Back to ask again (long! sorry!)

[dogorman]

If you recognize the user-ID, then you know the problem I'm about to describe because I've been yapping about it in these forums, on and off, for *years*. I'm only in here to try again because everything I've done so far to try to fix it has resulted in just more credit-card bills.

The sound is perfect for the first twenty or thirty minutes -- always has been, and I always think I've fixed whatever's wrong -- and then, gradually, the sound becomes reedy and increasingly sibilant in the upper midrange and apparently "over-modulated" right around the midrange-tweeter crossover.

If I shut everything off and reconnect everything, the problem often goes away for another twenty or thirty minutes, but not always.

It can't be a problem with components or speakers because everything in the chain has been repeatedly replaced, and many configurations have been sent off for service and returned with clean bills of health.

I don't think it's RF pollution because I've encountered the problem at a friend's house, and fixed it doing the same thing, over there: reconnected everything and had great sound for... twenty minutes.

I don't think it's a cracked RCA input socket because the problem has spanned several configurations of equipment.

I don't think it's a bad interconnect because the problem has spanned several configurations of cabling.

I don't think I'm delusional because non-audiophile listeners have commented on both the unpleasantness of the sound before reconnection, and the improvement afterward.

At all events, something seems to be "building up" in the signal path, somewhere, and the act of severing all the connections seems to cause whatever that build-up is, to be dissipated.

Lately I've been trying to fix this by... well... *reading* -- about everything from PS-Audio Humbusters to Audience Adept Response power conditioners and back to the XDC power filters by Channel Islands Audio. Trouble is, I'm cleaned-out financially and I just really don't feel like spending any more money before knowing with a bit more certainty that more dollars spent will point me more definitively toward getting to the bottom of this. Are there professionals who can help to diagnose the problem, and who are then also knowledgeable enough about the industry to recommend the proper fix?

Current system configuration: (many, many others have been tried!)

McCormack MAP-1 and DNA-HT5, connected directly to dedicated AC circuit via Signal Cable power cords

Arcam FMJ-CD23 connected directly to nearby, undedicated AC circuit, via signal cable digital power cord

Sony BDP-S550 blu-ray player and Panasonic TX50 plasma TV, connected to APC H-15 power supply, which is in turn connected to the undedicated AC circuit via Harmony power cord

Salk Songtower QWT speakers, front L and R, Linn Trikan center channel, Totem Mite-T rear L and R.

signal cable interconnects, element cable cross-connected speaker cables.

Thanks again, everybody.

Dave O'Gorman
Gainesville, Florida

[E-Stat]

I always think I've fixed whatever's wrong -- and then, gradually, the sound becomes reedy and increasingly sibilant in the upper midrange and apparently "over-modulated" right around the midrange-tweeter crossover...I don't think it's RF pollution because I've encountered the problem at a friend's house, and fixed it doing the same thing, over there: reconnected everything and had great sound for... twenty minutes.
Good question, but "reconnecting everything" is utterly incapable of addressing RFI issues. The grunge that virtually every device with a switching power supply (much less those that directly radiate RF energy) spews back to the AC line (CD/DVD players, DACs, cable boxes, routers, access points, TiVOs, microwave ovens, computerized washers/dryers, TVs, wireless telephones, burglar alarms, etc.) must be actively trapped in some fashion or another.

That's where the world of power conditioners and aftermarket power cords come into play. I use both strategies in my systems. High current devices like amplifiers usually suffer in dynamic range and punch with most conditioners. There are exceptions, but they come at a premium. I have a reviewer friend who uses a $4000 Nordost Thor along with eight $2000 Nordost Valhalla power cords. A modest $20k solution. At the very least, I would suggest trying a $100 conditioner on all sources which are not current hogs. I use a variety of power cords on my amplifiers ranging from relatively inexpensive Belden based shielded flavors ($70) to throw-the-book-at-the-problem Harmonic Tech Magic Magics ($900) in my main audio system. Untrapped RFI always imparts layers of bright and edgy grunge to the signal. How much? Unfortunately that is system and environment dependent.

In a perfect world, we would drive our systems using separate AC feeds for digital and analog sources having infinite noise rejection using balanced connections. Unfortunately, the real world is quite different.

rw

[Kevio]

Have you considered the possibility that it may have something to do with your ears? 20 minutes is approximately the right time frame for threshold shift.

[dogorman]

Could be ears, sure -- anything's possible at this point -- but the fact that non-audiophile friends are hearing the same things, both the problem and the fix, and the fact that the "reset" period is so short, would *seem* to rule this out. One follow-up question: Are there pro's out there whose expertise straddles all of that electrical, DC-saturation, RF-pollution b*ll****, *and* appreciation for high-end audio?

