Can't get rid of hum/buzz!

[thebigcheese]

I upgraded to an Orange TH30H not too long ago (and posted my thoughts about it here), but I noticed there was some hum/buzz (both, really) coming out through the speaker. At first, I thought maybe it was something with the amp, so I emailed one of the Orange techs who took me through a couple troubleshooting steps. None of those solved the problem, so I thought I'd just try plugging it in on a different circuit just to see what happens. That cleared it right up, so I figured I would try a power conditioner. First I bought the Furman power strip (not a rackmount unit), but that didn't help. I bought the Monster Pro 800 power strip, which didn't do anything, so then I exchanged it for a Monster Pro 1000, which also did nothing. Well, the amp did sound a little clearer, but the hum/buzz didn't change. So I tried the Ebtech Hum-X. Still nothing. What gives?

The obvious solution would be to move it back to that other outlet, but that's really not an option. Unfortunately, all my recording gear (and music gear) has to be in the same room, which is also the same room as my home theater system. Am I just stuck with it, or have I just picked all the wrong things?

 

[TetraFish]

Just teach the amp the lyrics and it wont have to hum....Sorry, it's early and I'm tired.

Seriously though, is there anything else on that circuit that has a rotating motor, like a fan, or a fridge?

Does it do it with and without a guitar hooked up? For some odd reason my guitar will cause a hum if I'm I'm facing my computer and am within close proximity.

 

[thebigcheese]

Mine does that too, but the amp will do it even with the guitar turned all the way down. Doesn't do it in standby, though. And there is a computer, PS3, Xbox 360, LCD TV, and surround receiver all on the same circuit. Unfortunately, I can't move any of those things elsewhere and I can't move my studio, either. Well, I could move the amp and computer if I really had to, but I can't move the drums, so it would be really inconvenient to have to move the computer every time. I guess I could get some pads and just use EZ Drummer, but I spent a lot of money on nice drum mics...

 

[miroslav]

...so I thought I'd just try plugging it in on a different circuit just to see what happens. That cleared it right up...

You already solved your problem...it's the AC line. Use the one that cleared it right up.
Something on the other line is causing the problem that you are trying to fix. Power conditioners don't remove everything/anything...you have to find/remove the cause on the funky AC line if you want to use that circuit.

 

[JCH]

You already solved your problem...it's the AC line. Use the one that cleared it right up.
Something on the other line is causing the problem that you are trying to fix. Power conditioners don't remove everything/anything...you have to find/remove the cause on the funky AC line if you want to use that circuit.

Not necessarily. It might be an RF problem in the location of the outlet where he wants to plug in.

Try lifting up the amp and rotating it around. Does the hum change?

 

[thebigcheese]

Nope. I've also tried other outlets on the floor (I'm in the basement), but no dice. The problem is that I can't move it to the other outlet that worked fine. I'm still living in my mom's house, which means that the basement is designated for all my stuff and the home theater system. I was really hoping there would be SOMEthing I could do...

 

[Zaphod B]

Same circuit as a computer, right? Fan running on the computer all the time? Electric motors are notorious for introducing noise in an AC circuit.

 

[gregsk777]

I had a similar problem and tried everything but nothing helped. My Fender Showman and any guitar with p90's or single coils buzzed like crazy. No gadget helped what so ever.

I then got a cheapo practice space in an industrial storage facility and now have 0 hum/buzz, even on p90's. So it all has to do with proper grounding and wiring of your house.

Also try a new power cord. I had a Marshall that buzzed until I replaced the $5 power cord?

 

[thebigcheese]

Same circuit as a computer, right? Fan running on the computer all the time? Electric motors are notorious for introducing noise in an AC circuit.

See, that's the other problem. Even if I move everything, it's all still going to be on the same circuit as the computer. Do studios just have different circuits for every outlet?

