Humming, Ground Issue?

[Cody Coombs]

Recently I’ve noticed while playing through headphones my Mullen Royal Precision will have quite a hum with the volume pedal at full. It doesn’t hum when I have the volume pedal closed, and when I touch the strings with my finger picks close to the pickups the hum will go away. It seems to have a slight hum on the C6 neck, nothing bad. Except the E9 neck is where it really is there.

I haven’t noticed it before until recently, is this normal for the single coils in it? I’ve done some reading on previous posts, but haven’t come across this specific issue.


Could it be that my ground wire is loose, pickups are going bad, perhaps it was always there and never noticed it until now and it’s normal?


Any advice or information would be helpful!

Thanks in advance,
Cody

[Donny Hinson]

I'd guess either your power source (outlet or power cord) isn't properly grounded, or your changer is not grounded to the guitar jack/endplate.

[Cody Coombs]

Is this the ground wire you are referring to?

[Larry Bressington]

It's probably normal AC hum if you are in a house? As a test, move the steel at an angle of 90 degree's and see if it diminishes some, single coils are very buzzy in houses, something to do with a house ground loop.

Try some different leads too, and make sure they are not running over an extension lead or power outlet, as electricity is magnetism it does attract. Check the source you are using for an amp to see if it's at the input jack, maybe dirty etc etc.

[John Hyland]

If you have a multi meter check the resistance from the finger roller at string to the sleeve of your cable. If that is ok then probably your guitar isn’t the issue.

[Donny Hinson]

Cody, that looks like the guitar jack. Try loosening that jack, rotating it 1/4 turn, and then re-tightening it.

[Cody Coombs]

I don’t notice it with an amp, just had practice tonight with the band and it was quiet as a mouse like it should be! Only hums through my headphones in my little practice room. I do Know I recently added a space heater to the room that’s always on when I’m practicing. It’s a very small room. Perhaps that’s too much power flowing in the same room? I’ll do a little troubleshooting and checking all your ideas you guys have mentioned.

[Ron Pruter]

It appears grounded to the end plate correctly. (Via jack) Also touching it and it gets quiet, is just what it should do. I recommend what Larry B said, "angling it around". When I record, there is always a sweet spot. Ron

[Cody Coombs]

Well it turns out that a few of my pedals might be a little too hot to run direct into my silent practice setup. If I just run straight steel, volume pedal and a couple smaller pedals I don’t hear it at all! When it’s time to play through an amp all is good with my normal setup. I recently added a wampler Hotwired and a wampler compressor so I believe those are the culprits when I back step through my pedals.

Thank you everybody for your help and advice

Cody

[George Kimery]

Are the single coil pickups close to the amp? Try an Electro-Harmonix Hum De-bugger as a last resort. It has always solved my grounding issues.

[Dave Grafe]

I do Know I recently added a space heater to the room that’s always on when I’m practicing. It’s a very small room.

The coiled wire elements in electric heaters are by definition as efficient an AC hum generator as could be devised, and your single coil pickup is an equally efficient receiver of the same.

If the noise began with the introduction of the space heater that would be the obvious culprit.

Now you know.

[John Drury]

Dimmer switches will do that as well, or fluorescent lights in the house or in the average Skull Orchard.

[Bobby D. Jones]

If it only happens when you use Head Phones. Check the Plug and wiring on the head phones.

If you have a tuner and effects pedals in the circuit. Take them out of the circuit and put them back 1 at a time.

[Jim Sliff]

I'd guess either your power source (outlet or power cord) isn't properly grounded, or your changer is not grounded to the guitar jack/endplate.

Yep.

Or an inexpensive cable.

What are you plugged into?

ALWAYS start with the wall outlet using a $7 outlet checker. This should be a policy every place you play. Many, many outlets have a 3-prong plate but no ground, or it's improperly grounded...or the hot and neutral are reversed, making you the ground. Not good. This requires a licensed electrician.

When I moved into my current house it cost me $5k to correct the wiring and install a 200amp breaker box.

Then find out what is connected to the same circuit breaker. Motorized appliances (even when off) liken refrigerator, AC units, central heating ...

fluorescent lights (even small twisted-shape bulbs), TV's, computers - unplug each one and play.

Then change the direction you sit in relation to the amp. 90-degrees is usually OK, but facing or very close to it no matter what the angle is not.

Toss out $15-20 power strips and use a voltage regulator type - roughly $80-120 but can kill hum and protect you.

Then switch guitar cables; then test it with a different amp.

Last - try different headphones.

But don't skip steps. 55 years of electronics and guitar tech work has proven this method over and over. You always work your way TO the headphones. Not the reverse.

If it's the same throughout that process of elimination, you have narrowed it down to a non or badly potted pickup or bad string ground. but if it stops at any other step, you've saved a lot of time.

[Cody Coombs]

Well I’m in my fifth wheel trailer what keeps me close to work, so the wiring in it isn’t up to standard house wiring I wouldn’t imagine. But here’s how my setup looks like when I do silent practice - pedal steel, volume pedal, effects pedals (boss tuner, wampler compression, wampler Hotwired, milkman delay, boss reverb) all in that order into my small Yamaha MG06X mixer. Then headphones out to hear it all and not disturb or serenade the neighbors!

I will certainly try moving to a different spot in the room, and try what you have mentioned. I don’t notice it when I run just a delay pedal and use the reverb off of the mixer. I will back step through the whole setup to find the culprit.

I do run my iPad or computer into one of the channels to play along with songs, could the fact of them being in the same room (very small room) affect anything?

I have tried playing without the space heater even plugged in or in the room and still have the hum. What’s strange is when I touch the strings with my metal picks sometimes even the tonebar the sound goes away and is a clean sound. Makes it kind of hard to do open string licks or a boogie woogie blues thing. Hmmm.

And again, the hum Doesn’t exist when I run through my peavey amp.

Maybe the mixer has something to do with it?

[John Hyland]

If touching the string makes the hum go away your guitar is not grounded properly. It is possible for the end plate to be grounded as proven by your tests? But the bridge and strings may not be. The bride needs a groundignwire to the end plate/output jack

[Bengt Erlandsen]

Are the pedals you are using running on battery or do they share the same powersupply that has individual powercables to each pedal ?

If they are powered from a powersupply you might have one or more ground loops that picks up electrical noise. The powersupply for pedals and the power to the mixer might also create a GND loop that picks up hum.

To fault isolate, try running guitar directly to mixer with a single cable and check if the hum disappear.
Guitar->Cable->mixer->headphone

If still hum, dissconnect anything else that runs on the same poweroutlet as the mixer use or try a different poweroutlet for the mixer.

The more electrical equipment one use(pedals, rackmounts, powersupplies,amps,mixers), the easier it is to create unwanted ground-loops and those ground-loops can be quite tricky to trace down and fix in order to have only "one" common ground running through the setup.


The two solderjoints on the jack on the guitar I would redo. Unsolder, clean and re-solder. They dont look as good as they should be. Measure with an Ohm-meter from the string to the ground of the jackplug and there should be close to zero ohms. The closer to zero the better.

Best of luck finding what cause the hum.

B.Erlandsen