Grounding problem with a dedicated line?

Bill, you bring up some excellent points. My original set up was just the amps running off the dedicated line( I only have one 20 amp dedicated line with a dual gang outlet) and all the other gear running off the 15 amp convenience line.
Now, with the Rowland, I am forced back to the original set up...since the beast pulls 100 watts at idle,300 watts at operating standby and 1200 watts maximum. Therefore, it will run solely off the dedicated line and everything else will be relegated to the convenience line, luckily and in some ways oddly, the grounding issue doesn’t seem to be an issue with Rowland/ Esoteric set up that way. The Jadis pulls 125 watts max per mono block...so far less than the ss beast. I noticed no issues with it and all the other gear off the strip and then plugged into the dedicated line.
Your question about multiple dedicated lines and grounding potential differences is one that I question also...hopefully one of the more technical folks on this thread can answer that.
In the future, I am going to look into a power conditioner...something that Jeff Rowland told me is not ideal for his bigger amps, but perhaps some of the latest ones would be a more favorable solution. At least with PC’s I can audition and see if they do in fact improve, or negatively impact, the SQ.

 

The rare instance when 'buzzkill' is a good thing....

 

No you were not wrong. The circuit ground connection to the equipment grounded chassis grounding design of the Jadis amps contributed to Dave's problem with the buzzing sound of his audio system heard through the speakers. (Ralph K posted the Jadis amps circuit ground is directly connected to the equipment grounded chassis.)

Proof?
Actual hands on testing.
With the Jadis amps removed from the system and the Rowland amp installed in the system the ground loop circuit was broken. No buzzing sound. (It takes two to Tango. The Jadis amps and the Esoteric SACD player)

Convenience circuit wall outlet equipment ground >>Esoteric SACD >> preamp >> Rowland amp.>> Dedicated circuit wall outlet equipment ground.

From actual hands on testing the Esoteric SACD also causes ground loop buzzing when it is connected to the Jadis amps through the preamp. Therein , a good chance, the circuit ground design directly connects the circuit ground to the equipment grounded chassis of the SACD player.

Actual tests preformed:
Ground cheater was installed on the power cord of the SACD Player and broke/opened the ground loop stopping the buzzing sound.
Yeah but so did installing ground cheaters on the power cords of the Jadis amps. True, the ground loop circuit was broke/opened stopping the buzzing sound.

So why say the Esoteric SACD is at fault as well as the Jadis amps circuit grounding design?

The preamp.....

The preamp was plugged into the convenience circuit wall outlet during all the testing using the Jadis amps . The preamp circuit ground design to equipment grounded chassis does not directly connect the circuit ground to the equipment grounded power supply chassis. If the circuit ground was directly connected to the power supply chassis, of the preamp, there still would have been a ground loop/buzz when a ground cheater was installed on the SACD or when the SACD was unplugged from the wall outlet.

If we are to assume/agree that the circuit ground is directly connected to the equipment grounded chassis of both the Esoteric SACD player and Jadis amps then a direct ground loop circuit path is provided, (IF a difference of potential, voltage, exists between the 2 branch circuit equipment grounding conductors), for ground loop current to travel through the circuit ground of the audio equipment causing a buzzing sound heard through the speakers.



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Dave,

Does the duplex outlet have an orange shaped triangle on the face of it? Or the outlet face is orange in color with a triangle on the face as well.
Examples:

Hubbell Wiring Device - Kellems IG5362W HBL® Isolated Ground Duplex Receptacle, Extra Heavy Duty Specification Grade, 20A, 125V, 2P3W, White | Graybar Store

HUBBELL IG5362 AC Receptacle NEMA 5-15/20 Female Orange Duplex Isolated Ground

IG5362 | WDK | Brand | Wiring Device - Kellems

Why did you have the electrician install an IG, (Isolated Ground), type grounding duplex receptacle outlet?

Dave,

Did you buy a multimeter as I suggested in one of my posts to this thread?

You need to buy a descent meter. You should be able to buy a descent one for $50.00.

 

Jim, that is the type of outlet that is in use at the dedicated line. Supposedly hospital grade. I am considering replacing it with a four (4) gang outlet...probably one of the Furutech models. ( I think that would require two side by side two gang outlets, as i don't think Furutech actually make a four gang) The wiring in the wall is 10/2 Romex. Maybe also change the twenty amp breaker to a thirty amp breaker??

 

Yeah, fair enough. I thought about that. What I didn't expect is that plugging everything into the same circuit would eliminate the hum.

 

Jim,

The Esoteric has a separate signal grounding lug on the back of the chassis. I am not using this for anything, Is there a way to use that connection and ground the SACD player without utilizing it on the same circuit as the rest of the gear? I presume that Esoteric have this option ( on all of their players) for some reason. Says nothing about it in the manual!

