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Amp hum...

W

WayneS

Apr 9, 2007
873
10
Virginia
#1
I searched but could'nt find the answer.

What is a common cause of loud humming that goes away when the guitar volume is turned down?

The electronics are grounded and the amp is as well. When you touch the strings the humming stops also. I know its a grounding issue but I cant find it. And the funny thing is that I'm an electronics technician.

Thanks!
 
#5
Sounds like the 60 (hertz or something of that variety) it is notorious and probably won't go away. A good power conditioner may help, maybe. But, that is just a shot in the dark. There are sooo many variables it tough to say w/o knowing exactly what you are using.
 
#6
WayneS said:
In side of the electronics cavity in the bass (or guitar)?

Patience please, I know nothing about this stuff.
Click to expand...
Yes, in the cavity. Most are lined with aluminum paint or tape to reject spurious signals. However, I did have a set of pickups that hummed no matter how much grounding or shielding I used, and the only option was to replace them.
 
#7
G00D+~VIBES said:
Sounds like the 60 (hertz or something of that variety) it is notorious and probably won't go away. A good power conditioner may help, maybe. But, that is just a shot in the dark. There are sooo many variables it tough to say w/o knowing exactly what you are using.
Click to expand...

Well... I'm using a Fender P through a Fender BXR200 practice amp.

But, the guitarist has the same problem. Could it also be building ground perhaps?
 
#9
This most likely sounds like a grounding problem on the instrument.
"... It buzzes, until i touch the strings..."
Its possible there may not even be a ground wire coming from the brige in the circuit..
This could be one reason why.
 
#10
WayneS said:
Well... I'm using a Fender P through a Fender BXR200 practice amp.

But, the guitarist has the same problem. Could it also be building ground perhaps?
Click to expand...

It might be a bad house ground. I've run into that problem at a few places I've played at over the years. Other than that, your P-Bass if it's of the common variety with the split coil pickup, it should be wired up to be humbucking, and there should be a ground wire under the bridge plate. Jimmy M asked you the best question of all. How does your rig sound somewhere else?
 
#14
OK, there has been a couple good things to check here.

My guess is the bridge to electronics ground in the bass is broken or missing. However, I'd run down to Home Depot or some place like that and buy an outlet checker, they are about $12 bucks. It will tell you if you outlets have a grounding issue.

Here's something else. With the amp humming away turn yourself left and right and see if the humming NULLS in a couple spots.

In my dining room I have the main house power running under the floor in non-metalic tube. The JAZZ picks up this strong magnetic field. When I had the 7000 watt amp sitting in the dining room this was a really loud problem until I turned 90 degrees and it nulled... I now have the big amp in the living room much to the old lady's chagrin.

The problem is the bass or effects picked up by the bass.

BOB
 
#16
WayneS said:
But, the guitarist has the same problem. Could it also be building ground perhaps?
Click to expand...

Likely environmental - are there flourescent lights, computer monitors or other noisy devices in the practice area? If you suspect faulty wiring, pick up one of these. They're a good thing to keep in your gig bag if you tend to play in spaces where there may be wiring that's not to code.
 
#17
rbonner, you might be on to something. I just recently had my basement finished. Ever since i started playing down there is when i noticed this problem. I will run out to home depot like you suggested and test the outlet. I am crossing my fingers that this is the problem.
 

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