[dogorman]

I should tell everybody one more thing.

Sorry this is coming out in dribs and drabs, but I have a hunch that this might be an important detail: I started shoveling money at my stereo in the first place because an old configuration of gear and speakers developed this *bizarre* characteristic that several different techies were unable to recreate on their own benches: After extended listening, the left channel would develop a "whooshy" kind of noise, almost like the sound your ear makes when it has water in it, and would attenuate in volume, eventually to zero.

If I went to the back of the stack and wiggled the left-channel IC between the pre- and power amps, I'd hear a series of loud pops in that channel, and then everything would work just fine again, for awhile. As I say, it was for this reason that I started swapping-out gear in the first place, but what the ancient problem and the current one seem to have in common is a tendency for "build-up" to be dissipated by mechanical processes at the back of the stack.

Does this shed any new light?

[Kevio]

Does the original problem you describe occur at all listening levels?

[Mr Peabody]

The fact that you heard a pop and then things were better for a while leads me to believe it may be a static electricity issue of some kind. The pop would be the discharge and since the energy had been discharged the problem went away for a while, the time it took to build the energy back up again. I wonder why just the left channel. Are you in a dry climate? If so, you might try a humidifier in the room to see if it has any effect. The electricity could be coming from other sources but I know if a room is dry the static is much worse. Static and capacitance are the only thing I can think of that take a time to build and would discharge upon touch or disconnecting.

PS Audio carry some outlet products that isolate digital and analog sources. They even have some outlets that don't limit current for power amps.

I just remembered and looked up and sure enough you are in FL so maybe you aren't in a dry climate but it still sounds like static.

You have a nice system hope you can solve the mystery.

[E-Stat]

... RF-pollution b*ll****
Not a pro, but try this: take an AM radio, tune it off station and run it near various components. Tell us if you hear any difference when it is near your CDP.

rw

[E-Stat]

The fact that you heard a pop and then things were better for a while leads me to believe it may be a static electricity issue of some kind.
Or a loose connection inside one of the components.

rw

[hermanv]

I am an EE and the problem you describe does appear to defy all conventional wisdom. My first guess was listener fatigue, pretty well ruled out by the short "reset" period and the fact that most non audiophiles don't really hear listener fatigue or at least don't know they are hearing it.

A couple of questions and a guess.
1. Is it especially hot where your equipment sits? It's not in an enclosed space I hope.
2. Does this happen with headphones? (Borrow a set if you don't own any)

The guess is poor grounding, a DC offset builds up on your AC receptacle, dissipated quickly when power is removed. This isn't a good guess, I think it's unlikely. Do you use one of those power distribution strips with the built in surge suppressor? If so, has it also been replaced? Every cable, connector and power cord replaced during the hunt?

On my first job out of school the engineer assigned to "mentor" me taught me something that has served me well all these years. "It's not what you don't know that gets you in trouble, it's something you do know that isn't so." Please, re-read your post, make a mental check list of all the facts and confirm that each one is still true with the current set-up.

[Kevio]

I'm not ready to rule out listener fatigue without first suggesting a couple experiments: 1/ play it at lower level. 2/ play it a normal level but stay out of the room for the first 20 minutes.

[Rich-n-Texas]

The guess is poor grounding, a DC offset builds up on your AC receptacle, dissipated quickly when power is removed. This isn't a good guess, I think it's unlikely. Do you use one of those power distribution strips with the built in surge suppressor? If so, has it also been replaced? Every cable, connector and power cord replaced during the hunt?
I'm not going to re-read his post again, but remember, he's changed houses, so what are the chances there's a ground issue in both houses. It's possible, but unlikely to manifest itself the same way.


On my first job out of school the engineer assigned to "mentor" me taught me something that has served me well all these years. "It's not what you don't know that gets you in trouble, it's something you do know that isn't so." Please, re-read your post, make a mental check list of all the facts and confirm that each one is still true with the current set-up.
My sentiments exactly.

Lately I've been trying to fix this by... well... *reading* -- about everything from PS-Audio Humbusters to Audience Adept Response power conditioners and back to the XDC power filters by Channel Islands Audio. Trouble is, I'm cleaned-out financially and I just really don't feel like spending any more money before knowing with a bit more certainty that more dollars spent will point me more definitively toward getting to the bottom of this. Are there professionals who can help to diagnose the problem, and who are then also knowledgeable enough about the industry to recommend the proper fix?
I'm sure there are, and I'd suggest you look around for a Home Theater Installer in your area and present him with the same facts you're presenting us. You'll either get this: :out: or you'll see giant $$ in his eyes.

