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Hi, I'm sorry this gets long.For four years I've had an ongoing problem where after a couple of hours of listening my system begins to sound terrible with something not unlike distortion in the high midrange and low tweeter. I've switched all the electronics at least once, invested a lot in a new dedicated a/c line and new circuit-breaker panel, added two different kinds of power filtration, and tried multiple types and architectures of interconnect and speaker wire.
Each time I make a change everything sounds perfect for an hour or two, then pretty bad, then really bad, then terrible again, and powering-down doesn't reset the problem. Only disconnecting and reattaching the various cables does, and then it does even with all the same cables. Indeed fully disconnecting all the cables isn't even always necessary:
When the whole thing first started, four years ago, it manifested as a staticky "whooshing" sound in one channel of my Parasound gear, which would get worse and worse until that one channel had attenuated to 0db, and which could be fixed instantly by walking behind the rig and wiggling the interconnect in question, whereupon there would be a series of static-sounding pops, followed by perfect sound. My confidant from here in the Asylum thinks this is a red herring caused by corrosion on the connectors, but the trouble with that theory is that it still happened when I switched to the Parasound's balanced interconnects and, moreover, didn't recur on anyone's test bench even with the same set of cables and connections. (Incidentally, many of the intervening pieces of equipment have actually ceased to function as a result of whatever is happening, either in whole or in part -- often in the left-front channel only.)
I've had the privilege of getting a lot of one-on-one assistance from a fellow asylum member who has made a number of diagnostically helpful suggestions. To wit, recently I tried setting a multimeter to dc-volts and putting one lead on the outside metal of one of the interconnect ends, and the other lead on the nearest chassis screw of the amplifier, and got a significant (0.4 - 1.1v) voltage, associated with the problem. When I severed and reattached the cables, everything sounded great, and the same reading was zero.
In light of this result I hired someone local to solder drain wires directly to the interconnect ends, with the other ends connected to a ground bar, and a sixth drain wire running to the chassis -- with negligible if any improvement. So I'm ready to try something more aggressive. I've read several discussion threads in which the magic bullet for a similar problem was a two-conductor-with-shield interconnect, where the shield was grounded at one end, but here the consensus seems to break down: Some forum members are reporting success only when the shield is connected to signal ground, by soldering it to the male connector at one end, while others are reporting success ONLY when the shield is connected exclusively to power ground, by leaving it insulated from both male connectors and instead soldered to a drain wire for connection to the third pin of a power outlet.
My system consists at the moment of a panasonic 50" plasma tv, a pioneer DV-79Avi universal disc player, and an Integra DTR 8.4 receiver. In the past I've used separates by Parasound, Bryston, Monarchy, McCormack, Naim, and Linn, integrateds and/or receivers by Arcam, Primare, Rotel, Naim, and Dared, and front ends by Arcam, Naim, Linn, Onkyo, and Harmon/Kardon. Cables have come from Element, Signal, DH-labs, Acoustic Zen, and Blue Jeans. Nothing has made a lick of difference so far, and none of the easily replicable problems I've had with specific boxes have ever repeated themselves on anyone's test bench.
Any reactions you have would be greatly appreciated. (Again, sorry this is so long.)
Edits: 02/26/10 02/26/10Follow Ups:
Hi!
Do you listen at very loud levels ?
Speaker brand/model ?
Have you tried changing the speakers ?
Any visible corrosion (green/blackish copper) in the speaker cables ?
Does any component get unusually hot during the bad sound phase ?
Edits: 03/17/10
Faced with a similar problem, I found a solution by accident. I removed gold completely from my system. (I now use Progold on copper and brass surface.)
You may try removing gold plating from a pair of banana plugs, and see if it helps a bit. Some time is needed for it to settle down.
I just got another correspondence in another forum that said...
1) The build-up of DCV between the rca shells and the chassis can't be drained by soldering a drain wire from the rca shells to the chassis, because that will "just dump all of that DCV back into amplifier common," and, moreover,
2) I can't attach the drain wire to the third pin of a power outlet, either, because that "will tie amplifier common to earth," which will cause significant problems (e.g., blue flames leaping out the back of my equipment after I power it down, which has already happened).
If both of these statements are true, and I've got measurable DCV between the rca shells and the chassis associated with this noise problem, what's my third option for draining it?
Just an update (and a shameless bump, sorry), to report that someone in another forum thinks RF/EMI has little to do with this, and that instead the transformers of my assorted pieces of equipment are being "thrown into oscillation" by something in my system. This would explain why neither the sound problems, nor a wide assortment of ancillary symptoms (e.g., a CD player whose outside chassis gets burn-your-fingers hot to the touch in my house) never manage to repeat themselves on anyone's test bench.
