Bad Hum....Help!!

Jon Light (deceased) · Post by **Jon Light (deceased)** » 5 Mar 2002 3:21 pm

I played the backroom of a bar Sunday nite that looked like it was wired by the owner's pet chimpanzee. I had an unbearable hum. I trouble-shot, step by step and established that the amp (Evans) was perfectly quiet. I cut my stomp boxes out of the chain and unplugged their wall wart. Just guitar to amp. The hum/buzz followed the volume pedal--pedal up, silent, pedal down, signal & buzz. Ground reverse on amp switch makes no difference. This is with a Lawrence 912. I'm set up at home now and everything is dead quiet. This sure sounds like a single coil type problem but like I said--Lawrence 912. I admit--I didn't think to move the guitar. But would that make a differnce with a humbucker?
Had to adjust my playing with the acoustic guitarist/singer-songwriter and lay back during the quieter stuff to avoid adding noise. Bummer. Any thoughts?

Tom Jordan · Post by **Tom Jordan** » 5 Mar 2002 3:31 pm

Jon, don't you just hate that? It was more than likely the neon or floresent lighting in the place..even considering the wiring job.

Enteresting, but my home is fairly modern and my wife decided to go to these new floresent screw-in bulbs and I get a very large hum if the the light near my guitar is on. I can shut the light off and use an end table regular light and it goes away.

I know of no cure for the hum other that keeping a 50" extension cord with you and trying the other available outlets.

Regards,

Tom Jordan

Jon Light (deceased) · Post by **Jon Light (deceased)** » 5 Mar 2002 3:36 pm

Yeah, my momma told me to stay out of barrooms. But I thought humbuckers were the solution. Does this mean that they aren't 100% effective in worst case scenarios?

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<center>FCarter U-12 7+8E
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Larry Bell · Post by **Larry Bell** » 5 Mar 2002 7:33 pm

Jon,
It's probably not just the pickup. As I'm sure you're aware, a lot of electronic equipment misbehaves when it doesn't get the proper voltage, or when there are ground problems. I've seen neon signs that could cause the ground to reverse. In this one place, my Twin would be perfectly quiet, then the sign would flicker and by the end of the set I had to flip the polarity switch. I wrestled with that all night. Nature of the beast.

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Larry Bell - email: larry@larrybell.org - gigs - Home Page
2000 Fessenden S-12 8x8, 1969 Emmons S-12 6x6, 1971 Emmons D-10 9x9, 1971 Dobro

Keith Hilton · Post by **Keith Hilton** » 5 Mar 2002 9:46 pm

I find this really interesting since your pickup was a humbucking pickup. Noise can be picked up in guitar cords, even well shielded ones. Example: Put a powered wall wart right next to your guitar cord and listen to the hum. Better yet, put a powered wall wart right next to your pickups and listen. Even though the guitar cord is shielded, there is inductance from the wall wart. That is why I have always believed a person should keep wall warts away from equipment and cords. Then you have guys who have power strips full of wall warts in a rack mounts right with their signal processors and get away with no hum. 120Volt AC circuit recepticals in buildings are in parallel with the voltage source. Every parallel circuit in a building creates a ground loop unless there is a ground wire that connects all parallel circits in the building. Most older buildings don't have the ground wire connecting the recepticals in parallel. The most dangerous thing I hear musicians talk about is "lifting" grounds in their equipment to prevent ground loop noise. Beleive me, this is dangerous! If you don't beleive me, just read the National Electrical Code. Humbucking pickups takes care of most of the 60HZ hum. Hum can happen in equipment,even if the guitar cord is pulled out of it. If you don't believe this, unplug everything from your amp, and turn the knobs up wide open. Noise or hum usually comes from 60HZ line noise. It can also come from transient line noise, and also EMF Electrom Motive Force, like inductance from a transformer, or magnet. Noise or hum can also come from RF Radio Frequency. The air is full of T.V. radio, police, cell phones and all kinds of stuff. The power companies don't inform people of all their defective equiment either. Grounds are lost on telephone poles and other equipment, old power transformers act up and even burn up. I would not blame your humbucking pickup, as hum can get into equipment even with the guitar cord unplugged. I am wanting to invent a power box musicians can plug into that eleminates a lot of these problems. I know there are all kinds of surge protectors, and power conditioners for computers on the market. I think something needs to be invented to eliminate noise in musician's equipment.