[Luvin Da Blues]

I am an EE and the problem you describe does appear to defy all conventional wisdom.

I've spent over 20 years as an electrician and have given this some thought. I still can make out what the cause could be. My first thought was static but with grounded connections the static would drain off.

This maybe silly but, could you post some pics of your rig and cabling?

[dogorman]

Thanks to all for the helpful suggestions and thoughts! One of the things that warms my heart about all of this is how delicately everyone is handling the possibility that this could be going on inside my ears, or even the rest of the way inside my head. I don't think that it is, but I appreciate how much trouble everyone is taking, not to just call me nuts and leave it at that. Pics will follow when I'm back home, though that will take a few hours.

The rig has been, at various times, out in the wide open of the room, and stored in a horizontal object from which the back has been completely removed and the doors are left open when the rig is running. No two pieces are stacked. Leaving the room and coming back hasn't resulted in an alleviation of the problem, and low listening levels only attenuate the issue to the extent that they attenuate the sound, proportionately.

One thing that seems to be true that I'm not altogether sure is true, is that when the problem is happening there seems to be a different sonic signature to the low-level hum that I can always hear emanating from the speakers. When the problem is happening, the hum seems to have a fuzzy, almost rapid-clicking quality that doesn't seem to be there when the problem isn't happening. The amplifier makes a consistent hum, both down the speaker wires and through its own front panel, and the preamp makes a very loud bang if accidentally disconnected from AC-mains while the amp is on, and the cd-player transformer runs extremely, nay disturbingly hot to the touch, even after short listening sessions -- all of which could be indicative of gear that's having trouble dealing with its power.

Of all the reasons that I don't think this is an "all-in-my-head" problem, the facts that non-audiophiles have heard the difference, and that the earlier trouble with the old Parasound stuff was not repeatable on any of *three* test benches, suggest to me that what's going on is something specific not so much to my head as to my house.

Only one power conditioner has ever been used, but it's been both used and *not* used, with no noticeable difference. One thing that hasn't been tried yet is an isolation transformer. The problem has not been tested using headphones.

As for ground, it's been suggested by another forum member elsewhere that I might not have a sufficient earth ground for my entire house wiring system, or massive amounts of DC offset, and that these root causes could at least explain why so many different problems seem to be cropping up in so many different configurations of gear: whatever the problem from moment to moment, the system is unable to dissipate it down the safety ground the way it otherwise would, and hence is dealing with it by acting-up. This other person suggested that the hum from the amp, the banging sound from the preamp, and the hot transformer for the cd-player, could all be different ways of coping with an inability to dissipate fault energy down the safety ground.

The recurrence of the problem at the friend's house seems explicable for one of two reasons or possibly both: (a) If the root-cause had already compromised one or more pieces of equipment, (b) if the root-cause is something generic to the entire local grid, such as massive DC-offset.

Incidentally, my friend does have a stubborn problem with his rig, too, and it dissipates every time he disconnects and reconnects his own stack. His LP's get reedy and unpleasant to listen to, until he does exactly the same thing.

[hermanv]

...edit....
One thing that seems to be true that I'm not altogether sure is true, is that when the problem is happening there seems to be a different sonic signature to the low-level hum that I can always hear emanating from the speakers. When the problem is happening, the hum seems to have a fuzzy, almost rapid-clicking quality that doesn't seem to be there when the problem isn't happening. The amplifier makes a consistent hum, both down the speaker wires and through its own front panel, and the preamp makes a very loud bang if accidentally disconnected from AC-mains while the amp is on, and the cd-player transformer runs extremely, nay disturbingly hot to the touch, even after short listening sessions -- all of which could be indicative of gear that's having trouble dealing with its power.

Of all the reasons that I don't think this is an "all-in-my-head" problem, the facts that non-audiophiles have heard the difference, and that the earlier trouble with the old Parasound stuff was not repeatable on any of *three* test benches, suggest to me that what's going on is something specific not so much to my head as to my house.

Only one power conditioner has ever been used, but it's been both used and *not* used, with no noticeable difference. One thing that hasn't been tried yet is an isolation transformer. The problem has not been tested using headphones.

As for ground, it's been suggested by another forum member elsewhere that I might not have a sufficient earth ground for my entire house wiring system, or massive amounts of DC offset, and that these root causes could at least explain why so many different problems seem to be cropping up in so many different configurations of gear: whatever the problem from moment to moment, the system is unable to dissipate it down the safety ground the way it otherwise would, and hence is dealing with it by acting-up. This other person suggested that the hum from the amp, the banging sound from the preamp, and the hot transformer for the cd-player, could all be different ways of coping with an inability to dissipate fault energy down the safety ground.
...edit...

