"Dirty" AC from wall outlet?

[Super Locrian]

I just took home a used Fender Pro Jr. Tried it at the seller's place, very quiet. Took it home, and I swear it's much more noisy. I thought my old amp had noise problems and was going to have it serviced, but now I wonder if the real source of the problem is the wall outlet... The noise is a kind of static hiss, it's noticeable but moderate. Is there any noise filtering unit that I could put between the outlet and the amp?

 

[phsyconoodler]

The first thing to do is get a wall socket checker and see if the socket is wired right.They are cheap at Home Depot.Then there is computer monitors,TV sets,Dimmer switches,florescent lights and pole mounted power transformers.
The best starting place is the wall socket and make sure the main power panel is grounded properly.
I have no ground in my house(1947) at all but I find ways to turn and spots in the house that are acceptable for noise.
Also pumping high gain pedals into the amp induces noise.

Oh,and one other thing.While transporting the amp from the sellers house did you happen to lay the amp on it's front or back?If so,you may have loosened up the already rather loose fitting tubes.Make sure they are fully seated.And the ribbon cables inside the chassis need to be away from the rear cover.If not the amp can be hissy.Again,this can hapen during transportation.

 

[OlAndrew]

Not uncommon at all, in fact, if you ever poke a 'scope probe into a wall socket, you ain't gonna see that nice, even sine wave your high-school science text showed you. Some wall power is pretty horrifying, when you actually get a look at it. Might want to have a look at data-grade power conditioners, if that's your problem.

 

[mrface2112]

Dimmer switches.

Dimmer switches are the killers. They'll nasty up a circuit in no time flat. If you have dimmers for your lights, pull em out. I've even heard of them causing dirty power throughout the entire house (dimmer in the living room, amp in the basement). Fluorescent lights are nasty too.

Could also just be that you've got dirty power coming out of the wall. Are you near any factories or industrial areas? or high voltage wires or transformers? are you in an apartment or a house? what about neighbors--do you have any and if so, how close?

You can certainly check into power filtering and regulation. I probably would. I'd probably get some filtering for my TV and any other piece of electronics i wanted to live a long life, too. but beware--good ac regulation isn't cheap. and a lot of the cheaper stuff out there is nothing more than an overpriced power strip.

I deal with this problem whenever i play at a friend's apartment. His AC isn't as clean as mine is (out here in the sticks), so my amps always get buzzy over there. sometimes i can mitigate that through outlet selection and amp location.

Keep us posted and Good Luck!

cheers,
wade

 

[cap47]

It is best to wire a dedicated socket back to the main panel making sure the wide receptacle side is connected to white, narrow receptacle wired with black wire and the bare copper to rounded receptacle at wall plug. White and copper to a buss bar and black to the breaker 20A circuit in the panel box!

 

[chervokas]

Actually, IIRC, there were known issues with noise with the Pro Junior as originally designed both in the wire dress and a mounting screw on the back panel that contacted the chassis or some piece of internal sheilding and created a ground loop. I think Fender fixed the screw issue in later versions and the most recently released mk. III is supposed to feature improved sheilding and better wire dressing to reduce the noise.

It could be line noise in your house of course. But the Pro Junior always had a reputation for being a little noisy.

 

[Soul Man]

Bringing this back from the dead.

The last two amps I have brought home (one new out of the box) sounded great at my local shop but then at home, crackle, hiss and pop at various times after plugging in.

It has to be my outlet "noise" in my music room because one bad amp is possible but multiple times? So that said.........

Re-wiring the room (or the house, LOL) isn't an option so what products are out there that I can use (good quality power strip?) that will help me clean up the fizz that comes from the outlet?

Thanks!

 

[Soul Man]

Anyone use one of these:

http://www.sweetwater.com/store/det...mx&adpos=1t3&gclid=CLPjkK3Iu6wCFRAj7AodBw4yoA

 

[DavidH]

Nah, those filter thingies tend to do sweet FA in my experience. Your amp's power supply has better filtering already one would hope. If you're really looking to clean up the incoming power, a 1:1 isolation transformer type deal is what you need to give you smooth AC.

