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SamFisher Unregistered guest | I've recently started getting a buzzing sound through my speakers. I suspected it was because a power wire was close to speaker wires but that doesn't seem to be the case... Any other suggestions??? (I have a Harman-Kardon AVR210[about 4yrs old], Sony DVD, Rogers HD cable box all wired together with optical cables and higher end RGB's) Is this common with this receiver? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3360 Registered: May-04 | Is it a buzzing sound or a humming sound? Hum is 60Hz and generally ground problem issues. Buzz is any frequency above 60Hz and is most often, as you guessed, an issue of EMI leakage between cables or components. Has anything changed in the system recently? |
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SamFisher Unregistered guest | Now that you mention it, it is more af a humming...I've had to shift the unit a couple times and occaisionally change the RGB's in the back of the TV (Sony XBR) I have XBox and PS2 but only 1 input for those two systems(the Sony DVD and HDTV use the other inputs) The humming is pretty consistent through all the video and DVD inputs which makes me think the might be an issue with the receiver or EMI interference. If it's a grounding issue, where would be a good place to start troubleshooting? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3374 Registered: May-04 | You're probably not going to like the answer, but the best way to troubleshoot this would be to disconnect all the interconnects and video cables to see if the noise exists within the unit or is being caused by a faulty cable or connector. With everything unplugged, listen for noise with the unit ONLY connected to the speakers. Add one interconnect at a time and listen for the problem to return. Hopefully this is a bad interconnect that will be easy to trace. |
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New member Username: TedworldPost Number: 1 Registered: Apr-05 | Disconnect your incoming TV cable from the cable box or wherever it first touches anything connected to the rest of your system, (best to just unplug from wall) and see if it still hums. If humming ceases, you need a cable ground loop isolator such as the "CISP" about halfway down this page: http://www.cencom94.com/gpage.html8.html it is $11.98 and good to 2.5GHz, gives lightning protection and is comparable to the $65 Jensen ripoff. |
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SamFisher Unregistered guest | Thanks for the tips guys! I'll give them a shot |
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SamFisher Unregistered guest | Well, no luck yet.....Very frustrating! I've unplugged every single component connected to the amp and there is still noise! Please don't tell me my receivers cooked!? (Harmon-Kardon AVR210) Any last suggestions? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3510 Registered: May-04 | If the receiever still makes a noise with every other component unplugged from it and the wall socket, the unfortunate problem is in the receiver. |
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Bronze Member Username: AudioholicPost Number: 30 Registered: Apr-05 | It sounds like a ground loop. Recently had the same problem. Drove me nuts for a week or so. Finally solved it. Bought a 3 prong to 2 prong adapter and inserted it on the power plug of the offending piece. In my case it was my amp. $.62 fix. J.Vigne is right though. You need to unplug everything from the amp and one by one hook them back up. |
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New member Username: TedworldPost Number: 3 Registered: Apr-05 | that's the worst thing you can do. NEVER lift a power ground lug. If you have hum, use isolation transformers available for about $5 for each stereo input or output you need to eliminate the hum on. The ground lug is there for a reason. Use it or risk electrical shock, component killing surges or discharges or even fire. |
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Bronze Member Username: AudioholicPost Number: 40 Registered: Apr-05 | Ted, the unit is grounded just fine, thank you. It's grounded to the pre-amp, as well as thru the interconnects. I'm not the slightest bit worried. Thanks for your concern though. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3692 Registered: May-04 | Paul - I think Ted is referring to earth ground of the AC circuit. When a surge or lightning strike comes thru the line, there has to be a straight, simple ground path to earth for the voltage to use as an exit route. If the third lug for the ground to the AC outlet is missing, the voltage will use that ground path through your pre amp and interconnects to destroy your system. What you used are called "cheater plugs" by electricians and should be used only on a temporary basis such as diagnosing the problem. This is particularly true if you are using a surge protector, as they rely on the earth ground to dump voltage. |