Low level hum? No decent audiophile set-up will have any hum you can hear at least not through the speakers. I have heard mechanical hum from the power transformers, difficult to localize, but not an electrical signal to the speakers. This is a good place to start.

1. Remove interconnects from power amp, short the power amp inputs if that's required. If there is still hum, let's talk.
2. If hum is gone re-connect power amp but remove all inputs from the preamp, listen again.
3. Work your way up the chain, it's a pain but be very systematic and religious to do this carefully.
4. Don't forget the head phone test.

Does any equipment have a two prong power plug (i.e. no ground pin) if so try reversing the plug in the outlet. There is usually one combination for multiple boxes that will be hum free.

[Mr Peabody]

If it's a problem with the house power shouldn't it some how effect other things plugged in and just not audio equipment, TV, computer? Has the system ever been in another room just to see if the same problem? Maybe it's just one leg off the power box.

Nice enough gear I would doubt listener fatigue.

I think I'd be taken some of these places up on the 30 day return and trying some power products.

[dogorman]

Will reply to most recent queries later today -- thanks again, everybody, and don't forget about me in the meantime. :-)

[Rich-n-Texas]

What does the contest winner get?

[dogorman]

Hah! The contest winner (and anyone else who's interested) gets an all-expenses paid visit to Gainesville, Florida, to help me listen to this thing and figure it out. How's that? Hey, it'd be cheaper than swapping-out power amps again.

Seriously: Will try the assorted tests suggested here and in other forums, some of them as soon as this coming weekend.

But the more I think back on all the trouble I've seen with this, the more it seems to me that the otherwise scientifically inexplicable chain of unrelated problems with different electronics, none of them repeatable on anyone's test-bench, point to some as-yet unidentified root cause, perhaps having to do with power, such as insufficient earth ground or excessive dc-offset, or something.

Mr. Peabody, would you say an isolation transformer? A PS-audio hum-buster? Or something halfway in-between, in terms of price? (Obviously the electrician's visit isn't mutually-exclusive.)

[Feanor]

Hah! The contest winner (and anyone else who's interested) gets an all-expenses paid visit to Gainesville, Florida, to help me listen to this thing and figure it out. How's that? Hey, it'd be cheaper than swapping-out power amps again.

Seriously: Will try the assorted tests suggested here and in other forums, some of them as soon as this coming weekend.
...

Mr. Peabody, would you say an isolation transformer? A PS-audio hum-buster? Or something halfway in-between, in terms of price? (Obviously the electrician's visit isn't mutually-exclusive.)
Dog / Man,

Frankly I've never heard of a case exactly like yours. If it isn't related to grounds or intermittent contacts, then maybe it's a bad capacitor in some component. If you get a hum through the speakers is certainly sounds like a bad ground somewhere: have you tried "lifting" the ground on the amp? Might solve that problem at least.

As for isolation transformers, I have used a Tripp Lite IS1000 (http://www.tripplite.com/EN/products/model.cfm?txtSeriesID=324&EID=13700&txtModelID=228) with some success; (it's available for much less than the $400 MSRP).

[Auricauricle]

Like you, RF hum is a bane that has not infrequently raised its ugly head and made my listening experience a real chore at times. Your description of bangs and snaps is familiar, and I have managed to quell most of it by ensuring that the interconnect cables are intact and that power cords are as far away from them as possible. I read that your cabinet is clear in the back: T trust that your cables are allowed to run free and clear--were I so lucky! Oh, and one other thing: Maybe you know better, but some of us fools still needed to learn the hard way, but turn the volume down or turn the components off when you make the adjustments. It could save your components or your speakers or maybe a finger or two!

[Luvin Da Blues]

...........some of us fools still needed to learn the hard way, but turn the volume down or turn the components off when you make the adjustments. It could save your components or your speakers or maybe a finger or two!

Whats ya break now Aa? :nono:

[Rich-n-Texas]

Yeah The Dude, tell us. :lol:

[Auricauricle]

I ain't sayin' nuttin'! Goldernit, where the frankenheimer did my pinkie go?!

[Mr Peabody]

Maybe start with something that covers a wide range like the Quentessence or the 4 outlets version. www.amusicdirect.com has a 30 return. Or, you could email PS Audio with your problem to see what they recommend. You might want to watch out though if your reply is buy the top of the line piece :)

[dogorman]

I've just finished uploading eight images to a thumbnail gallery on a hosting site called imageshack, and will post the link to the thumbnail gallery here (http://img21.imageshack.us/gal.php?g=electrics002.jpg). The thumbnails are arranged in two rows of four.