Three new questions for the room, then:
1) Is this explanation consistent with the practical side of how this problem has unfolded (specifically, could it be robust to change-outs of everything including all three types of cables)?
2) Is there a way to diagnose it with my multimeter and, if diagnosed, is there a remedy?
3) Am I safe in assuming that the money I've just spent on two-wire-with-shield interconnects would have been to no benefit whatsoever, in the face of a transformers-in-oscillation diagnosis, or should I proceed with the attachment of drain wires to those IC's when they get here, anyway?
Transformers being "thrown into oscillation" is kind of vague. You can get oscillation wherever you have a gain stage.
I suspect the business with the DC voltage arising is a symptom, not a cause (by the way, when you're measuring that voltage, have you ever switched your meter to AC? I'm curious what you'd see then.)
I reiterate my suggestion to begin with a very basic system: receiver (you did say you're using one in your original post), speakers, and nothing else. If this causes the problem not to surface, then connect the CD (a universal DVD player?) player with two interconnects, nothing else. Plug the power cord of it into the back of the receiver, or, if there's no socket, plug them both into the same power strip. Remove all other connections, including anything connected to the TV (cable is notorious for introducing grounds loops, and although your problem does not resemble a ground loop, it would be better to eliminate any such weirdness from the mix).
Your mention of the CD player getting hot is interesting. Another experiment might be to power that up and turned on while connected to nothing (make sure it's ventilated), to see if it still overheats.
I still suspect power issues somewhere.
Thanks again for continuing to take an interest; the CD-player-with-no- connections experiment is something I should've tried a long time ago.
Meanwhile, as for reconstruction, yes, basic systems of the sort you've described have been tried in the past with the same result, and have been repeated with different configurations of equipment -- but I *am* willing to try again in the interest of clarifying the data a little. (Tried Arcam CD-23 directly into Naim Nait5i, same result; tried Onkyo CD-changer directly into Primare SPA21, same result.)
The difficulty is with what that leaves, which doesn't seem to be strictly possible:
The problem exhibits many of the same characteristics as static electricity, in that it builds up continually and then dissipates all at once, and only under certain circumstances (disconnecting or, in some cases even just wiggling, the interconnects). I've even had some luck recreating the problem, or something like the problem, artificially: when I had zero-feedback monarchy power amps, I could induce 60-hz hum by having a Jensen CI-2RR ground loop isolator installed between the preamp and them, and when I broke the connections to the CI-2RR and re-established them exactly the same way, the hum would be gone completely.
The trouble is that each time I say this to someone who knows what he's talking about -- each time I say, "Now, doggone it, Joe, something pernicious is building up inside the system in just the same way as static electricity, and can only be dissipated by severing the interconnects," that person sooner or later has no choice but to say something not unlike, "that's not possible."
That DC voltage measurement is probably a critical piece to the puzzle.
I just want to nail down exactly what you measured, from what to what. You had the system running, playing music and it was sounding bad. You had an interconnect plugged into an RCA jack of the box and measured between the outer shell of the RCA plug and the chassis. Correct?
At this point what I would do is one by one take each of your components and unplug their power cords and unplug any other wires connected to them (interconnects, speaker cables, antennas everything). Use the ohm meter to measure the resistance between the outer shell of each RCA jack to the chassis and to the ground pin of the power plug (if it has one).
Then put everything back together, play music and wait for the "badness" to happen. When it does use the volt meter (make sure to set to volts not ohms this time) and measure the voltage between all pairs of chassis. Its probably a good idea to pare the system down to as few boxes as you can and hear the problem, fewer possible pairs that way. In addition repeat the test you already did, but do it for all the plugs, on all the components.
Put all that in a nice table and post it here. A diagram of the system showing whats connected to what (including how the power cords are hooked up), and especially which components have two prong and which have three prong plugs would help a lot as well.
It sounds like a lot of work but it really isn't that bad, its just a lot of data. Most of that data is going to be irrelevant but its a lot better to have it all at once rather having to come back several times and say "could you measure this and check that".
It might be grounding issues, but it could also be something seemingly unrelated like the dryer being hooked up wrong!
It really sounds like something is building up a charge somewhere along the line.
John S.
Thanks for writing! I appreciate everyone's help in trying to get this fixed but none more than from those who are prepared to take what I'm describing in good faith.
