Dare I ask for Electrical Help??? (ducking).... Major Hum

[meagain]

So.... I'm trying to puzzle out a LOUD hum that developed out of nowhere. The only thing that changed was my husband put on a metal outlet cover. The hum started around that time so I thought perhaps the metal was creating some type of weird situation so I removed it. Still hum (or hum/buzz sound).

It sounds like when I had an issue 1-2 years ago with a ground loop problem that Mark Deneen helped me with by suggesting cheater plugs. But that was when I first installed some gear and it made sense. All the gear is on a Furman voltage regulator. This Furman is plugged straight into the outlet. The outlet on this circuit (now) only has a rarely used lamp on it. This outlet reads as "correct" with a "is it grounded?" tester.

This hum is only an issue when the Peach is on HT bypass. When on Hi or Lo-z, it is still there but FAR less and I can deal with it (for now).... The hum doesn't change with turning the volume on the Peach. When in HT bypass, the hum comes out of the VRDs (2 front mains). There is no hum in the center or rears. This is odd to me. When I pull out the cords from the HT bypass slots in the Peach to the Harman AVR - Hum stops. Hum is equal on both sides. OK - Husband just came home and confirmed he didn't mess around with cords, etc. ???? I'm confused as to what happened, and why the hum is only in the 2 mains. But am I looking at a cord interferance issue here? Does that sound about right? Tho' I'm perplexed as to 'why'?

Thanks for any thoughts!

[oldtimer]

What mdeneen said but also, have you considered that, perhaps you live in a region seldom frequented by the vast majority of us, a region that's called "the twilight zone."

[meagain]

Take the output of the AVR that would normally be plugged into the HT IN of the Peach, and plug this pair directly into your VRD. Result?

Unplugged the HT cords from the HT in of Peach and plugged into VRDs. So the cords go from AVR to VRDs. (if that's what you mean).

Result: Still hum. AVR is turned off. Hubby just grabbed another set of cable - way worse. So - Even with AVR off - Major hum.

[meagain]

What mdeneen said but also, have you considered that, perhaps you live in a region seldom frequented by the vast majority of us, a region that's called "the twilight zone."

That was already determined as fact about 2 years ago.

[oldtimer]

You crack me up, and that's good enough for me.

[Guest " "]

So I assume you tried a different outlet....you did say it started when the cover was replaced on the current outlet....

If different outlet works.....that would take things to a different direction....different meaning an outlet that has never been uncovered.

[DrWho]

Just unplug the amps...guaranteed no hum []

[meagain]

No, I didn't plug into another outlet cuz 1/2 of it works fine (non HT bypass). Plus I took that cover off the outlet back to like it was which made no difference. I.e.; if the outlet failed, why wouldn't 'all' the speakers hum?

[mas]

Lifting the ground interrupts the circuit, and as such
it would alleviate the noise problem. But while it solves one problem,
it creates a much worse one - if a ground-lifted device develops a
short or fails, the interconnection cables will carry lethal voltages
through the system and/or start a fire.

We can all guess as to the source of a problem that evidently has no cause (nothing changed!), or one can sytematically examine the environment.

Here is a troubleshooting guide by the guru of grounding and noise issues.

It refers to ISOMax isolation transformers, but the procedure is universal. Be aware that the wide-band isolation transformers.are available individually and the entire kit is not necessary. But again, the procedure is universal.

Although it is perhaps not as much fun as simply guessing and arbitrarily changing things in a haphazard way such that, even if successful, the solution remains as mysterious for why it worked as why the problem developed.

But then...come to think of it, what could be more 'audiophile' than that?

ISOMax.TS_guide.2.pdf

[meagain]

So now - We tested the Jolida CDP - Peach - VRD combo and no sound. No lie. It now appears the cable is bad from Peach to ONE VRD is bad? Like - seriously? Since when? It's the connection of this cable to the VRD. Maybe the VRD connection? Trying another cable. Amazingly, did another problem just develop separate from the hum? This would not surprise me. OR....... could this Peach to VRD cable have been going bad and somehow that cable being tied to the system "created" the hum? Another cable is working. Will try to see if Hum is on HT bypass again.

[meagain]

Still Hum.

[meagain]

So is it safe to say the pre-amp out ports on my AVR inexplicably became defective? Uh - No. Plugged cord from AVR into digital amp. No hum. Moved from digital amp to VRD - Hum. I'm confused. Maybe digital amps being different and all - aren't capable of humming? Guess no concert DVD for me tonight.

[mas]

So is it safe to say the pre-amp out
ports on my AVR inexplicably became defective? Uh - No. Plugged
cord from AVR into digital amp. No hum. Moved from digital amp to VRD
- Hum. I'm confused. Maybe digital amps being different and all -
aren't capable of humming? Guess no concert DVD for me tonight.

No its not safe to say that.

Apparently you have a difference in ground potential between the two units.

Follow
the procedure as defined in the PDF and be sure to first REMOVE any of
the ridiculous ground lifts that may have been installed which only
mask the problem and will cause problems in identifying the real
causes.

[Coytee]

Don't you have Craig's phone number?

[6]

[oldbuckster]

Coytee, you're a mean man !!!!!!!!!!!!! (snicker,snicker) ... Dam Mean!!!!!!!!!

[NOSValves]

Don't you have Craig's phone number?

I have her on my block list []

[J.4knee]

buy an iPod and a set of Custom3 headphones yer hum will go away regadless fo how you configure your systems and that silly differntial ground potential won't bother you either.[6]