 

[DavidH]

Cool. I'm suprised that worked. The amp should sound better with lower noise floor. The noise on the line is probably on the mains long before it reaches your house, so it's devices like these or a power conditioner to solve it. Some amps do better than others at my place, depending on how well designed they are, and how noisy the individual power transformer is, they seem to vary from one to another in how much they rattle.

 

[guitkrazy]

I would definately use a power conditioner. It is amazing how much dirty power (or unstable power) is in a home or even clubs.

 

[DavidH]

I think, but i'm no engineer so don't quote me on this, that the high end hiss is RFI, and the 'hum' is more to do with DC on the line causing the PT windings to rattle (where isolation transformers help by smoothing the supply to pure AC). Maybe you have RFI hiss at your place so that's where the filter is helping. It's something i need to look at in my little studio but since we're moving next year i guess i'll wait and see, i need some kind of power conditioning solution for the whole room i think.

 

[donnyjaguar]

Don't forget all those new Compact Fluorescents have switchers in 'em!

 

[Soul Man]

O.k., I'm still trying to get some line noise cleaned up. The more I read and the more I research, the more confusing it gets!


The thing that confuses me is the difference between a voltage regulator and a power conditioner. In some places they are described as the same thing but in others they are defined differently.

My #1 goal is to limit line noise through my amp. On top of that, I certainly would like to protect it (or other items in my house) from goofy power.

My outlet is wired properly and I don't have any dimmers, etc., it's just noisy.

Here are a couple products I am looking at now. Very different indeed and in some ways they seem similar but..........different.

Any thoughts on these? I admit, I'm confused, LOL.

http://www.amazon.com/APC-LE1200-Automatic-Voltage-Regulator/dp/B00009RA60/ref=cm_cr_pr_product_top

http://www.amazon.com/Monster-Cable...tector/dp/B000NJGRH8/ref=cm_cr_pr_product_top

 

[killer blues]

I just took home a used Fender Pro Jr. Tried it at the seller's place, very quiet. Took it home, and I swear it's much more noisy. I thought my old amp had noise problems and was going to have it serviced, but now I wonder if the real source of the problem is the wall outlet... The noise is a kind of static hiss, it's noticeable but moderate. Is there any noise filtering unit that I could put between the outlet and the amp?

you need to wire an isolated ground recepticle with its own dedicated feed directly to your electrical panel. This will eliminate any noise induced by other circuits as well as insuring a proper ground. the recepticle is orange in color and is code now in some jurisdictions for computers and home et systems. All those other inline conditioners are wortheless and a waste of money.

 

[lchender]

You could also look at some of the Furman professional grade power conditioners. They're expensive, but are supposed to be great at taking nasty, dirty power and churning out nice, clean power to your rig.

You might want to check how expensive it is to pursue some rewiring at your house, though. It's entirely possible that it would be a cheaper solution (although you could take a Furman power conditioner with you to any gig and be assured you'll have clean power going to your rig).

 

[Miami Mike]

This is a huge subject. Dirty power is very common, every computer, dimmer,florescent light distorts the wave form. Line reactors ( tuned coil/inductors ) are the industry standard for this issue. If what you buy has no coils it probably won't really work.
Capacitors can adjust for current lag. The problem with these items is every dirty power situation is different depending on what is making it.
I like Old Tele Mans idea of this type http://www.corcom.com/pdf/MV.pdf because the schematic shows it uses inductance. The problem is you have to build an enclosure for them that plugs in.

 

[TwoTubMan]

I average 144 volts, mainly because the "box" is in my back yard. I'm first in line. I go through lightbulbs like you wouldn't believe.

My tube amps do not like it.

Power company is useless. They claim no problem.

 

[roadhog96]

...when I encounter noise, I use a CORCOM "hospital" EMI power-line filter assembly.

...works great.

Which model do you use?