I agree that a charge seems to be building up somewhere, though several people who are trying in good-faith to help have said that this isn't really "possible," since powering-down and unplugging from the wall doesn't seem to help; only disconnecting the interconnects between the boxes.
In answer to your question, yes, what I've done so far is to set the multimeter to DCV and hold one lead to the outer shell of an RCA interconnect at the amp end, and the other lead to the nearest chassis screw on the amp, and have gotten readings other than zero that get bigger and bigger as the sound gets worse and worse.
I will do as you suggest and report back, but in the meantime I've had some interesting correspondence in other fora on the question of shielding. I've been thinking that an interconnect architecture in which both a positive and negative audio conductor are surrounded by a separate shield would improve things, but there seems to be a lack of consensus about whether the shield should be grounded to signal ground (by connecting it at one end to the shell of the interconnects), to chassis ground (by connecting it to a drain wire and thence to a chassis screw), or directly to power ground (by connecting it to a drain wire and thence to the third pin of a spare power outlet.
The signal ground advocates fear that connecting to power ground will create a ground loop, and the power ground people fear that connecting to signal ground will "merely dump all of that noise back into the transformer," whatever that means. I took a look at a thread in another forum in which a person whose amp chassis was "tied directly to power ground" hooked his drain-wires from the IC shields to a chassis screw, thus "splitting the difference" between the two approaches, in a way.
Would you have any thoughts before I start assembling the data table you've suggested? I have a (relatively cheap) set of two-wire-with-separate-shield interconnects headed my way, should I wait to start building the table until they get here?
rent a gas powered generator, and run the system from it, and see if it still does it -- nice way to eliminate the house wiring completely from the equation for testing
Strip it down to essentials. Disconnect everything except the receiver and speakers (listen to FM with a basic dipole antenna, nothing fancy to confuse the issue).
Does it happen under these conditions?
It's a fascinating problem, but I'm sure glad it's not happening me. Do you have any hair left?
if the ground loop does not work. I would use more than 1 outlet. If theres 1 on the other side of the wall I would test with an extension cord if it plays fine cut a small hole next to it & run the power strip to the home theater. Im lucky I have 3 seperate outlets for my ht.
I thought I would have problems because I like to turn on all the amps for playback.I dont know anything about electricity so I wanted to use as many outlets as possible. I use 4 power strips.
2 amps are on 2 different outlets.the other 2 are on 1 outlet with different power strips. 7 components including the tv will get tuned on at once with no problems. but most of the time only 4 are used. the other stuff is for more speakers amps different sound. any way I hope you fix it.
ps the only problem I had was I use to use a 75lb 150 watt kyocera amp with the other amps & it dimmed the lights so I replaced it with a 100watt amp.
mch dvd-a mch sacd & blu-ray concerts rule.
v.i.
Million miles from home.
Ben's suggestion is not altogether different, and might not be so laughable:
My current amp and front-end are both very affordable. (Dared DV-6C powering a Pioneer DV-79AVI.) If I had two identical copies of at least one of them, with- or without two identical copies of the interconnects, I could politely switch from one set to the other as soon as the signal started to degrade....
you said that it plays fine for 2 hrs. I have about 20 component hooked up in my living room. theres no power conditioners ect.
I use 3 different outlets with cheap power strips. after 2 to 3 hours im bored with it. you had a post a while back stating you sorta fixed it.
plus other post by u say your gear sounds like crap at other peoples houses too. at least u have 2 hrs to enjoy it.
If I had your problem Id turn the amp & player off & use a different one after 2hrs. I can do that I have 4 amps & 9 dvd players.:] seriously I bet your stuff sounds better than mine. you have hi end clean power & source components :> }}
mch dvd-a mch sacd & blu-ray concerts rule.
You're right, Ben, the record of this problem is littered with breathless announcements that I'd fixed whatever was wrong. I've also exascerbated things by periodically getting so discouraged that various offers of help have languished on the vine, perhaps leaving some with the impression that I don't really *want* to get this fixed. So I really don't blame you for being sick of reading about this, believe me. Indeed I was waiting for someone to say something more like, "Um, don't you have other people to pester, or something?"
All of that being said, no, it's not garden-variety listener fatigue, as has been verified by several scientifically repeatable experiments with measurable outcomes. Not least of these is the voltage between the IC connectors and the chassis, corresponding in a straight line with the depredation in the signal. I did one experiment with Jensen CI-2RR ground loop isolators and got an enormous ground-loop hum, then severed and reattached the IC's to either end of the isolators and the hum was completely gone and everything sounded great. Also, I had some non-audiophiles listen double-blind and they heard it too.