It's really only a problem with the guitar amp, which is the worst part. I do bass direct and the drums obviously don't hum. I guess I could move the amp upstairs and buy a 100-ft mic cable or something. That'd be a real pain trying to run that and some headphones and a transport control up there, though. I could always just use Amplitube, but I really like the sound of my amp...

And a practice space would cost a lot of money, not to mention I'd have to go there every time I want to record, so I'd have to bring everything with every time. Nooo thanks.

 

[miroslav]

It's not a lot of work and not very expensive....run a clean, 20Amp line from the main circuit breaker box to your basement location (I bet the circuit breaker is down in the basement too…and not too far away).

You can run the wire yourself (12 gauge will be right for 20Amp service), and just get an electrician to do the final hook-up at the circuit breaker. A clean line with its own breaker, dedicated to your audio, will take care of a lot of AC issues.
I have (3) 20Amp lines for my studio...but one is more than enough for the more typical home studio setup. It's no more difficult to run the heavier, 20Amp line than a lighter 15Amp line...but that way you’ll have room for expansion later on.
Cost for the wire, outlet, breaker...less than $50. An electrician shouldn't charge a whole lot to make the hook up for you.

I did all my own...but I've done electric work before and know my way around. DON'T DO IT YOURSELF---it can kill you if you don't know what you are doing.
Once you run the clean line…put your power conditioner on the end of it and plug your gear into that. You should have some nice clean AC.

 

[thebigcheese]

It's not a lot of work and not very expensive....run a clean, 20Amp line from the main circuit breaker box to your basement location (I bet the circuit breaker is down in the basement too…and not too far away).
DON'T DO IT YOURSELF---it can kill you if you don't know what you are doing.
Once you run the clean line…put your power conditioner on the end of it and plug your gear into that. You should have some nice clean AC.

I would never try it myself. The circuit breaker is in the same room, actually, and the amp and the computer are on different outlets. Actually, I could really just have an electrician move the one outlet to its own circuit. I might have to look into that.

What you may want to try is turning off everything in that room, but the amp, including the lighting and see if the noise still exists. Unplug stuff that can be unplugged. If the noise still is there after that room is dead, go to an adjacent room and do the same. If you've killed the noise, but not sure what did it, start turning things on one by one until it returns. If you can identify what's causing the noise, it may be easier to get rid of it. Fluorescent lights including CFL's can produce some nasty noise in an amp that has high gain, but once you go to another room it will likely clear up.

How old is the house your in?

It's not all that old--probably 50 years or less. The circuit breaker is almost brand new and they put in an additional ground wire for it to bring it up to current standards. There are CFLs here, but they're on a different circuit. The noise level seems to be the same with the home theater (everything) unplugged, though the computer and the wifi router are still plugged in. It was cleaner upstairs, though, so I will have to try that again just to make sure.

 

[gregsk777]

I am not sure if anyone already brought this up, but do you have any other amps and do they also hum?

Who knows, maybe the polarity of all the outlets in your house are wired backwards?

Maybe just yank off the ground prong on the power cord and see it that does it

 

[ggunn]

The first thing I'd do is run an extension cord from the "clean" circuit into the room where you have the problem and see if it still makes a difference. It may have more to do with the level of RF in the room than with the circuit you are plugged into.

This business about "clean" and "dirty" circuits is overrated. All your circuits are connected back at the utility service panel and there's nothing separating them from each other but circuit breakers. Circuit breakers don't have any magic filtering ability; they are just switches. The same with grounding; the neutral and ground conductors are bonded together at the service panel and connected to a grounding electrode. If the wiring is done to code there really should not be an issue.

There may be an issue between two 120V circuits if one is drawn from one leg of the 240V supply and one is from the other and you have gear that is plugged into both of them. The ripple voltage in the DC power supplies (all audio gear has them and ripple is impossible to completely eliminate) is out of phase and in this case can be additive.

 

[miroslav]

All your circuits are connected back at the utility service panel and there's nothing separating them from each other but circuit breakers. Circuit breakers don't have any magic filtering ability; they are just switches. The same with grounding; the neutral and ground conductors are bonded together at the service panel and connected to a grounding electrode. If the wiring is done to code there really should not be an issue.

