiver hooked up to 2 large tower speakers. He is using an extension cord to connect them (what I think the problem is) and has the computer running to it via 3.5 to RCA. Its a really bad buzz feedback. Any idea what it might be without seeing it or hearing it? I say its the wiring, being as its extension cord. He is a cheap fellow.

PS, it has feedback on all inputs, either TV, VCR/DVD or the computer. Could it maybe just be the receiver itself? Its about 4 or 5 years old.

My pc sound system does the same. I'd like to know the answer as well. I always figured it was a bad ground.

Extension cord should be fine. Sound like either the amp or speaker is wack. If you plug your ipod in as a source does it still buzz?

Hmmm, its both speakers, so maybe its in the receiver itself then.

Let's define terms here. You have a hum, right. Feedback is what you hear when a band has the PA turned up too high.

Disconnect the computer from the receiver and see if the inputs on the receiver work okay. It sounds more like a ground loop than feedback. Is the receiver plugged into the wall plug or are you using some sort of adaptor? The point is if the receiver AC is 3 wire and are you using all 3 wires? Or do you have it plugged in with some pigtail adaptor and not getting the ground or have the AC plug polarity reversed.

short out all three contacts together on the 3.5mm plug with the RCA's plugged into the amp and everything turned on to a volume where you can hear the buzz. If the buzz goes away, it's the laptop or a mediocre RCA-3.5mm adapter.

most likely the source as mine did the same thing back in the day, built a new computer with onboard sound card and no more hum.

edit: never could figure the first one out, tried all kinds of stuff, new power supply, better grounding

It does it on any selected input, even if nothing is being played, with the volume over about 1/3 volume, it can be heard. It also just started one day, nothing was moved or unplugged. I'm thinking its just the shitty brand unit is crapping out.

Does the extension cord run by the computer, or away from it? If it is by it, move it so it isn't and re-try.

Most likely problem, defective RCA cable. The buzz is not "feedback", it's 60 Hz "hum" pickup. Maybe one of the jacks is loose.

Is the computer plugged into the same outlet in the house as the amplifier? If not, try plugging them into the same point.

It ended up being either the cable or the RCA adapter. He messed around with it and narrowed it down. It was after all a cheap thing I picked up at Walmart for like $5. I guess try another brand. Thanks for the help.

I would bet on the RCAs, I've had it on them as well. Going with a better quality cable will help but I could never get it completely out. Best way to get good sound is to go with digital coax or fiber if your PC and receiver support it. Analog cables easily get interference.

Some good cheap cables that may help.

He isn't much of a computer person, so he gets my old computers, and the computer only has on board sound card with standard 3.5 ports. I showed him the wonders of Pandora and now I have to put up with that all the time now. I hate his taste in music.