The power filtration has been added amid this whole nightmare, and has neither added nor subtracted from the problem. I'm only using it all now because on those occasions after I've severed and reconnected everything, the "good" sound is better.
Your idea is actually not a completely un-workable solution: I could have two moderately priced amps and two front ends and two sets of cables for a lot less than I've spent so far trying to diagnose this; the trouble is that whatever the problem is, it periodically eats things: I've blown the left (or left-front) channel on three different pieces of electronics, and replaced the left tweeter on two different pairs of speakers. Plus there is the concern that continually working the connections on the backs of the equipment will cause their contacts with the internal circuitry to break.
The solution I'd like to try is a drain wire attached to the shield of a set of IC's in which the shield is not also the signal ground, but there seems to be no consensus about whether the shield should be connected just to signal ground (at one end, obviously), or to chassis ground, or to power ground. If the former, I can buy those for $35/pair on Ebay without having to do anything. The middle choice is what someone on that other thread says they did, and worked for them; the third choice seems to be the only one available if the digital front-end has a two-pin IEC socket instead of a three.
how old is the wiring in the house? the panel? does it have an old fuse box feeding the panel? how about the lines coming into the house? nearest transformer?
What's the voltage doing when this happens? is it steady 120 or is it dropping/surging?
I had a similar albeit temporary issue where the power company replaced a blown fuse to the nearest transformer (which was basically in our backyard and feeding the house). However afterwards we had massive power flucuations, mostly leaning towards brownouts then surging back up. Everything turned on or plugged in made horrible humming and whining noises (the stereo was unplugged). Voltage was around 100 to 108.
The power company tested the main branch and traced it back to the transformer whose fuse they had replaced. The transformer was bad. Replacing the transformer only barely helped so they traced it further down the line to another fuse.
Long story short.... the bad fuse further down was causing some weird negative feedback, power suckout and surging to our house.
The fact that you've blown equipment makes me wonder about the power.
My Photos
1. The home entertainment rig is on a dedicated, safety-grounded circuit, leading out to a breaker box that was installed at the same time, about halfway through this four-year ordeal. The rest of the house's wiring, which uses the same box, is c.1949 and only two-pin instead of three (no safety ground). The line feeding the dedicated outlet is romex but the other lines are of the older style that looks and feels like tarred felt around the outside.
2. The voltage at the dedicated outlet will wobble around 121.4 one time I try it, then wobble around 120.7 the next time, then wobble around 121.6 the next time, etc.
3. The nearest tansformer is on the pole directly in front of the house and it has recently been replaced, along with several others in the neighborhood.
4. They've recently tested my line for voltage drops and they were satisfied, which doesn't mean that there wasn't any problem.
Is the TV always connected to the system? That's where I would start disconnecting.
Peace,
Tom E
I've tried it with the TV unplugged from the wall, plugged into a different outlet, etc., but I do need to try some more tests in this regard.
One reason I'm thinking the TV could well have something to do with this is that the Sony DVD-players to which I was always very brand loyal all had a tendency to periodically issue a loud, upper-midrange bang down the audio interconnects from time to time, like the loudest removal of a piece of masking tape from a door lintel in human history, but two of them have never done this since in the houses of close friends, and the third of them was bought with this caveat by someone on audiogon who reported no recurrence.
The frustration that comes with it is that the problem "seems" to pre-date the acquisition of this TV. As I've said elsewhere in this thread, the data is as noisy as the problem, but it does seem to me that I was having all these problems with earlier configurations that didn't include this TV.
One possibility that I haven't completely ruled out is that the hdmi cable could be causing a ground loop -- but even this seems unlikely since I've heard these problems with TV disconnected from AC power.
What do you think about this drain-wire hack that I found on another forum? The person in question took a set of two-conductor-with-shield IC's, with the shields connected to signal ground at one end, and soldered a drain wire to the shield at that end, and connected it to his chassis. The wrinkle is that I wouldn't be able to do it at the digital front end, because my digital front end's IEC socket is only two pin, instead of three.
I meant disconnect the TV from the system, not merely unplug it from the wall outlet.
I think you need to restart with the most basic setup and proceed from there one step at a time, with two channels, one source, one amp, one pair of speakers, one set of IC's and power cords, and NO drain wires, power conditioners, TV's, hdmi's, etc.
Peace,
Tom E
Could you possibly have a TV cable box?
