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Poll - Ground Issues?

Posted: 05 Mar 2018 22:40
by Legrace
In my case #3. Otherwise suffer insufferable hum levels, or in the case of one component have my GFCI trip routinely. Meanwhile my vintage devices supplied with 2 prong plugs cause zero issues. Why are 3 prong plugs so problematic in hifi systems?

Re: Poll - Ground Issues?

Posted: 06 Mar 2018 00:54
by jdjohn
Is #3 supposed to say "3 or more"?

Re: Poll - Ground Issues?

Posted: 06 Mar 2018 06:59
by Legrace
Is #3 supposed to say "3 or more"?
Yes I suppose it should. Should have also included a zero option. Not on the ball when I set that up. :oops:

Asking as was wondering how many others struggle with ground loops and the extent component wise. As the number of components in my system has proliferated an issue that bedevils me. Really hate that induced hum noise. Floating grounds is one solution, but in the best interests of safety would actually prefer another solution. Some kind of ground manager gizmo. Anyone know of and can suggest an effective device?

Re: Poll - Ground Issues?

Posted: 06 Mar 2018 09:23
by tlscapital
Legrace wrote:
Is #3 supposed to say "3 or more"?
Yes I suppose it should. Should have also included a zero option. Not on the ball when I set that up. :oops:

Asking as was wondering how many others struggle with ground loops and the extent component wise. As the number of components in my system has proliferated an issue that bedevils me. Really hate that induced hum noise. Floating grounds is one solution, but in the best interests of safety would actually prefer another solution. Some kind of ground manager gizmo. Anyone know of and can suggest an effective device?
That would have get my vote :mrgreen: And no hum at all since I cleaned-up all the ground cables connection points on the tonearm and turntable chassis. I use to have some hum and then my sound was not as clear and deep as it is now since the re-wiring/cabling of the tonearm and recap of the speakers !

Re: Poll - Ground Issues?

Posted: 06 Mar 2018 17:24
by analogaudio
The vast majority of hifi gear uses unbalanced connections for the audio signals, a single wire for the signal and a shield for the ground return. This method is satisfactory for systems that comprise few units. This has encouraged the use of unbalanced connections in hifi for decades. One of the advantages is the low cost of the connectors and cable and the simplicity (and hence low cost) of the audio circuits at each end of the link. Unfortunately this system is inherently vulnerable to hum problems due to the dual use of the audio return connection as both a shield and a ground. Loops are created, sometimes multiple loops. The cause is not defective cables or connections it is the physics of multiple ground paths that exist.

There is a remedy, it has been used by broadcasters, recording studios, film and TV studios, and everywhere else that quality comes before price, the remedy is the balanced audio connection system. Two signal wires are used plus the shield, this requires 3 circuit connectors which are bulky heavy and expensive compared to the old RCA terminal, the most common type is the "XLR" system. This system permits the separation of the two functions of shielding and grounding, which, when done with the necessary attention to detail can achieve hum free operation. Note that among the details is the requirement to deal with what is known as the "pin 1 problem" which requires each item to examined for the way it is grounded by the manufacturer and sometimes requires modification to be made.

This subject has been studied in professional audio, one of the helpful sources of technical guidance is the website of the manufacturer RANE, they have published write-ups on the subject that are free and may help the newcomer:

http://www.rane.com/library.html

Attempts to "de-hum" a typical unbalanced hifi system can be frustrating because any change to the system, for example by adding an item, the hum may return.

Removal of safety grounds (chassis connections) is unwise. An alternative is the disconnection of the shield at one end of the interconnect cable, either by modifying the cable, or by isolating the ground connection of the terminal inside the item.

Re: Poll - Ground Issues?

Posted: 06 Mar 2018 18:54
by JoeE SP9
The only device I own/use that has ground issues is my TT. Connecting the ground wire to my preamp takes care of that.

Re: Poll - Ground Issues?

Posted: 06 Mar 2018 19:28
by Legrace
Analogaudio thanks for your reply, very educational. Except few of my components feature XLR connections. Only my integrated amp. Main culprits are my monoblock tube amps which I really dont want to replace as I really like the way they sound. Too bad those XLR's are not more standardized. :cry:

Re: Poll - Ground Issues?

Posted: 07 Mar 2018 04:31
by djcoma
analogaudio wrote:The vast majority of hifi gear uses unbalanced connections for the audio signals, a single wire for the signal and a shield for the ground return. This method is satisfactory for systems that comprise few units. This has encouraged the use of unbalanced connections in hifi for decades. One of the advantages is the low cost of the connectors and cable and the simplicity (and hence low cost) of the audio circuits at each end of the link. Unfortunately this system is inherently vulnerable to hum problems due to the dual use of the audio return connection as both a shield and a ground. Loops are created, sometimes multiple loops. The cause is not defective cables or connections it is the physics of multiple ground paths that exist.
You nailed it Ted. That is exactly what separates consumer electronics -aka "Hi-Fi"- from pro audio.
No matter how expensive the equipment, the inherent design flaws break down at a very basic level.
$500+ unobtanium coated RCA/speaker wires aren’t going to solve or minimize these problems; however, many "HI-FI'ers" are deeply entrenched and addicted to the placebo effect that marketing provides.

I also concur that removing a grounded chassis is not wise decision at all. Troubleshooting and removing the loop source is what should be done.

