Ground hum

P

philclcc

Member
Hi,
finally got my axe-fx today and plugged it in, first thing I noticed is a loud hum...

I edited the noise gate settings, increasing the threshold to -50 removed it but when I play the gate opens and the hum is clearly audible, it mostly goes away if I rest my fingers on the strings of my guitar which leads me to two questions..

1- is this a problem with the ground in my guitar?
2- is there a way to change the vate settigs across all presets?

For info i have a musicman silhouette special going into the front of the axe-fx, then unbalanced output 1 into my speakers (embarassing multimedia ones) then headphones out of there. I have a behringer miniamp that people use on here which I will try tomorrow to try and rule out the speakers but I dont think this is the problem. The guitar as a humbucker in the bridge position but the hum can be heard with all three pickups.

Any ideas?
 
try a different guitar... eliminate that problem first.
bad cables?
only on high gain patches? or all the time?
 
I think it might have been a bad cable, just tried with a different one and it seems better, will confirm later when i can spend a bit of time on it
 
OK, it wasn't the cable, I've tried three different cables and they all have the same symptom, I've tried the behringer headphone amp and can still hear the buzzing, I've plugged the axe-fx into my macbook and can hear the buzzing, the only thing that will stop it is touching the strings...

I have noticed that if I have the volume on my guitar at about 9 instead of 10 the buzzing is MUCH louder, not sure what the significance of this is but it's definitely there and on every pick up position (single coil in neck and middle position, humbucker in the bridge).

I'll be playing the guitar through a normal tube amp tomorrow and see what happens there, if there is no buzzing then the logical conclusion is that the problem lies with the axe-fx, correct? I'll also try another guitar through it but don't have any other guitars and there won't be any other electrics round at church tomorrow.

I'm thinking I should probably take my guitar into the local luthier and see what he says...
 
No, that is not necessarily the logical conclusion. There could be something in your environment that your pickup are picking up. It could be a ground loop w/ another piece of equipment after the Axe-fx. If you set up in another environment all these thing could change.

However, if your guitar still does hum in another environment w/ different equipment it would tend to point at your guitar as the most likely issue.

First is when you move you guitar around does the hum change?

Can you try another guitar in the same environment?

Are you using the balanced XLR outs on the Axe-fx, if so have you tried flipping the ground lift switch?
 
The hum changes when I move the guitar towards the axe-fx or towards the power supply, but not if I walk around the room, when testing just now, if the guitar is on full the buzz isn't too bad and is probably manageable but if I turn the volume down on my guitar to about 9.5 the buzz is much louder
 
I have exactly the same problem in a house I moved to recently (I had no problems before).

Your pickups are probably picking up interference from something in or around the room. Things like dimmer circuits, low energy bulbs, and even improperly grounded sewer pipes(!) can cause this kind of interference.

I've tried all sorts of ground lift devices and even tried powering the AxeFX from just a battery powered UPS with everything else in the room switched off and nothing makes any difference. It's a total bitch to troubleshoot and I've resigned myself to just tolerating it until my lease is up and I can move again. Completely sucks - the tails of all the beautiful Axe effects just get buried in hideous crackling hum. :cry:
 
Your guitar acts as an antenna.
My laptop is terrible, it makes buzz my guitar and i can hear the drive working (probably a ground loop). :(
Have to buy a Furman, should help for the ground loop perhaps.
 
Your guitar is picking up interference from something. There is nothing wrong with your guitar. If placing your fingers on the strings stops the noise then you have nothing to worry about. This is why there is a ground wire to the bridge.
 
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