Earnest Bovine · Post by **Earnest Bovine** » 5 Mar 2002 10:19 pm

The 912 is a great sounding pickup but it does pick up hum.
There is nothng you can do about it, other than
1. reorienting your guitar, which often helps a lot.
2. turning off stuff especially TVs and computer CRT monitors. These tend to radiate more to the side than to the front which I speculate is due to testing of radiation levels only in the front where Big Brother (your US Govt) puts their test equipment to protect you, the helpless victim, from an agonizing Hiroshima-style death under the jackbooted heels of your of captitalist oppressors.
3. trying a different pickup.

Bob Hoffnar · Post by **Bob Hoffnar** » 6 Mar 2002 12:44 am

Jon,
I keep a piece of aluminium foil handy that I put under my volume pedal sometimes. It fixes some hum problems.
Another easy fix can be to turn off any neon lights you can get at.

Bob

Ricky Littleton · Post by **Ricky Littleton** » 6 Mar 2002 2:55 am

Jon:

Have had this happen alot. In badly wired places, sometimes the neutral and ground in the power distibution is all hosed up. Sometimes I have used the foil under the volume and otherimes I've had to use a "pig-tail" adapter to take my amp off the building ground. When I was doing amp work, a lot of guys use to cut the ground pin off their amp power cord, BUT NEVER, NEVER, NEVER do that. Keep one of the little 3-to-2 wire adapters in your pac-a-seat or in your amp . Give that a try. Has worked for me on a number of occasions. As the other guys said, those neons and other flourescent light fixtures can drive you crazy!

Just my $.02 worth.

Ricky

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Emmons LeGrande - 8x4
Session 400 Ltd
Alesis Microverb
Dan-Echo, E-Bow

Jon Light (deceased) · Post by **Jon Light (deceased)** » 6 Mar 2002 12:57 pm

All of your ideas, suggestions, and thoughts are greatly appreciated. I'll be back at this bar in three weeks and I'll be prepared to implement each of the potential fixes (tin foil, three-to-two plug converter, moving the guitar around--oh yeah---I forgot to mention a tiny A/B box I built that plugs right into the guitar for silent tuning--it ain't a model of perfect shielding--so I'll pull that out of the signal chain. I sure hope this all will get at the problem. Pickup replacement will be a more radical step--I'm not in the mood for messing around with pickups unless absoltely necessary--the 912 suits me well. I think I'm going to have to call Bill Lawrence (God help me) to see what he thinks. If this is a side effect of his sidewinder pickup then I may need to look for an alternative.

Thanks again.

John Russell · Post by **John Russell** » 6 Mar 2002 2:29 pm

Jon:

I was intrigued to read the suggestion to place foil under the volume pedal. I was changing the pot on my Goodrich pedal the other day and before reattaching the plate on the bottom, I hooked it up to check my soldering work. Lotsa noise! I thought I'd bungled the job, till I reattached the plate on bottom. Quiet as a mouse. That pedal can pick up a lot of noise, depending on the above mentioned circumstances. Makes me wonder how those Ernie Ball pedals manage to function with their open "architecture." Then there's the ol' Fender guitar noise issue, which some techs claim can be eliminated by carefully shielding the innards of the guitar. Wonder if our beloved PSGs need similar shielding?