""Why are 3 prong plugs so problematic in hifi systems?"" Some equipment have the neutral and chassis ground wired together. This can cause a return current and therefore tripping a GFCI.

http://www.fluke.com/fluke/uses/comunid ... host-trips

Re: Poll - Ground Issues?

Posted: 07 Mar 2018 12:16
by P700DEE
I run balanced mains (transformer) so no Hum issues.

Re: Poll - Ground Issues?

Posted: 07 Mar 2018 13:09
by VinyldechezPierre
analogaudio wrote:The vast majority of hifi gear uses unbalanced connections for the audio signals, a single wire for the signal and a shield for the ground return. This method is satisfactory for systems that comprise few units.
What is "few units"?

I now have 6 units + 2 lights on the same outlet strip and no ground problem. Of the two turntables, one is grounded through a ground cable attached to the ground screw on the back of the pre-amp, the other one is grounded through the RCA plugs.

The rest of the gear, only one unit is grounded through a 3-prong plug. To be honest, I don't understand enough about french electricity to say that 2-prong means no ground whatsoever.

Anyway, I guess it means I plugged everything in the way it comes: 2 or 3-prong plugs and separate ground cable for one TT. And I have no hum.

Re: Poll - Ground Issues?

Posted: 07 Mar 2018 21:59
by jdjohn
Hey @Legrace, is it where your monoblock tube amps are in the chain that you get the hum? I know tubes can sometimes cause grounding/hum issues where solid-state does not.

Re: Poll - Ground Issues?

Posted: 07 Mar 2018 23:37
by Legrace
jdjohn wrote:Hey @Legrace, is it where your monoblock tube amps are in the chain that you get the hum? I know tubes can sometimes cause grounding/hum issues where solid-state does not.
Correct, prior to the tube amps I had zero hum issues. Only on floating the tube grounds does the hum completely disappear. Would prefer an alternate solution, just dont know what this might be?

The other situation is unrelated to hum. I have a Japanese spec piece that has a 2 prong plug + separate ground wire in place of a third prong. There is also a ground wire coming from the tonearm. Hooking up the power source ground wire to my amp chassis ground screw causes my GFIC to trip. Should I be connecting it elsewhere, or simply leave dangling? (current case)

The whole issue of grounding seems so confusing. :?

Re: Poll - Ground Issues?

Posted: 08 Mar 2018 03:41
by jdjohn
Legrace wrote:Correct, prior to the tube amps I had zero hum issues. Only on floating the tube grounds does the hum completely disappear. Would prefer an alternate solution, just dont know what this might be?

The other situation is unrelated to hum. I have a Japanese spec piece that has a 2 prong plug + separate ground wire in place of a third prong. There is also a ground wire coming from the tonearm. Hooking up the power source ground wire to my amp chassis ground screw causes my GFIC to trip. Should I be connecting it elsewhere, or simply leave dangling? (current case)

The whole issue of grounding seems so confusing. :?
With all inputs disconnected from your tube amp, does it still hum through the speakers? If not, clearly it's one of the inputs causing the problem. If it still hums with no inputs connected, you know it's the tube amp itself.

Regarding your Japanese spec piece, it would seem that the amp chassis is charged/shorted somehow, so when you connect a ground to it...poof.

Are you using a power conditioner?

Also, is there any fluorescent lighting near your tube amp, or on the same circuit? Dimmers?

Re: Poll - Ground Issues?

Posted: 08 Mar 2018 04:26
by Spinner45
The only "added" grounding on my main system is the turntable-to-receiver ground.
The whole system is dead silent, no hums, no hiss, no nothing, except music comes from the speakers.

*Turntable
*Receiver
*CD player
*cassette deck
*reel to reel
*SRS processor
*speakers.

No noise!

Re: Poll - Ground Issues?

Posted: 14 Mar 2018 08:58
by Wimbo
djcoma wrote:
analogaudio wrote:The vast majority of hifi gear uses unbalanced connections for the audio signals, a single wire for the signal and a shield for the ground return. This method is satisfactory for systems that comprise few units. This has encouraged the use of unbalanced connections in hifi for decades. One of the advantages is the low cost of the connectors and cable and the simplicity (and hence low cost) of the audio circuits at each end of the link. Unfortunately this system is inherently vulnerable to hum problems due to the dual use of the audio return connection as both a shield and a ground. Loops are created, sometimes multiple loops. The cause is not defective cables or connections it is the physics of multiple ground paths that exist.
You nailed it Ted. That is exactly what separates consumer electronics -aka "Hi-Fi"- from pro audio.
No matter how expensive the equipment, the inherent design flaws break down at a very basic level.
$500+ unobtanium coated RCA/speaker wires aren’t going to solve or minimize these problems; however, many "HI-FI'ers" are deeply entrenched and addicted to the placebo effect that marketing provides.

I also concur that removing a grounded chassis is not wise decision at all. Troubleshooting and removing the loop source is what should be done.

""Why are 3 prong plugs so problematic in hifi systems?"" Some equipment have the neutral and chassis ground wired together. This can cause a return current and therefore tripping a GFCI.

http://www.fluke.com/fluke/uses/comunid ... host-trips
A hell of a lot of serious "Audiophiles" look at this problem as Phase 1.
just help the OP if you can with advice.