 

Great news that the hum/ buzz has been eliminated, if I understand correctly.

DaveyF, what is your path forward? What are you planning as far as power distribution...leave well enough alone? Upgrade
the strip? PC?

This has been interesting to follow, thanks.

 

If that is the case, then this hum was not due to a ground loop.

@jea48 had good advice about getting a Digital VoltMeter (DVM). You could get to the bottom of this quite quickly- if you want to. At this point, since the problem seems to be sorted then you might not consider it worth it. But your dedicated line, if wired to code, should present all the same conditions that allow for a ground loop. Assuming that the Jadis is wired as presented in a schematic shown earlier (as well as the Esoteric, yada yada...) then the ground loop would have manifested. Since it did not, the conclusions are that the equipment is in fact not inappropriately grounded at all and thus the hum was not due to ground loop. A DVM would allow you to sort that our in a short order.

 

Ralph, I am probably not getting a DVM. I will have my electrician look at the outlet and am considering adding a four gang unit instead of the current two at the dedicated line. I don't think my Jadis is wired the same way as the JA80 in the example. Firstly mine is a JA30Mk2, a very recent model...and utilizes the new KT150 tubes ( which BTW, I highly recommend...after years of using 6550's, KT88's etc), secondly, I don't think that the Esoteric looks anything like the model presented up thread. Nonetheless, I am not understanding why you think a ground loop couldn't be caused by an imbalance between the circuits...as several other members suggested above.

 

Great question. Right now, I am probably going to leave alone...for the moment. I do plan on trying a few Power conditioners and possibly another power distributor. The Isotek, Audience , Bryston models come to mind...maybe a Shunyata?
I will not be plugging the TG audio power strip into the dedicated line when I am using the big ss Rowland....too much draw on the line. In that case, I will plug the Rowland into the dedicated line and everything else into the 15 amp convenience outlet. As to what to do with the dedicated line outlet, that is up in the air...I am contemplating replacing it with two Furutech outlets for a four gang set up and upgrading the breaker to a thirty (30) amp. That way, I could plug the Jadis mono blocks into the outlet and not have to use the strip for the amps. The other gear would go through a strip into the dedicated line. ( BTW, I am still quite pleased with the performance of the TG audio strip, I'm not sure any strip could deal with the load presented by the ss beast, LOL).

 

Why was an Isolated Ground, (IG), grounding type duplex receptacle used? What was the intended purpose for using the outlet?

(What is an IG, Isolated Ground, grounding type receptacle? A receptacle that has the equipment grounding contact isolated, insulated, from the metal supporting back strap of the receptacle.) An IG receptacle would not serve any purpose what so ever connected to Romex wiring. None.

BIG IMPORTANT question. How did the electrician treat the IG terminal/equipment ground contact of the duplex receptacle outlet? Where/what is the IG equipment grounding conductor connected, to?

Per NEC electrical safety code the outlet IG ground terminal connects to the bare #10 equipment grounding conductor of the Romex cable. The other end of the equipment grounding conductor, of the Romex cable, connects to the equipment ground bar in the electrical panel, the branch circuit is fed from. Is that what the electrician did? Are you sure? A member on Audiogon found the electrician he hired did not connect the bare grounding conductor to the equipment ground bar in the electrical panel and instead spliced an insulated ground wire to the bare equipment grounding conductor of the romex. The electrician drove a dedicated ground rod in the earth outside the house and connected the insulated ground wire to the separate dedicated ground rod.

Would this cause a difference of potential, voltage, between the correctly wired equipment ground of the convenience outlet branch circuit and the dedicated branch circuit equipment ground of separately dedicated ground rod connection. YES.

I am not saying that is what the electrician you hired did. He may have connected the bare equipment grounding conductor to the equipment ground bar in the electrical panel.
The electrician's installation of the Romex wiring and terminations could be fine. Nothing is wrong with the installation. (Though it should be asked how did the electrician ground the metal supporting back strap of the IG duplex receptacle? Has nothing to do with your ground loop problem though.)

Next place to look is the 15 amp convenience outlet branch circuit for the cause of the difference of potential, voltage, between the two equipment grounding conductors of the two branch circuits.

That's a NO, NO! You can't do that!

The branch circuit ampere rating is dictated by the breaker handle rating. The breaker handle ampere rating for the branch circuit is dictated by the NEMA 5-20R duplex receptacle manufacturer's ampere rating of 20 amps.

For what its worth the current carrying guts, contacts, inside a 15, 20, and 30 breaker are all the same. Only the trip units setting are different.