True...but a separate line to the circuit breaker will still be cleaner than one that has the refrigerator, microwave and toaster on it. The closer your gear to the offensive devices the worse it is.
Also...if you have service with two hot legs, it can make a difference which of the two you put your gear circuit breakers on, depending on what else is on that leg VS the other leg. All my studio lines are on the same leg.
Another possible problem with using other lines is that something as small as a loose connection at a wall outlet can cause pops/clicks because there is small arcing going on, especially the kinds where you don't screw the wires on, but rather you just push the end into the hole and there is a small clip that grips it. I hate those and I went through my entire house screwing down the leads to all the outlets and checking that the Hot an Neutral where correctly wired, and grounds where on properly.

I've run separate lines in a couple of other places/buildings in the past where I had my audio gear…and it helps.
Mind you...if you’re in a real "dirty power" area/building...nothing may help much, but with audio gear, it's always about small improvements that add up rather than one magic step.
Though sometimes it is just one move that can make all the difference.

 

[thebigcheese]

The first thing I'd do is run an extension cord from the "clean" circuit into the room where you have the problem and see if it still makes a difference. It may have more to do with the level of RF in the room than with the circuit you are plugged into.

This business about "clean" and "dirty" circuits is overrated. All your circuits are connected back at the utility service panel and there's nothing separating them from each other but circuit breakers. Circuit breakers don't have any magic filtering ability; they are just switches. The same with grounding; the neutral and ground conductors are bonded together at the service panel and connected to a grounding electrode. If the wiring is done to code there really should not be an issue.

There may be an issue between two 120V circuits if one is drawn from one leg of the 240V supply and one is from the other and you have gear that is plugged into both of them. The ripple voltage in the DC power supplies (all audio gear has them and ripple is impossible to completely eliminate) is out of phase and in this case can be additive.

Ok, I have just run an extension cord (well, two, really) from the "clean" circuit I tested with before and the amp is now dead quiet. So I guess I can just do that whenever I want to record, or figure out a more convenient solution.

 

[musicaa]

when the grounding problem is the grounding itself... (?!?!?)

Hi

I am having a very similar problem also.. so similar that i didn't feel it justified opening a new thread, but i do have some different specifics and ensuing issues.. and some mysteries that reach beyond my understanding of electricity.

I have a small recording setup which I JUST started putting together.. nothing fancy at all, 3 keyboards, a mixer, a fast-track pro & a macbook laptop.

I have not yet gathered the funds for monitors, so for the time being, I am using the speakers of my home theater system, which are being powered by a yamaha rx-v492 AV receiver unit.

I'm having a buzz problem. to which the only solution i have found so far, to eliminate the buzz, is to REMOVE the ground from the power bar which supplies the keyboards & mixer. I do this with a tiny little adapter which takes a grounded 3-prong cord on one end & has only 2 prongs on the other side.

The mixer is sending the control room outs to the AV receiver. (the main out is going to the fast-track pro for recording.) The AV receiver is plugged into another outlet altogether.

I have isolated the problem to the 2 keyboards which are supplied by 3-prong power cords. (the 3rd takes a 2-prong power cord.) When i unplug those 2 keyboards, the buzz stops. When i disconnect those 2 keyboards from the mixer's inputs, the buzz stops.. The problem exists whether the keyboards are turned off or on, all it takes is for one of them to be plugged in, & the AV receiver to be turned on & switched to the right input setting (where the control room outs are going) & it's BUZZ CITY..

I tried different outlets to make sure the power bar is on a different breaker than the AV receiver, but the problem persists.

My main concern is the following:
Isn't it unsafe for my equipment to be operating while the ground has been removed?

Here's an interesting side-plot: my power bar has 2 small lights on it indicating if it's (1) "protected".. & (2) "grounded". BOTH LIGHTS are on! even though i just removed the ground from the power cord! how could the power bar claim to be "grounded" when i just personally physically removed it??