A friend of mine years ago had a problem with his cable switching channels and even turning off by itself when lightning was nearby - a big pain when trying to record some shows. The only thing suspicious was a higher level of voltage coming off the case of the cable box than usual (too long to remember accurately - maybe 3-5 V). Just guessing this might have some effect, I ran a ground wire from a screw on the cable box case to the AC outlet plate screw and the problem was solved. Sorta surprised me, too. I wish your problem could have been that easy; 4 years of PITA.
...unfortunately, no: There's no signal coming in to the TV whatsoever -- no cable, no satellite, not even rabbit ears. I only use the TV for watching movies.
On the other hand, the homeowner before me was a master-craftsman furniture maker who also seems to have thought he was a Bob-Villa-expert at everything else, too, and left a lot of insidiously blind outlet plates cut into the walls of the living room. Could there be a crossed set of wires behind one of them, arcing? And if so, could that cause enough EMI/RFI to explain all of this?
This has be going on for 4 years! I wish I had some insight for you. I am just happy to see that you are still able to write a coherent post after this ordeal. It seems you have been able to keep your sanity(relatively... after all you are HERE)
The ground loop problem that's kept me from listening to my system for the last few months seems trivial by comparison.
I hope a solution presents itself soon.
Julien
"There's someone in my head, but it's not me"
If I remember correctly, you are the person who took possession of my backup pair of Element speaker cables, yes?
No, Sir, that wasn't me. But I'd like to try a set.
I believe my problen is that I installed a dedicated line just for an amp.
I didn't configure it for balanced power as per the request of the person that performed the restoration.
The rest of my system is being feed balanced power from a transformer in the crawl-space under my house.
Between this unusually cold weather and work commitments I haven't crawled under there to rewire the transformer for straight isolation.
This is not a truly justifiable excuse, but it's mine and I'm sticking to it. :~)
I am still shaking my head over the knowledge that your problem had been going on for 4 years and you aren't a babbling idiot as a result. I'd have gone mad long ago. You are a much stronger man the myself.
Julien
"There's someone in my head, but it's not me"
You should hear how I sound when I try to talk about this in person.
Is there anything in your system now that was there when this problem first made itself known?
(Yeah, I'm clutching at straws.)
Thanks for writing! No, everything has been changed at least once.
It is not the interconnects. The RCA's on your amp are likely modular, meaning they are soldered into a circuit board. There is a bad connection somewhere in the RCA connection from plug to the board. When you wiggle the interconnect, it is moving the connection inside your amp.
___
Long Live Dr.Gizmo
This was only one of numerous pieces of equipment to have sonically similar problems.
Unless you have a completely different system that sounds great and everytime you swap components up and down the chain they sound bad, there is no way you can isolate or generalize the problem. Find the first instance of the problem and fix it. Get rid of your power conditioning, get a simple switch strip and start from there.
___
Long Live Dr.Gizmo
Completely different equipment, multiple times over, same problem. It's either radiated emi, rf, ground loop, or some kind of problem with the grounding of the house's wiring. Perhaps mentioning the Parasound equipment threw us off the bread-crumb trail of diagnosing what's wrong, here, and how to fix it, but so far we haven't communicated.
Lots of completely different configurations, all of which sound perfect for anything ranging from an hour to a day, after which time all of which sound terrible in exactly the same way. DC voltages between the male IC connectors and the chassis. Powering-down doesn't fix, severing and re-attaching the cables does. Parasound stuff has been gone for a long, long time now. Not the problem.
Many years ago I was involved with a large and very expensive electronic test machine that failed to work correctly for many months after it was moved to a new area.
Bizarre symptoms: Erratic random behavour - somtimes, lights suddenly coming on and flashing. Computer rebooting. We swapped many modules which seemed to cure it until it happened again the next day!
Cutting a long, long story short, the tech who did the move mixed up neutral and earth (this was in Europe with a US Blck/White/Green equipment wiring to a big (Hubble??) connector.
In short (bad pun!), although Neutral and Earth are connected back at the breaker, all kinds of wrong currents were lifting the chassis level. With 5v logic it doesn't take much ground crap noise to wreak havoc!
Just a thought - get somene to check neutral/earth integrity. You can't do it yuorself.
Neutral/earth integrity on the dedicated AC line has been verified.
On the other hand, the rest of the house's wiring is all of the old two-pin type, and it has been suggested to me that this could cause something to "back up" into the dedicated line, although others have dismissed such talk as gibberish.
I've tried connecting everything straight to the wall, I've tried a power strip, I've tried just using the isolation transformer, and I've tried just using the Felix. No difference.
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