Top row (L to R) :

1) My rig, in its latent state in a rack with no rear panel and front doors open

2) Points of conduit entry to the attic above the breaker (note the small white-painted copper tube, emanating from the wall, just below the elbow of the water pipe visible at right (more about this, below)

3) Electrician-friend's temporary solution to dedicated AC-line. He had two outlet boxes of two outlets each on his truck, so he overlapped the plates a little (background). Undedicated AC line is in foreground. At the moment the CDP, Amp, and Preamp are connected to the dedicated line, and the power supply (which manages the TV and BDP) is connected to the undedicated line

4) Sample of the "controlled chaos" at the back of the stack, including painstaking attempts to ensure that power cords, IC's, and speaker cables only cross at right angles. (Power wraps have no noticeable effect on problem, f-y-i).

Bottom row, (L to R) :

5) Inside breaker-box, made by "Square-D," c.1949. The un-dedicated line serving the home entertainment rig is bottom-left, single breaker

6) Close-up of break in that thin copper tube that emanates from the wall in picture 2, near that elbowed water pipe. I cut this thing with my hedge trimmer shortly after moving in to the house, and it is affixed to an external water spigot in such a way as to suggest that it's a grounding mechanism for something

7) Close-up of the thin copper tube's connection to the spigot, directly below the break -- is this a picture of some sort of grounding mechanism? Should I perhaps have avoided grabbing both severed ends of the thin copper tube, to take this picture? (Nothing happened, by the way)

8) Close-up of the outside breaker panel -- dedicated line is top-right, and it's a split breaker because electrician-friend didn't have a joint breaker on his truck (plans to replace).

[Luvin Da Blues]

One glaring thing I noticed was your ground connection (pic009). This should be redone after scrapping the paint off the pipe 'till ya get to shiny metal and reattach.

Do you have a ground rod also, if you do check that also. I suspect that you have an unbalanced grounding path.

Cheers,

LDB

[hermanv]

I looked at your pictures and my opinion is that your power amp has insufficient ventilation. After the sound deteriorates place your hand on the amp chassis if you cant press your hand against the chassis for 15 seconds or more, it's probably too hot (most people can tolerate 55 deg. C).

I'm not saying this is your problem, but too hot is bad news and certainly could be the problem. Also I'm unsure about the wisdom of putting the pre-amp on top of he power amp (excess heat again).

[Luvin Da Blues]

Just another thought. :idea:

Does your friend live in the same neighborhood? If so maybe you have real bad power in the area. Try phoning the power company and see if they could audit the lines for noise etc.

[twc644]

Hi Dave,
I'm gonna take a shot at this and try to offer some assistance.Dont know if your handy with a soldering iron and multimeter .If so,I'd first focus on the one pair of speakers.
Check for cold solder joints and the resistors and capacitors in the crossover network.You could have a resistor drifting way out of spec or an electrolytic capacitor reaching the end of it's life--once either gets charged up it builds up too much heat possibly causing the problem as one of those items may be prematurely failing.

This info also applies to the amp. It could be something as simple as a cold or broken solder joint somewhere/anywhere in the circuit. This is something easily overlooked and yes sometimes by technicians as they are human and make mistakes.

I've done this myself before when I'm modifying or partially restoring a piece of equipment not paying attention to my soldering skills only to find a poor solder joint caused by my hands 2 days later and being extremely frustrated at myself....the result was one leg of a cap not allowing it to charge properly due to the solder joint compromised or the actual pad on the circuit board damaged.I'd touch up everyone of them and that certin channel finally worked like a charm after I found my mistake.

The hypothetical solder joint could be further down the circuit for a certain rca jack or speaker jack on the back of your amp for one of the two channels ????

One thing to do is open the equipment..another words take the top off and visually inspect the components with a flashlight to see if a capacitor is bulging or has leaked the internal electrolytic fluid..if not with the naked eye then look for any resistors/transistors where the body is discolored from overheating,. Last but not least....look for any burnt areas on the circuit board.

Could be the volume or balance control has some oxidation on the internal wipers.....you shoot some "De-Oxit" in the body of the potentiometer and liberally turn it back and forth 30-50 times to let the chemical hopefully clean the wipers inside. Lots of humidty in your home from the outside heat entering the room over time can cause this or having gas heat where it dries out your sinuses also affecting your equipment especially the volume control...it's a possibility okay.

I know you said in your post the equipment has been given a clean bill of health but something is definitely causing this and I doubt it's your imagination.No,I'm not trying to contradict anyones past comments by any means.To me, this sounds like a hardware and/or passive component problem and not psychological .I hope this info might help you out as thats some very nice equipment you own.Good luck !