I am confused... any insight?

Thanks!

A

 

[bdenton]

After you've done the obvious troubleshooting, check your phone.

It probably has buttons on in; punch a few of them and call an electrician.

The original poster mentioned the age of his house...do you realize how much a bunch of "weekend electricians" can f*ck up over 50 years?

In my previous house I added some soundproofing to a room that I was using for various musical activities. I was adding some outlets and extensions to some of the existing electrical boxes, so I had the electricians check the four existing outlets in the room.

All but one had some type of problem. Weird circuits, bad grounds, lots of fun stuff. Another $200 to fix it all, but I ended up with very clean power...

 

[ggunn]

.

I tried different outlets to make sure the power bar is on a different breaker than the AV receiver, but the problem persists.

My main concern is the following:
Isn't it unsafe for my equipment to be operating while the ground has been removed?

Here's an interesting side-plot: my power bar has 2 small lights on it indicating if it's (1) "protected".. & (2) "grounded". BOTH LIGHTS are on! even though i just removed the ground from the power cord! how could the power bar claim to be "grounded" when i just personally physically removed it??

What you have is a ground loop and the lights confirm it. The power strip is "seeing" ground through the shield of the connected components.

Ground loops can be a real problem; they occur when a piece of gear has two connections to ground with different impedances. The third prong of a component is one connection to ground, and the shield of the connecting cable which connects the chassis of one component to that of the other and therefore to the other component's third prong is the other connection to ground.

There is no simple and safe way to get rid of a ground loop; lifting the ground (disconnecting the third prong) of all but one of the components is one solution, but it can be dangerous. Converting to balanced connections and clipping the shield wire at one end is another and is more safe.

Connecting all your components to one outlet and keeping the interconnecting cables short can help.

 

[thebigcheese]

I've done it with my computer off as well, still the same problem. I know all the outlets are wired correctly because we replaced them all not too long ago and I personally used an outlet checker on every single outlet. I can check to see if some wires are still loose or something. There's obviously something weird here.

 

[musicaa]

What you have is a ground loop and the lights confirm it. The power strip is "seeing" ground through the shield of the connected components.

Ground loops can be a real problem; they occur when a piece of gear has two connections to ground with different impedances. The third prong of a component is one connection to ground, and the shield of the connecting cable which connects the chassis of one component to that of the other and therefore to the other component's third prong is the other connection to ground.

There is no simple and safe way to get rid of a ground loop; lifting the ground (disconnecting the third prong) of all but one of the components is one solution, but it can be dangerous. Converting to balanced connections and clipping the shield wire at one end is another and is more safe.

Connecting all your components to one outlet and keeping the interconnecting cables short can help.

thanks for the reply ggun.. yea ground loop seems to be the culprit, unanimously..

but you say "all but one of the components".... i have found that the buzz only disappears when i remove the ground of ALL of the components (the entire power bar)
with the ground lifted, the "grounded" light on the power bar comes back on soon as anything with 3 prongs is plugged into it. either one of the keyboards make it come on clear & bright, less bright with the mixer & even less with my keyboard amp.. but they all (each) cause it to light back up, to a greater or lesser extent, thus proving the existence of the ground loop.

i think there is a problem with the grounding in my house.. i've noticed before that when i plug things in, sometimes the outlet makes a small spark. i didn't think much of it before, but i don't think it used to be like that & i don't think it's supposed to. so quite possibly, the house's connection to ground seems to have perhaps "come undone", if such a thing is possible.....

the house was built in 1987, so it's not because it's old. but i think perhaps it's not "AS GROUNDED" as it's supposed to be.... is this possible?

is it possible for a house to be grounded, but not very well grounded..? for the connection to ground to have degenerated or "come undone"?

if i have an electrician friend come over, would it be a complicated job to check/reinforce the connection to ground for my house? isn't it as simple as tying a wire to a water pipe or something?