Jump to content


Please note: You can easily log in to MPN using your Facebook account!

Help, suddenly got hum (groundloop) problem and need a temporary fix!


Recommended Posts

Holy shit, after running my studio in the same location for 3 years, I've suddenly got hum in everything. Especially guitar amps. I have a do-or-die tomorrow with a client and need a quick fix. What about that simple 2 prong to 3 prong AC power adapter that drops your ground? I'm totally in panic mode. HELP!!!!!!!!!
No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites



  • Replies 17
  • Created
  • Last Reply

This just happened out of nowhere??? :confused:

 

What's different from yesterday?

 

No new gear? Did somebody else switch something around? Rodents?

 

Has bad weather messed with the power or power lines?

 

Have you powered EVERYTHING off and then back on again?

 

What the heck???

 

Good luck with this, Matt.

Link to comment
Share on other sites

I think you're one of 3 people on these forums that remembers my name. :D

 

I have tried everything, no changes. Weather may be to blame. Also, they (the city) just started construction on some big rec center less than half a block away. That may be where I need to place my blame. So what of the 2 prong to 3 prong adapter? Can it work, even for one day?

No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites

i highly doubt it. hopefully for you it MIGHT be one peice of gear or a combinatin of peices.

 

unplug everything, and plug it in one at a time until the loop happens. if you only have your mixer/amp hot and it buzzes you may have a problem that you cannot solve.

Link to comment
Share on other sites

Originally posted by Mr. Nice Crass Coaster Guy:

i highly doubt it. hopefully for you it MIGHT be one peice of gear or a combinatin of peices.

 

unplug everything, and plug it in one at a time until the loop happens. if you only have your mixer/amp hot and it buzzes you may have a problem that you cannot solve.

Yeah, I did that first. I'm boned. Nothing plugged in, nothing on. 'Cept amplifiers. One at a time, different rooms, different guitars, cables, outlets, outlets from extension cables, etc. I've tried everything. I can hear it in one of my sound cards also. Totally shitty. Just happened.
No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites

i hate to say it, but its the incoming power then. you may have a serious issue with voltage, floating voltage, or voltage differential.

 

the power company needs to come out and look at things (aint gonna happen)

 

or maybe you could get a power conditioner, or electric generator. either of these will set you back substantially. a generator that puts out clean power may well be over $1000 or even more.

Link to comment
Share on other sites

Crikey. That is a problem.

 

Do you have a good electronics supply shop near you (with a substantial amount of in-stock parts)? Are you handy with a soldering iron?

 

Here's a recipe for quick DIY line conditioners you can throw together in a jiff

 

http://www.geocities.com/jonrisch/surge.htm

Link to comment
Share on other sites

Don't know if this will help, or is in time...

Ground Lift Resource.

 

HERE"S another bit of information.

 

Jeez, I just, within the last couple of days, saw a really neat device for lifting ground loops. Maybe it was in the Sam Ash catalog, a GP issue or FOH, I'm not sure. I'll look around tonight when I get home & see if I can find it.

 

Our Joint

 

"When you come slam bang up against trouble, it never looks half as bad if you face up to it." The Duke...

Link to comment
Share on other sites

Since the problem exsists with only a single source, and you've got new construction 1/2 a block away, I suspect a chang ein your source power. Contact your local power company, and, assuming you are a registered business and not a pirate home studio, they should address your problem fairly qucikly, since obviously your business depends on clean power.

Hope this is helpful.

 

NP Recording Studios

Analog approach to digital recording.

Link to comment
Share on other sites

Is this studio in your home? If yes, is it tied into the main home power or do you have a separate feed? If they are on the same power feed, try checking audio through gear plugged into other outlets in your home. Also, be sure to check through headphones to know if this phenomenon only exists in your monitoring system. It could be something as simple as a blown component in your power amp.

 

If it IS on the line, have someone check the main feed for noise. If it doesn't exist outside your studio/home, then something's changed inside and needs to be addressed.

 

If you have access to a good size piece of copper tubing or pipe, dig a hole at least two feet deep and plant the rod outside the nearest window to the studio. Then attach your console ground to it as a makeshift ground rod. You'll may be surprised how this simple stop-gap measure works.

 

BTW - EVERY studio with access to the outside should have a real groundrod yielding true earth ground. Floating grounds and the OSHA ground (the third prong on American 110v plugs) often carry a voltage of as much as a few volts. This causes noise in audio gear.