--JR

Keith Hilton · Post by **Keith Hilton** » 6 Mar 2002 3:06 pm

I wanted to say a little more about grounding. You can buy a test device that will tell you if a receptical you want to plug into is wired correctly. This test device will even tell you if there is a ground wire hooked inside the receptical. The problem is you can't do anything about it if there is something wrong. What you can do is make sure your equipment is grounded correctly. Before you solve a problem you must know what the problem is. The problem is musicians using several powered devices,with each device having it's own individuial power supply. Each device has it's own voltage reference to ground. If voltage reference to ground is different in the devices, then it is easy to see why current could be transfered from one device to the other. This is especially true when the metal case sees this voltage. Thats when you can get transient voltage coming down a guitar cord. Example 1 Guy using 2 old Fender Twin amps that have leaky filter capacitors, and ground plugs have been cut off of power cords. Case of one Fender Twin gets voltage on case and the other Fender Twin has a better ground reference. ZAP--it would be easy then to see as much as 120VAC going down the guitar cord. I have seen this happen! Example 2 Guy gets tired of buying batteries and builds a 9 volt power supply. The case of the power supply is grounded to a ground plug on the power cord. Old amp has ground plug cut off. The amp sees a better and closer ground on the 9 volt power supply and current heads down the guitar cord. I have seen this happen. By the National Electrical code: Anything over 30 volts is dangerous. Anything over .005 amps or 5mA is dangerous. The current in a receptical is usually--120 volts at 20 amps. Besides killing yourself, it is easy to damage equipment if stuff is not grounded properly. Never cut grounds off of power cords.

Jim Smith · Post by **Jim Smith** » 6 Mar 2002 3:39 pm

The reason to keep the ground pin is so that when you do have access to a grounded plug you can use it.

When you use the adapter you're supposed to attach the little tab to the cover plate screw of the outlet to connect to ground. I've never seen anyone do that though, and it may not be grounded either.

Keith Hilton · Post by **Keith Hilton** » 6 Mar 2002 6:26 pm

Jim, you are correct. The thinking behind the little wire you attach to the center screw, that holds the cover plate on, is that the receptical will have a ground wire run to it, or to the metal case it is attached to will have a ground wire attached. Trouble is, there may be no ground wire, and there are many plastic receptical boxes. If there is a ground wire attached to the receptical, or a metal box holding the receptical, then the little screw for the cover plate is a ground point on a old time receptical that doesn't have the 3rd hole.

John Steele (deceased) · Post by **John Steele (deceased)** » 6 Mar 2002 11:39 pm

Seems like a common problem, Jon. I'm guilty of using the 3-2 adapters when there seems no alternative too.
Last week someone told me that if you have more than one thing in your rig plugged in (i.e. your amp and a stomp box) that you should make sure they're all on the same circuit, preferably the same outlet. Any comments on that ?
-John [This message was edited by John Steele on 06 March 2002 at 11:40 PM.]

Ricky Littleton · Post by **Ricky Littleton** » 7 Mar 2002 2:34 am

John:

IMHO I agree with you. Duplex outlets in the same room may not be on the same circuit at all. If the grounds an neutral are all horked-up (not uncommon in un-informed do-it-yourself installations) putting your gear into outlets on different circuits may result in what's called a ground-loop and man you talk about hum, the occasional bite and a general pain in the a$$. Whenever possible, I always make sure I'm plugged into a single circuit. We run into that problem here (Ascension Island) with some of our older facilities. They've been re-wired over the years by countless folks and things aren't always documented like they should and being a government facility, electrical codes aren't always followed so neutral and grounds are forever being crossed up.

A person would also be wise to occasionaly clean and burnish your guitar power cord plug. I do that pretty regularly, mainly when I clean my amp. A real fine sand paper and some good isopropyl alcohol or contact cleaner does a great job.

Ricky

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Emmons LeGrande - 8x4
Session 400 Ltd
Alesis Microverb
Dan-Echo, E-Bow

[This message was edited by Ricky Littleton on 07 March 2002 at 02:37 AM.]

Larry Beck · Post by **Larry Beck** » 7 Mar 2002 5:50 pm

Has anyone had any luck with a noise gate in these types of environments?

