Back to ask again (long! sorry!)

dogorman · « **Reply #40 on:** 18 Mar 2009, 08:46 pm »

It's been suggested in another forum that one of the reasons this whole thing seems so inexplicable is that root-causes are being unwittingly bundled with their immediate effects, by yours truly.

If, the argument goes, the house had a bad earth ground, or lots of DC-offset, or both, then these things could be compromising the performance of different pieces of equipment in different ways, and that this would explain why certain things about all of this seem so scientifically unlikely. By this logic could DC-offset be attributable (if only indirectly) to a problem that takes time to crop up.

The rig is currently stored in a cabinet but the cabinet has no back, the doors are left open on the front, no two pieces are stacked, and there is no discernible difference in depth or frequency of trouble from back when everything was hanging out in clear air -- which is not to say that the cabinet can't possibly be a contributing factor, it just doesn't seem as likely to me. Incidentally, when the minimal configuration was tested over at my friend's house, everything was in clear air.

Could the fact that my earlier Parasound separates had such an enormous problem, and that three separate service departments (two local, plus the manufacturer) failed to recreate it on their benches, further point to power/grounding issues at the house?

jules · « **Reply #41 on:** 19 Mar 2009, 12:48 am »

A couple of questions about the heat issue ...

* can you smell anything?

* do the power cords get warm?

There's been a number of good suggestions made here and you still need to follow them up if only to eliminate them. The 20min factor seems to indicate heating up of a a substantially sized object. Could you do the test I suggested some time back and see if the transformers are overheating? If you are unsure of how to go about this please ask as there is a risk when checking electrical equipment even after you've turned the power off.

Jules

ps transformers can get hot to the point that their insulation breaks down. This can be cumulative and it can also be dangerous [in some types of transformer] if you get mains leakage into other parts of your system.

pps don't worry about the magnetic field from the furnace. The strength of a magnetic field drops away very quickly with distance. Don't worry about the heat from the furnace unless the paint is blistering on your speakers

.

richidoo · « **Reply #42 on:** 19 Mar 2009, 01:41 am »

Good points there about caps and the noises Scotty.

It is more likely that offset is causing the otherwise silent like a rock McCormack amp to buzz and hum and oveheat than anything else even if DC rails are still balanced +/-. Especially while all the components are acting strangely in a similar way.

Indie, I hope you will report back when utility has tested the AC.
Rich

dogorman · « **Reply #43 on:** 19 Mar 2009, 02:40 pm »

Will reply to most recent queries later today; thanks again, everybody, and don't forget about me in the meantime!

dogorman · « **Reply #44 on:** 19 Mar 2009, 05:18 pm »

The tests suggested here will give me a big step (perhaps as early as this weekend) in the direction of finally slaying this dragon; thanks to all. In the meantime, I've had this opportunity to go over, in my own mind, the litany of problems I've had with different configurations and types of electronics, and it seems increasingly likely to me that the only plausible explanation for all of that bad luck (that could never be repeated on anyone's bench) is something to do with the power.

mjosef · « **Reply #45 on:** 19 Mar 2009, 08:24 pm »

Yeah, two constants, the power line and yourself.
This has to be the weirdest situation I ever read of.
Good luck anyway, will be interesting to read the solution.

jules · « **Reply #46 on:** 19 Mar 2009, 09:09 pm »

OK, a couple more thoughts:

You say it takes 20 min to develop the prob. and it's "fixed" by turning off and then on again. Does it take another 20min to recur? If not, what's the interval?

Hum from speakers at close range is fairly normal. Soft hum at your listening range is annoying but happens in some systems. Loud hum at your listening position could indicate a power problem. Which do you have?

Transformers normally don't make much noise. A toroid should be very quiet and the rest will hum but should not buzz. If all your transformers are noisy and if you can hear them at a distance from your system it's odd.

If you have a really bad wave form on your AC it could cause buzz. If your AC voltage is also way out, it could cause problems. A house power supply this bad seems unlikely and the parrot isn't out of the picture but .... enjoy your weekend and we'll all be interested to hear the results.

Jules

dogorman · « **Reply #47 on:** 19 Mar 2009, 11:42 pm »

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 http://img21.imageshack.us/gal.php?g=electrics002.jpghere. 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)

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).

dogorman · « **Reply #48 on:** 17 Apr 2009, 06:07 pm »

Just a quick bump to this thread -- with some new info to report:

1) The "stripped down" rig, consisting only of CDP, preamp, and power amp, connected on the same (dedicated) AC-line, evidenced the same problems as before.

2) My electrician-friend thinks grounding issues will be easier to check than dc-offset, which suggests he doesn't have the equipment to check the latter at his disposal.