It's easiest to find me on Facebook. Neil Bergman

 

Soundclick

fntstcsnd

Link to comment
Share on other sites

Originally posted by where02190:

Since the problem exsists with only a single source, and you've got new construction 1/2 a block away, I suspect a chang ein your source power. Contact your local power company, and, assuming you are a registered business and not a pirate home studio, they should address your problem fairly qucikly, since obviously your business depends on clean power.

Oops, I misread your post. You were spot on.
No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites

Have you tried (or is it possible) grounding the entire system as I outlined? I've done this in the past and it solved the problem immediately. It all depends on what in the power system is causing the buzz. Sometimes a solid ground will end these problems.

 

Also, you might try using a transfomer to isolate the ground, but it must be more than just a ground lift plug. That can be dangerous to your gear (And yourself!).

It's easiest to find me on Facebook. Neil Bergman

 

Soundclick

fntstcsnd

Link to comment
Share on other sites

Originally posted by fantasticsound:

Have you tried (or is it possible) grounding the entire system as I outlined? I've done this in the past and it solved the problem immediately. It all depends on what in the power system is causing the buzz. Sometimes a solid ground will end these problems.

 

Also, you might try using a transfomer to isolate the ground, but it must be more than just a ground lift plug. That can be dangerous to your gear (And yourself!).

It is possible, but I will not be able to try it for a few days. For now I'm just cancelling sessions.

 

I agree with you about the problems with just lifting the ground with an adapter. Looks like by cancelling the do or die session, I basically cancelled the remainder of the project and possibly have a group of unhappy customers. Nice that things like this only happen when you're on a timeframe so tight that you can't even breathe.

No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites

Okay, gone from hum to very loud BUZZZZZZZZZZZZZZZZZ on everything. Terrible sound. Impossible to do anything. I'm all over the power company and we'll hopefully get this solved soon. If anyone's been through anything similar it would be nice to hear how things turned out for you. Thanks for your suggestions everyone.
No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites

Look at the hum on a spectrum analyser. Is it mostly 60 Hz? or are there lots of strong harmonics?

 

If the harmonic content is really high, it's very likely that you need power line filtering. (There was a post guy who provided ae link to a power line filter - - it looked like a good design.)

 

This is common when a lot of loading without power factor correction is put on a power system. Examples are variable-speed motors (like power tools), dimmers, and large high-current power supplies (arc welders, for example).

 

Here are some things you can check first, though:

 

Disclaimer:

If you don't understand any of these terms or know how to do any of this stuff, hire someone who does! Hum is not worth getting electrocuted for! It is SO easy to die doing this; just one little slip is all it takes.

 

With that out of the way:

I'd start by checking that the safety ground still has continuity to the neutral line (10 ohms or less) on every outlet. Unplug everything from every outlet on that breaker before measuring it.

 

If it reads over 10 ohms or so, check other outlets that are fed from the other breakers.

 

If they all have the problem, you need to check your breaker box to make sure that the neutral & grounds are in proper order. The neutrals and grounds should all connect together in the box at a big copper bus-bar.

 

There should also be a large solid wire (10 or 12 gauge) that runs from the bus-bar to a true earth ground (either a cold-water pipe clamp, or a metal rod that is driven into the dirt outside the house. Check to make sure all these connections are electrically sound.

 

If all is in order, then the odds are fair that the nearby construction is a factor. It is likely that the loading on the AC phases are no longer balanced due to new loads being connected to the system.

 

The fastest cure is to go to a balanced-power conditioning system; other cheaper options (like a Furman box) may also work though.

 

Good Luck!

Link to comment
Share on other sites

Philbo, thanks. Yes it has LOTS of higher harmonics. Measures around -30dB @ unity?!?! :eek: The power company acted like it was an everyday occurance and assured me it would be solved promptly. This is Day 4 and I've heard nothing. Oh well, nice to have the time off, hehehe. Although I understand how to do what you suggest, I'm reluctant. I'll call someone as soon as the power co. makes their little trip over and tells me what's going on.
No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites

Originally posted by daklander:

You know, with all that, it sounds like the power company may have lost a leg, or a partail leg & you're on that side, or they've lost a neutral or ground.

That sounds like it translates to 'a long time' of waiting for a solution. ;)
No matter how good something is, there will always be someone blasting away on a forum somewhere about how much they hate it.
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...