Popping from light switches and refrigerator


Help please! My amp just quit working and no one knows why! Two weeks ago the output light on my pre-amp burned out and there was no sound through the system even though the pre-amp tested fine when I sent it in for repair!

I just moved into a patio home (on a concrete slab) three weeks ago. WHEN the stereo actually works, the CD transport misreads and there's a pop out of the speakers when a light switch is flipped, the refrigerator door is opened or the refigerator cycles on.

I've had an electrical engineer look at it and said it was just line noise. I had an electrian come out last Friday and he couldn't find a reason. The three lines coming into the house were all tight and the breakers were all tight.

The light switches and refrigerator are on four different breakers. The electrician suggested running a dedicated line. The electrical engineer said that that wouldn't help since the switching noise seems to be bleeding through four different circuits now.

This happened (before the amp quit working) with both a tube pre-amp and solid state pre-amp. It happened with both a $2500.00 power conditioner and a UPS unit from my computer.

I lifted the ground on the transport, dac and pre-amp and the popping seemed to stop (for that day). The next day the power amp quit working altogether. I don't know what to do!

Chuck
krell_man
I had the same problem in my apartment.
Thought about isolation transformers, power plants,
all the usually audiophile approved ideas.
Then I tried a ac line filter from a company
Sandy Gilman of Audio Den back in Stony Brook recommended.
elect-spec
http://www.elect-spec.com/acprot2.htm#Laboratory
Solved my poping noises.
GTF
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Jea48 - I really like the write up above, and think you may well be correct.
I'm still curious about the condition of the amp though. Chuck moved into the house 3 weeks ago, which makes me think that his audio equipment was moved and unaviodably bounced about at least a minor amount in the process at about the same time. Since the move there have been issues with all several components connected to a common circuit. So while I don't disagree with anything I've seen on this thread, it also seems like there is a chance that an intermittent high current draw from one of the audio components could cause similar issues. L dI/dT can be a bugger.

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It seems to me that your problem is from one of two sources: the refrigerator or the power company. The refigerator motor contacts, brushes or pull-in relay could be arcing, leading to induction or impules noise in the entire house wiring. These voltage spikes can easily fry a CD player's electronics and blow amplifier fuses. Pull the plug on the refigerator and see if the problem goes away with respect to the light switch pops.

Second, the power company has voltage transients carried through to your house from sources such as nearby building motors or on-site generators, transmission wire faults, or your neighbors could be polluting upstream with their motors, computers, etc. This is a bitch to track down. The only thing you can do is complain to neighbors but the utility has a responsibility to attempt a solution if the problem is on their end.

Without knowing anything else, voltage spikes are the most likely culprits for the equipment damage. EM/RFI pollution is the most probable cause of the popping. If it were my house, I would be looking to install an isolation transformer for the entire audio circuit and a TVSS in the main panel.
JEA48 - "Imo he has a bigger problem than that...." . You may be right, or the popping might be coincidental to the other issues, or both. In any case, I don't see any reccomendations above that seem unreasonable and I keep wondering about the first thought from Avguygeorge.

Chuck - Great luck! And if you don't care please let us know how this one plays out, inquiring minds gotsta know.
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Thank you all for your thoughts. After talking to about a million people besides your feedback, I started replacing all of the contractor light switches and outlets in this four year old home. This way I can make sure that there are no loose connections there and I know that these new pieces are of a lot higher quality.

The electrical engineer came over and checked the breaker box thoroughly and the ground rod and connection, things the electrician never bothered to do for the $140.00 service run. I bought a PS Audio Power Plant 500, but can't test it out yet until I get the amp back. I'll try it and then the dedicated circuit to see if I can see what's going on.

Chuck
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The popping noise can just be line noise as the engineer mentioned to you. When you break current flow suddenly this creates an inductive kick (short duration voltage spike) that needs to bleed off somewhere. I've got 10 gauge solid copper dedicated lines from my breaker box to my stereo, a copper water pipe based grounding system that should satisify even the most finatic, and I still hear the pop from one heavily loaded light switch circuit. An alternative might be to have an electrician install surge supressors at your breaker box, this should be pretty cheap.
For what it is worth, we had an intermittent short on a piece of equipment at work that drove us insane for a while. It was on a circuit fed from a large (80 breakers) panel, the short wasn't enough to open a breaker but it would give enough of a spike to blow the most voltage sensitive equipment fed from the panel every now and then.
Anyway, were its my stuff, I'd -
1. Take the measuresments mentioned in the note above & if possible hang a brush recorder or oscilloscope on the line & see if there is anything that comes and goes.
2. Wonder if a short inside the amp is what made your audio life sour, and be anxious to find out what is wrong with it from the shop.
3. Consider a dedicated line for the long term as mentioned above.
4. Once you get data from 1-3 the answer might be obvious.
On the bright side, problems like this are always very simple after you know the answer.
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All your circuts share a COMMON Ground. A computer grade or medical grade circut could be pulled but the simple solution is to isolate a single circut from the 4 that you have and ground that one on a dedicated or non-shared ground. It should cost very little. This will stop the bleed. You will want to make sure that nothing else with motors or pumps are on that line. Most electricians are not aquanted with Audio Grade lines. You will find that you must be specific and might have to use more than one electrician before finding one that understands what you really want. The problem can also happen when the 3 prong outlets are placed in the socket and a ground is established with a metal strip that universally grounds each outlet to a common ground. Make sure that if they wire it is a NEW 3 WIRE Feed wire without a common ground.
I had a similar--(I think)-- situation to that you describe. It turned out to be the common behind the meter where the power comes in from the street.