D@mned amp hum! How do i get rid of it?

[octoruss]

I just refinished my basement studio, with all new walls, ceiling, electrical work and carpet. I was so excited to plug in my Fender amp and play a few power chords when I turned the power on and......"mmmmmmmmmmmmmmmmmmmm"

That loud, annoying amp hum, with nothing plugged in, only the power on.

I tried everything--different outlets, a $40 monster guitar cable, and the best i could get was turning off all the lights in the basement (which are all on dimmers BTW) and plugging into one outlet on the other side of the room that seemed to have less hum than all the others.

How, oh how, can I fix this? Ironically I had a dispute with my electrician over the labor charges and he won't be coming back, so I'm hoping someone out there may have some good advice.

[whattaguy]

Which Fender amp do you have? Is it a tube amp or solid state? I have a Custom Vibrolux Reverb, and it has a hum that that is characteristic of the amp. To quiet the hum, I changed out some of the tubes. The hum isn't totally gone, but it's quieter. I also grew to love the hum.

[octoruss]

Hi Fednerguy,
It's a solid state amp, no tubes. But it's definitely not an amp characteristic, since it has worked fine before...nice and clean. Any electrical engineers out there?

[whattaguy]

Does your amp have a ground-lift switch?

[octoruss]

Actually I don't know...I don't think so...what is a ground-lift switch?

[whattaguy]

It's a switch that breaks up any ground-loop hum caused by other electrical devices in the room...an engineer will probably give you a more technical answer. But, essentially, I think that is what it does. If your amp has one, it should be somewhere on the front of the amp.

[Chill]

Are your basement stuido outlets properly grounded?

[juststartingout]

Yes, check the ground wires. I actually had to put a stake in the ground and run a new ground wire for my studio. It settled everything down. Hum is usually grounding problems. Weather it is electrical boxes or a chord, 99% of the time it is a grounding issue.

[octoruss]

Ok, dumb question, but how do I do that? The outlets are in the wall, and run to the junction box in the basement. If I had to run a cable to a stake in the ground, where would you attach the cable (without getting electrocuted?)

[lysis]

well . . . you would turn off your electricity and then run it. i would run it from the ground on the main power for the room.

[Tulago]

Before you do anything, take you amp out of your basement studio and plug it into a 110 volt outlet you know is clean and grounded (and isolated from other inputs into that circuit). If the amp stills hums, the problem is in your amp.

Otherwise....Dimmer switches are very noisey. Even though your amp is plugged into a different 110 volt outlet, that outlet will be as noisey as the circuit is to the main breaker box.

Try connecting the ground off of the breaker for your basement studio to a plumbing pipe nearby. Or, if that fails you need an isolated circuit that is well grounded just for your amp.

[arcaxis]

Have you tried the amp in another room or house and not had hum ? When the hum occurs is the gain up on the amp or pretty much at 0 ?

Dimmers on lights will cause hum or a buzzy noise. When you turned them off
were they switched off or just turned all the way down ? Flouescents can create noise as well. Lava lamps on the other hand are quiet and soothing....

Is there any other equipment in the room that's on. Something with a large power transformer could induce hum into your amp if it's close by.

There is a small tester you can purchase (see link below), that will check your outlets. It basically plugs into the outlet and depending on what combination of lights come on it will let you know if the outlet is wired correct or faulty. If you are in Europe, I'm not sure about outlet grounding as I think they may be 2 prong versus 3 prong (hot, neutral, ground) in the US. The tester will not check how effective the grounding is of your house to the electric companies system which is done with ground rods driven outside your house. Hopefully your not getting any shocks from your amp.

http://www.radioshack.com/product.as...duct_id=22-141

[juststartingout]

Originally Posted by octoruss

Ok, dumb question, but how do I do that? The outlets are in the wall, and run to the junction box in the basement. If I had to run a cable to a stake in the ground, where would you attach the cable (without getting electrocuted?)

It's easy to test. Pound a metal stake into the ground and run a wire to the back of the amp and screw it to the chassis. If that cures it then run a permenant wire to your fuse box.

[something cool]

Just run an extension cord from the living room, that should take care of it.

[jt93]

amp humming? teach it the words... thank you, ill be here all week..

there are line conditioners you can get also. take the hum, sag and spike out (or so they say)..

[punkin]

We don't yet know all your basement remodelling conditions but be careful with the extra ground post....if you're running off a sub-panel to feed the basement, you really shouldn't have a second/seperate ground source. If the ground rod at your primary utility feed is inadequate, it can be augmented to provide a better ground but, secondary utility panels shouldn't have seperate grounds unless they're completely isolated from the feed source. This is can be a serious safety problem.

If you already have this covered..., ummm...never mind.

[biotek]

this is your best bet.. either that, or switching the phase of your outlets that's you're pluged into... because if it is a problem with the dimmer switch, it won't just be the amp that has problems... you'll get that problem with virtually anything that you plug in... getting an electrician who knows what to do in a studio situation is KEY when doing construction.. and if he doesn't know.. make sure you tell him that you want your equipment on a seprate phase from the lighting..