3) The breaking-IC connections and re-establishing them turns out to be a red herring: It's the *POWER* connections that have to be disconnected and reestablished, only. I'd been disconnecting all the components from AC power in order to swap-out IC's, and the IC reconnections were getting the credit for the improvement.

4) The CD-player transformer doesn't just get extremely hot, it also has an audible hum which I'd never noticed before this most recent round of tests. So the amp and the CD-player are both humming from inside their respective chassis.

5) I installed Xitel ground loop isolators between the CDP, preamp, and power amp, with no improvement.

Follow-up thoughts are welcome and appreciated as always. Are we perhaps zero'ing in on DC-offset?

BradJudy · « **Reply #49 on:** 17 Apr 2009, 06:23 pm »

You could try the DIY DC blocker circuit mentioned in the lab a few times, or a commercial product that blocks DC on power lines (the Channel Islands XDC-2 is one). If there's noticeable heat/hum from the transformer, then it should be a quick test.

dogorman · « **Reply #50 on:** 17 Apr 2009, 07:32 pm »

I've been cruising the search pages for a concise thread that describes the construction of the most-recent "felix" d-i-y project, complete with dc-blocker, and I've just gotten more and more confused because the search engine doesn't prioritize threads about this subject ahead of single posts. It appears as though the current thinking among the d-i-y'ers in here is that a felix with integrated dc blocker and switching power supply is the way to go. I'm not a d-i-y'er but I could either learn or have someone build this thing for me, either of which would be preferable to shelling-out a bunch of markup for another off-the-shelf product.

Can someone post a link to the definitive, SOTA thread about this project, is someone interested in building one for me, and should I include enough outlets to run cdp, preamp, *and* power amp, or leave the power amp connected directly to the wall?

richidoo · « **Reply #51 on:** 17 Apr 2009, 08:32 pm »

Hi dogorman, glad to see you're still getting after it! I was told in the Lab that checking for DC offset requires an oscilloscope. The troubleshooter from the utility will have the right tools.

Here is a DC blocker circuit, courtesy Gordy/Occam/Bryston. It is simple and easy to build. Should cost $30 parts, put into a plastic box lumped into an extension cord. Don't worry about audiophile parts, just use it to block DC for a test. You don't need the Felix part to block any offset.

http://www.audiocircle.com/index.php?topic=58879.msg522767#msg522767

konut · « **Reply #52 on:** 17 Apr 2009, 09:08 pm »

Have you called your electric utility company yet?

dogorman · « **Reply #53 on:** 17 Apr 2009, 09:36 pm »

Yes -- so far no reply.

dogorman · « **Reply #54 on:** 17 Apr 2009, 11:24 pm »

Richido, do you or anyone else have the list of values for all the parts in that dc-blocker? I can have a neighbor across the street (grad student in EE) build this, but I know before I ask that he'll tell me he needs all the values.

konut · « **Reply #55 on:** 17 Apr 2009, 11:25 pm »

I know its a pain on the butt, but keep calling until they come out. Eventually they get tired of the calls and come out just to shut you up.

BradJudy · « **Reply #56 on:** 17 Apr 2009, 11:51 pm »

This thread discussed some specific parts - http://www.audiocircle.com/index.php?topic=50908.0

jules · « **Reply #57 on:** 21 Apr 2009, 07:10 am »

It might be worth contacting AC member "Occam" directly about this. He designed the Felix [or is it Felicia?] and is very knowledgeable when it comes to power supply matters.

Quote

4) The CD-player transformer doesn't just get extremely hot, it also has an audible hum which I'd never noticed before this most recent round of tests. So the amp and the CD-player are both humming from inside their respective chassis.

How hot is "extremely hot"?

Some hum is normal from some types of transformer, though if your CDP uses a toroid and it hums to an extent that is audible at distance from the source and it gets too hot to touch, you've got a problem but you're getting closer to knowing what it is.

Jules

dogorman · « **Reply #58 on:** 21 Apr 2009, 12:44 pm »

"How hot is extremely hot?"

After it's been running for an hour, if I touch the RCA terminals they feel roughly the same as the outside of a mug of hot coffee.

jules · « **Reply #59 on:** 21 Apr 2009, 11:40 pm »

Quote

if I touch the RCA terminals they feel roughly the same as the outside of a mug of hot coffee.

Wow, particularly if you're talking about a CDP!

You might find it interesting to read his thread:

http://www.audiocircle.com/index.php?topic=67218.msg621473;topicseen#new

The poster seems to be suffering from a power supply problem and ScottF has given him some great tech advice that could be worth keeping in mind if you get some testing done by your supplier.

Jules