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New member Username: Uber_klausPDX, OR USofA Post Number: 1 Registered: May-05 | Hey guys, I think some of you are over reacting to the ground lift issue. I own a sound company. The very first lesson I ever learned in this industry was when your p.a. system buzzes, try lifting the ground on one end of your multiple run ac lines and if the problem goes away, you had a ground loop! For all those who claim that lighting bolts are going to jump down and kill your system, I can tell you that in 23 years of doing gigs and club installs (over 3,000 gigs and more installs than anyone in my area), I have never lost any equipment (and I own A LOT of it) due to a stupid ground lift adapter. You have alot more to worry about if you use both sides of your ac panel (each side of 220 coming in) and you ever lose your neutral, THEN you have A LOT to worry about, as you will definitely lose some gear and / or fuses. Not all buzzes are caused by ground loops but most are. I have used three prong to two prong adapters about a million times. If I hadn't, I would have some big-azz buzzes and some really unhappy clients and listeners. If the problem goes away, I say use the damn things. If you're really worried about, then get yourself an excellent isolation transformer which is what I did for all my pre-amp gear because it was offered to me dirt cheap. I use a ONEAC (pronounced ohn-e-ak) transformers and they are specially wound transformers that don't allow spikes to go through or any dirt created from switching power supplies to infiltrate your gear either direction. These are used by large companies that may have huge amounts of computers or electric typewriters that send tons of switching power supply crap back down the ac line and then that affects all the other pieces of equipment. The transformers effectively block all that noise and provide spike free duty. They are about $100 an amp (new). Probably unaffordable on your power amp but easily affordable for your pre-amp stuff. Especially valuable on sensitive satellite boxes. Anyway, I say if your buzz goes away with a adapter use it. Buy some really good power strips at least - not your $10 variety. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 3707 Registered: May-04 | Welcome to the forum, Dana. It's always good to have someone with experience making contributions, especially when the issue is how to resolve a problem. I would not disagree with most of what you said, however, let me add my experience from several decades selling and using consumer and professional audio. Since the issue is raised in the portion of the forum which pertains to Home Audio, I will assume most of the posters will be taking their AC power from an outlet and not having to directly patch into the main panel of their home. None the less, there are worse things that can happen to a system than a power surge. From my experience, living in Dallas, the lightning strikes can be quite devistating; particularly to any equipment which relies heavily on IC's. That would include much more home theater gear than professional audio. Ground lifts are fine for tracing a problem. I do have a problem with ground lifts as a permanent solution to the problem in a home audio system for several reasons. First, a surge protector will drastically downgrade the amount of voltage the unit can safely handle when an earth ground is not present. Why endanger hundreds, if not thousands, of dollars worth of equipment for the cost of a ground lift? Secondly, most home audio is not separately grounded to earth through a three pin AC plug nor is it electrically tied to a common ground through a rack as most pro audio will be. When each piece of gear represents its own ground path, there is the potential for more damage, in my estimation, than when a separate common ground is available. It is often this mixture of two and three pin AC plugs which gives rise to the ground loop problems found in home audio. The issue of a ground lift is actually of minimal importance since most home gear will not have the facility for its use. While lifting the ground on one piece of equipment might be a solution to a problem, making certain everything is at the same ground potential and is supplied with a dedicated earth ground seems to be easy and inexpensive insurance. |
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Silver Member Username: Thx_3417Bournemouth, Dorset United Kingdom Post Number: 368 Registered: May-05 | Sam Fisher Jan has given you lots of top know how's to your audio problem. Most audio cable would fail within a year due to how it's fitted, think about it the cable goes in and is hanging down, this puts little strain on the audio cable, when I was setting up my friends home cinema I made sure the cable was not going to hang down, therefore making it last as long as it should. In the mean time try taking a length of wire and place it one component, the screw, and place the other end on wire one the other audio component, if the buzzing or humming goes away secure the wire to the unit, this may work has I have done it many of times for a quick solution to the problem, but the problem will still be there, and no one likes to fork out hundreds of £ pounds or $ dollars for audio cable when there is an easy approach, it's not a major dubbing studio you know? Good luck and as this is a few months old maybe you haven't seen it lately... |
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Anonymous | Just to let you know if you use a 3 to 2 prong adapter to stop the ground loop, there is a little ring or piece of metal that touches the screw on the faceplate of the outlet that grounds you. The screw for the face plate is meant to go through it threw. So you are still grounded. |