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I remember that the IG was used as it was a hospital grade outlet..however, I have no idea if it is correctly installed. My previous electrician installed it for me, along with a new 200 amp panel and grounding rod. I did check the outlet with a ground checker, and it seemed to be fine...as was the convenience outlet when checked.
I guess I am not going with a thirty amp breaker, as I don’t believe that either my current receptacle is designed for that...or the Furutech’s that are available. Oddly, I know of another a’phile friend who has thirty amp dedicated lines...all with twenty amp Furutech’s...hmm.

I’m going to have my electrician check the grounding hook up at the panel...I doubt it was done the way the other electrician did it with a splice to ground wire to connecting rod, but that’s definitely something to check. Will report back on this.

 

Its just logic. Ground loops occur when audio equipment is improperly grounded. Assuming your electrician did his job correctly, then whether on a dedicated line or not (a dedicated line is simply a line that has only one outlet and has its own breaker at the breaker box) the grounds would have behaved exactly the same way. Ergo: the equipment is properly grounded after all, meaning the hum was caused by something else.

OR:

If for some reason the grounds of the dedicated line are not handled correctly, its possible that the equipment simply isn't grounded at all. If that were the case, then no hum on the dedicated line. It would also be the case that the connection isn't safe- that a shock hazard could exist if something were damaged.

A DVM would allow you to sort this out.

 

Here is an example of just a hospital grade duplex receptacle outlet. The green dot on the outlet signifies it is a hospital grade.

NEW Hubbell HBL8300HI 20A 125V 2P3W Hospital Grade Duplex Receptacle Nema 5-20R 783585015675 | eBay

Here is an example of an IG hospital grade duplex receptacle outlet. Note the green dot (Hospital Grade), and the orange color face with a green triangle that signifies IG, Isolated Ground.

IG8300 | WDK | Brand | Wiring Device - Kellems



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Wouldn’t the issue show up on my ground checker if there was a faulty or no ground connection? The ground checker shows no issue on either outlet, convenience or dedicated.

 

Mine is the orange version.

 

A simple plug in circuit/polarity tester will not indicate/measure the conductivity integrity of the equipment ground. All it does is tell you if there is one, something, is present.

A multimeter will tell you so much more.




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Actually, I was thinking about Ralph’s response that the gear isn’t grounded...and this is why I was questioning why that wouldn’t show up on my ground tester. The gear may have a faulty ground design, but the outlet is surely either grounded or not...and wouldn’t this be determined sufficiently by the ground tester?

 

Yes, and you proved that when used a ground cheater to lift the equipment ground breaking the ground loop circuit stopping the hum/buzz. But like I said it doesn't tell you the conductivity or integrity of the ground. Many things can affect just how good of a low impedance/resistance equipment ground you have. Example, a loose and or corroded termination connection or a loose or corroded wire joint/splice.

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That depends on the outlet tester! So do many don't.

In a word, No. Doncha just love this stuff??

 

Yes, I am beginning to realize just how much I do love this stuff....not!

So, we potentially have a ground tester, that doesn’t necessarily test anything...well it does give me some pretty lights to look at on the end of the tester! Lol.

 

I've been thinking about this issue; for the ground loop to not manifest on the dedicated line (if it really is a ground loop) the outlet itself would have to be where the ground connection is bad. Now I think you also mentioned that all your gear was plugged into some sort of power strip? Jadis and all? If so, it might be the power strip that isn't grounded properly. And that might simply be because one of the outlets has a bad connection and its the one that the Esoteric or Jadis is on. Again, a DVM would allow you to sort this sort of stuff really quickly.

 

Ralph, the power strip is in action with the dedicated line. I have connected all of the gear to the strip, per Jea48's recommendation. The problem with the buzzing has gone. Before, i was plugging the mono blocks into the dedicated line and everything else, via the strip, into the convenience line. This is when I was experiencing the issue, but only with the Esoteric and the Jadis....not when I used the Rowland and the Esoteric...the Rowland on the dedicated line and the rest through the strip into the convenience line.
Surely it must be a ground loop, as when I used the ground cheaters...either on the Esoteric or on the Jadis, the dreaded buzzing goes away. This when I was using the convenience line and the dedicated line.

Here's a question, could it be the outlet at the convenience line is no good? Tonight, I am having a good friend over, he is also an electrician..so hopefully some questions will be answered.

 

Dave you can plug the circuit/polarity checker into the TG power distributor to verify it has a ground. The tester will indicate CORRECT if there is a ground an the AC polarity is correct.

Please, please, please, tell your friend to bring his multimeter!

Things to have your friend, the electrician, check:

* Check the dedicated branch circuit terminations in the electrical panel. Have him verify the bare #10 equipment grounding conductor is connected to the equipment ground bar in the panel

* Have him pull the dedicated branch circuit duplex receptacle outlet from the wall box and verify the connections are all tight. If the box is made of steel make sure that it is grounded, connected, to the #10 equipment grounding conductor.


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