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I've been trying to track down a ground loop issue on the system I host on Friday nights (not my equipment). I have concluded that the ground loop hum happens when the power supply to my laptop is plugged in. Run the laptop on the battery, ground loop hum goes down (but there is a very minor hum still there which tells me there are other issues).

I know what needs to be done for a long term fix and can weigh my options, but I need to come up with a band-aid fix quick and dirty in the next, errr, seven to eight hours. Here is my question and I understand I am taking a 1% risk of blowing up my laptop if there were some voltage spike. If I get an adapter that converts the grounded three prong plug to a two prong, essentially, eliminating the ground, will the ground loop hum go away (my guess is no and more is at work than the third prong ground)

Again, this is just my solution for tonight - I simply do not have the time to explain to the owners and then go through and isolate the other problem in the equation to close off the other end of the loop. My guess is the issue is largely caused by there are a ton of grounded plugs on the same circuit and although key pieces go through a regulator, not all components (including lighting) do and there are two power strips worth of other items plugged in on what is probably, the same grossly overloaded circuit.

Any feedback appreciated!

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Despite the internet rumor, Karaoke is not Japanese for "drunk buffoon with microphone."  However, "rotation," is Japanese for wait your damn turn!

might try looking at a hum eliminator like this:
http://www.audiomidi.com/common/cfm/pro ... m?pid=4803

That one will work if the laptop is grounded & it's a safe alternative to eliminating the ground prong. Otherwise you may look at this one as well.

http://www.audiomidi.com/common/cfm/product.cfm?pid=314

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

Ooops.

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

I use an adapter (3 prong to 2 Prong) all the time due to the same exact problem ...Ive been doing this for about a year now and no problems yet. I figger the power supply will blow before my laptop does. might be wrong but so far it's been fine.

Quick, dirty, band-aid fix?

http://www.radioshack.com/product.asp?c ... id=270-054

$16.99 at your local radio shack. I sometimes use my home tv which gets a bad hum from a ground loop. Slapped two of these in and the problem disappeared completely.

Comes with an adapter to connect the RCA connections on the ground loop isolator to 1/8" TRS so you need nothing else.

BTW, I'd recommend something from the sponsors but I didn't find any ground loop isolators or hum eliminators on their web sites.

Yes it will work, but it's not SAFE!

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

Thanks everyone for the advice. Going to the the X Hum but I needed a solution in my hand that night - so I went the Home Depot 99 cent route for last night and got a three prong to two prong adapter.

Will not make it my long term solution. For my own equipment I will keep it with my cables. Never know...

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Despite the internet rumor, Karaoke is not Japanese for "drunk buffoon with microphone."  However, "rotation," is Japanese for wait your damn turn!

The problem is that when you lift the ground you create the potential for a serious shock hazard.

If you ever saw the movie 'The Commitments' there was a scene in there where the bass player gets the - well, let's just say he gets shocked enough to knock him unconcious. Yes, it's in a movie. But IRL he'd more likely be dead.

It's less common now, but there was a time you had to be careful because ground isn't always ground. Chassis ground, electrical ground, signal ground, and AC neutral can all be VERY different things with large amounts of signal differential - enough to kill you if you're not careful.

And there are those that say it's completely safe. I'm not willing to risk my life on the possibility that it 'might' be safe when there is a safe economical solution. BTW, I keep a couple of those Radio Shack cords in my gig bag. I'll probably pick up an XLR based hum eliminator shortly to add as well. It's less than $100 for the lot and I'll never have to worry about it again.

Not that this has a whole lot of bearing on this conversation but I'm on my fifth laptop computer now and up until my very newest one none of them even had a ground on the power supply. Oh yeah and my newest one is the only one that ever had problems with noise from the soundcard. So I say go ahead and lift the ground. I've been doing it with my newest laptop for a couple of months and I'm still alive.

If the laptop doesn't have a ground plug then using the 3-pront -> 2-prong adapter shouldn't affect anything - including the noise caused the by ground loop.

My lap top DOES have a three prong plug...the 3 to 2 made it go away...but again, strictly a band-aid.

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Despite the internet rumor, Karaoke is not Japanese for "drunk buffoon with microphone."  However, "rotation," is Japanese for wait your damn turn!

Along with the item that lonman mentioned Eb-tech has another item designed to remove ground hums.
You can check it out at the link below.


http://www.musiciansfriend.com/srs7/g=h ... id/150452/

That item was brought up in post number 2.

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LIKE Lonman on Facebook - Lonman Productions Karaoke & my main site via my profile!

Your right and it was cheaper as well.

Speaking of ground loop hums, I just picked one up a couple weeks ago at our normal spot we KJ at. We use to have a hum on our powered speaker we used for our monitor, but 2 weeks ago after adding in a few new items in our rack we had an awful hum. The owner of the bar always gets there late so we didn't have much time to search it out, we had to get on with the show.
While running the show one of the regulars checked out a few things that were on like lighting etc. The stage lights and dimmers were a big problem and sfter the show we cut the ceiling fans that were running in the pool table section and that cut all the noise. I thought maybe the furman line conditioner I was waiting for might do the trick.
When I got home I set back up using the 100' snake and the other cables that had been used at the Club. Dead sillent, just a slight hiss if you put your ear against the speaker. That weekend we set up in a differant location for a private party the sound was just a quiet as it was in my garage. Last thursday after instaling the line conditioner we went down to do the show. Same problem as the week before. So I started changing things until I found the problem, it was the Crossover that was in the rack on stage at the other end of the snake. The crossover did not give problems anywhere but at the club we usually host at. This was a new item. What tipped me was the fact that the stage monitor that gets its signal through the same snake and the other side of the same amp was dead quiet. Every cable was balanced connection and the inputs and outputs of the crossover are also balanced. (so the MFG. says)
Well this week I will try the Ebtech 2 channel hum eliminator that I ordered after last weeks episode.
I'll let you know what happens.

The hum is completely gone, they can turn on anything they want and all I get out of my speakers if I put my ear against it is a slight hiss, it can't be heard from more than 2 feet away.

I've been so busy so I haven't updated on my situation.  It seems as though the manager of the club also noticed the ground loop and it was isolated - so regardless of my solutions the problem is now fixed.  I am using the RadioShack ground loop isolator and I am so impressed!    :shock:  :shock: I kind of have a dim view of RadioShack components and I was concerned on how much signal it would rob, but it just plain works.

Thanks for all the great suggestions - this site ROCKS (literally and figuratively)

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Despite the internet rumor, Karaoke is not Japanese for "drunk buffoon with microphone."  However, "rotation," is Japanese for wait your damn turn!

Here is a good link on ground loops Ive used for a few years...

    www.rane.com/note110.html

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I worked at Radio Shack for a number of years and have a low opinion of some of the equipment they make.  Some of the HAM radio equipment was pretty decent and got regular writeups that were full of praise.  Fortunately, this $15 ground loop isolator fix works VERY well and it's a good idea to keep on in your kit for unbalanced connections.