Don Olson · Post by **Don Olson** » 11 Mar 2002 7:10 pm

Check out a company called Triplite,I have one of their line conditioner boxes and I never have hums or buzzes.
Zumsteel Forever

Buck Dilly · Post by **Buck Dilly** » 14 Mar 2002 5:17 am

I have a Tripplite LS600. I bought it after I burnt out a $1000, digital rig in a dive in Brooklyn. It is awesome. It will bring a low voltage outlet up to correct voltage for a limited number of Amperes. It also protects from voltage spikes etc. It is a great unit. I no linger use the digital rig. But I find NYC to be the most problematic place on the face of the earth, as far as hum and buzz are concerned.

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Steels and Guitars. Emmons PP, Nationals, Dan-O's, ES 340, Tube Amps only! "Blue Sparks From Hell" and "Kings in Disguise".

Mark Herrick · Post by **Mark Herrick** » 14 Mar 2002 4:53 pm

So Jon, is this a secret back-room bar or are you going to tell us where it is so us locals can come out hear the hum for ourselves...

John Floyd · Post by **John Floyd** » 14 Mar 2002 5:40 pm

Jon
I have a Ground Tester from Eccos Electronics Corp, Model 7100 that will tell me if If the House outlets are wired properly. I believe radio Shack sells a similar device. Mine has 4 neon indicator lamps. Most any Electronics/ Electrical Suppy house usually have these also. Its a good idea to have one on a gig, all you have to do is plug it in the outlet in question read the lights and compare to a table usually on the tester itself. Some only have 3 lamps, the 4th one on mine is a ground impedance check and will flash if the ground impedance is over 2 ohms or will be on steady if under 2 ohms. If I have a hum problem, the first thing I do is plug the tester in and try to eliminate the house wiring as the cause if possible, then I know it is in my rig. These testers are fairly inexpensive and can eliminate some headaches in trying to trouble shoot a problem.

I repeat what the others have said, Never Cut the ground pin from an electrical Plug, Unless you have a death wish and always beware of the 3 to 2 wire adapters these can be dangerous also.

If the House wiring is faulty, I don't know what to tell you. Personally I would walk off the job. But sometimes The Club owner might call in Uncle Guido and that could be more dangerous than bad wiring.

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John - Camden Recording and Sound Services
[This message was edited by John Floyd on 15 March 2002 at 01:30 AM.]

Jon Light (deceased) · Post by **Jon Light (deceased)** » 15 Mar 2002 4:19 pm

Hey Buck! Man, I only aspire to playing in a Brooklyn dive. As of now I am playing in the back room of a Brooklyn dive. When I make my way to the front of a dive it will be time to start puttin' on airs.
I'm intrigued by the Tripp info. Thanks, Buck & Don. And thanks, John for that info & advice. As to diagnostics--well, as soon as I got home I set up just to see, and sure enough, my rig is dead quiet. So there's no mistaking that the problem is pretty fundamental. At this room I did cut out all the effects and unplug the wall-wart----straight from guitar to amp. And the hum follows the volume pedal. So it's in the pickup, I reckon. So number one solution would seem to be moving the guitar around (and foil under pedal---I didn't bypass the pedal during my trouble-shoot session so that remains a possibility.)
Bottom line--I'm back in this place in 3 weeks. I'll try a bunch of stuff and hopefully I'll be able to report some improvement.

Mark--I could tell you where this place is but then I would have to.....blahblahblah.....actually I did post it in 'Announcements'--it's Freddy's in Brooklyn---
http://www.freddysbackroom.com/

---you really know it's a back room when that's what they call the website.
Dave Fudge is the artist. A bunch of his band-mates (he also fronts a rock band) were in the house and they dug it so much that he and they are launching an acoustic offshoot that they want me in on--I couldn't be more flattered.
Anyway, I'll post an announcement for our April 7 gig at an appropriate time.