House Ac line noise

General discussion area for tube amps.

Moderators: pompeiisneaks, Colossal

User avatar
M Fowler
Posts: 14036
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

House Ac line noise

Post by M Fowler »

So I have been trying to figure out if the aweful AC line noise in my home is from my house or outside caused.

However, in the mean time can I simply use an isolation transformer on my work bench to squash this harsh noise? Any suggestions for a good filtering unit?

It appears in every amp I own which never had a problem with line noise before.

In the mean time I will continue my search for which circuit may be the cause.

Mark
User avatar
LOUDthud
Posts: 464
Joined: Tue Sep 25, 2007 9:27 pm
Location: Texas

Re: House Ac line noise

Post by LOUDthud »

Can you hear the noise on an AM radio?
markr14850
Posts: 204
Joined: Mon Jun 18, 2007 6:16 pm

Re: House Ac line noise

Post by markr14850 »

So I have been trying to figure out if the aweful AC line noise in my home is from my house or outside caused.
Does anyone nearby have a string of LED Christmas tree lights running? That makes some crazy noise.
User avatar
M Fowler
Posts: 14036
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: House Ac line noise

Post by M Fowler »

Well tonight I removed three helix light bulbs and I see someone screwed in three more in my garage lately.

I told everyone we don't use those. I had this problem before with those noise inducing bulbs. Off to Menards tomorrow to get different bulbs and see if that helps.
Cliff Schecht
Posts: 2629
Joined: Wed Dec 30, 2009 7:32 am
Location: Austin
Contact:

Re: House Ac line noise

Post by Cliff Schecht »

Mark I have used AC line filters in amps before and did find a dramatic reduction in noise caused by noisy AC lines. A lot of the plugs in my house are two prong and I get a nice loud pop in my surround computer speakers every time the AC kicks on. When I run the speakers off of a line filtered wall strip, the noise transients are killed. Same in my amps, I can hear when a big motor kicks on in my amps until I add a line filter.

If you don't have one and want to try one out, I have more than I could ever use and would send you one free if you paid shipping.
[img:800:508]http://www.syntaur.com/images/4015-Lg.jpg[/img]
Cliff Schecht - Circuit P.I.
User avatar
Reeltarded
Posts: 10189
Joined: Sat Feb 14, 2009 4:38 am
Location: GA USA

Re: House Ac line noise

Post by Reeltarded »

omg I didn't know that thing existed.

Thanks for bringing it up, Mr. Cliff!
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
Gibsonman63
Posts: 1033
Joined: Wed May 27, 2009 1:59 pm
Location: Texas

Re: House Ac line noise

Post by Gibsonman63 »

Cool, Cliff. Where do you order those?
brentm
Posts: 391
Joined: Sun Aug 21, 2011 3:55 pm
Location: Olympia. It's the water!

Re: House Ac line noise

Post by brentm »

Would using a ferrite bead on the power cable help reject unwanted noise?
User avatar
M Fowler
Posts: 14036
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: House Ac line noise

Post by M Fowler »

Cliff that would be a good idea to start using those., thanks.
User avatar
Aurora
Posts: 765
Joined: Mon May 26, 2008 7:51 am
Location: Norway - north of the moral circle!

Re: House Ac line noise

Post by Aurora »

not tryin' to be the "wise guy" around here, but those filters have been standard in instrumentation electronics for decades now. Most of them are LC or CLC some form or another, - some rely on ground for proper function, some are not..
just look at the schematic in Cliffs picture...

Mark - what's going on in your neighbourhood??
Any heavy power users in your local grid, like heavy machinery??

EDIT: Filters like that are also common on most modern "what-have-you" with switch-mode PSUs, to prevent noise from getiing OUT of those units...
davent
Posts: 236
Joined: Fri Apr 07, 2006 1:45 am
Location: Southern ON

Re: House Ac line noise

Post by davent »

Being cheap i've been using DIY RFI filter's rather then buying the integrated IEC/RFI inlet.

[IMG:800:600]http://i216.photobucket.com/albums/cc30 ... G_0775.jpg[/img]

[IMG:640:393]http://i216.photobucket.com/albums/cc30 ... Filter.jpg[/img]

dave
User avatar
M Fowler
Posts: 14036
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: House Ac line noise

Post by M Fowler »

I doubt if there are heavy users on my grid I'm in a suburb with no business around.

But all of a sudden all my amps started this horrible raspy buzz. This is even Redplate amp and Dr Z amps that had no hum not just my builds.

In a prior post awhile ago I mentioned I found this helix light bulb at the base of my basement stair way when I replaced that bulb my noise completely subsided. Now I have the same damn noise and found six bulbs last night which I replaced today and same noise. I have been going around unplugging fridges and anything attached to the wall. I need to get some help and continue with switching the breakers to the house and see if I can isolate the area. Must exclude my home before I decide its grid related.

Mouser has a lot of those IEC filters rated for many different amps and they have a data sheet showing internal schematic.

Mark
ApexJr.
Posts: 225
Joined: Tue Apr 11, 2006 2:46 am
Location: Torrance , Cal
Contact:

Re: House Ac line noise

Post by ApexJr. »

Gibsonman63 wrote:Cool, Cliff. Where do you order those?

I have a bunch of these in stock at $2.00 each
IEC receptacle with 6 Amp filter
http://www.apexjr.com/images/APEXJREMIFILTER1.jpg
listed on my jack page on my website

Steve
C Moore
Posts: 1266
Joined: Mon Oct 22, 2007 9:28 am
Location: USA, California, 94585

Re: House Ac line noise

Post by C Moore »

It is the shared/crappy ground as much as anything.
Put your chosen room on a dedicated circuit....copper rod into the ground.....you will not need any "filtering". I was amazed at the problems it solved in our house.
RF would be another issue.
Best
User avatar
M Fowler
Posts: 14036
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: House Ac line noise

Post by M Fowler »

Behind a bush there was a landscaping light power transformer plugged into an outdoor receptacle that I didn't know about. :evil:
Post Reply