Affordable AC line noise filtering

[amuro73]

I've been researching options for filtering noise that travel through my power circuit. I can hear the motor of my washing machine through my speakers! I know that plugging audio equipment into its own isolated circuit is ideal, but that's not an option now. So, I need a plug-in hardware to deal with the noice.

I know that part it is caused by ground loop. Upon someone's suggestion, I plugged in my power amp using a 3-prong to 2-prong converter, and the hum was reduced 80-90%, though not completely gone. The above waching machine motor noise was traveling through the ground line, apparently.

So, with all that said, I'm picked out some products -- if any of you have any experience with these devices, please let me know. Thanks!

Ebtech Hum X
This looks like just the ticket for isolating my power amp and removing the noise traveling through ground. A bit costly.

AudioPrism QuietLine
This looks intereting but since the plug is 2-prong, I'm guessing that it doesn't deal with noise traveling through the ground line. But this combined with above may eliminate all noise?


Triprite Isobar
This is a surge suppressor/noise filter. I know most cheap ones (even those that claim to have a filter) are ineffective, but these look like perhaps a higher grade one that may work.

Any other solutions? I'm hoping for <$100 total. At the very least, if I can isolate the power amp's ground line noise, I'll be happy. Thanks!

ari

[Albert]

Tripplite makes excellent products in my opinion, I have a bunch of their rack mount IsoBar 12 units, but I don't think that Tripplite will do much for your hum problem.

Of the other two, I'd probably go for the EbTech, although I personally haven't used it.

Another option is to maybe don't do the laundry when you are recording in your studio? tutt

[mikedaul]

Originally Posted by amuro73

I plugged in my power amp using a 3-prong to 2-prong converter

This is VERY DANGEROUS! Seriously - doing that can lead to fires, death, etc. Go back to plugging in the 3-pong end correctly and find a different way to eliminate the noise.

[vince @ speck]

It's a simple solution that's often overlooked... use a line filter on the offending source of line noise. Try an AC line filter on the washing machine!

[Ethan Winer]

Ari,

> I've been researching options for filtering noise that travel through my power circuit. I can hear the motor of my washing machine through my speakers! <

See the second half of this article:

www.ethanwiner.com/dimmers.html

It shows how to make a DIY RFI filter that's really cheap but very effective.

--Ethan

[amuro73]

Originally Posted by mikedaul

This is VERY DANGEROUS! Seriously - doing that can lead to fires, death, etc. Go back to plugging in the 3-pong end correctly and find a different way to eliminate the noise.

Yes, I realize that! It was tried just for a very short period to isolate/identify the problem. I have no intention of using any piece of equipment without proper grounding.

ari

[amuro73]

Originally Posted by Ethan Winer

Ari,

> I've been researching options for filtering noise that travel through my power circuit. I can hear the motor of my washing machine through my speakers! <

See the second half of this article:

www.ethanwiner.com/dimmers.html

It shows how to make a DIY RFI filter that's really cheap but very effective.

--Ethan

Yes, Ethan, you responded to another post of mine on the same topic a while ago. I'd really love to do what you're suggesting, but unfortunately I am stuck on figuring out exactly which part from Mouser or Digi-Key is the correct RFI filter for my needs.

ari

[amuro73]

Originally Posted by vince @ speck

It's a simple solution that's often overlooked... use a line filter on the offending source of line noise. Try an AC line filter on the washing machine!

Well, what I'm actually hoping to do is to plug an AC line filter on the power amp, so that that elment is isolated. The noise can travel through the rest of my system (I know it's not great, but for the time-being) as long as my power amp remains noise-free.

I am just researching and trying to figure out which AC line filtering product is the most cost-effective way to go.

ari

[amuro73]

Originally Posted by Ethan Winer

Ari,

> I've been researching options for filtering noise that travel through my power circuit. I can hear the motor of my washing machine through my speakers! <

See the second half of this article:

www.ethanwiner.com/dimmers.html

It shows how to make a DIY RFI filter that's really cheap but very effective.

--Ethan

Ethan and others,

Will one of these do it?

http://cgi.ebay.com/NEW-EMI-POWER-LI...QQcmdZViewItem

http://cgi.ebay.com/CORCOM-10VK6-RFI...QQcmdZViewItem

Thanks!

ari

[KurtR]

Depending on how much power you are using this little iso transformer might work. http://cgi.ebay.com/NEW-350W-MEDICAL...QQcmdZViewItem

I'm not 100% it would cut out all the noise but it should at least do something. I;ve seen used deals like this for under 100 bucks at a local shops and I've been wondering what they will do. Here's more info http://icm.computercci.com/pgi-productspec?PSO090

[Ethan Winer]

Ari,

> Will one of these do it? <

The photo of the first link doesn't show how many stages it has, but the second one does show that and this is definitely the right type.

--Ethan

[mikedaul]

Originally Posted by amuro73

Yes, I realize that! It was tried just for a very short period to isolate/identify the problem. I have no intention of using any piece of equipment without proper grounding.

ari

Good to hear

I feared you were running this way permanently and just looking to remove that extra 10% of noise...

[amuro73]

Originally Posted by Ethan Winer

Ari,

> Will one of these do it? <

The photo of the first link doesn't show how many stages it has, but the second one does show that and this is definitely the right type.

--Ethan

Thanks Ethan! That helps a lot. I'll try 'em.

ari

[Trancetones]

Buy a grounding pipe clamp in the electrical section of your home depot and a roll of green 12 guage wire and connect the clamp to a cold water pipe (I use the outdoor hose pipe.) Turn off your circuit breaker and remove the ground from the outlet for your audio gear and attach the wire from the ground screw on the outlet to the ground screw on the pipe clamp. Total cost about $25-

[Sensater]

Originally Posted by Trancetones

Buy a grounding pipe clamp in the electrical section of your home depot and a roll of green 12 guage wire and connect the clamp to a cold water pipe (I use the outdoor hose pipe.) Turn off your circuit breaker and remove the ground from the outlet for your audio gear and attach the wire from the ground screw on the outlet to the ground screw on the pipe clamp. Total cost about $25-

That's exactly what I did at my apt. It's an old building and most outlets are not grounded, but they are now! I bought the wire by the foot at Home Depot so it was pretty cheap. But does it have to be a cold water pipe? Also: I used a copper pipe that was exposed in the wall, which is water service for the upstairs apt. If I experience an electrical problem and electricity is shunted to the ground, does this present a danger for the upstairs water users? Or will the lesser resistance to earth mean that the juice will go that way for sure?
Sorry for the brief threadjack...
-Sen

[jaytmoon]

Originally Posted by Sensater

That's exactly what I did at my apt. It's an old building and most outlets are not grounded, but they are now! I bought the wire by the foot at Home Depot so it was pretty cheap. But does it have to be a cold water pipe? Also: I used a copper pipe that was exposed in the wall, which is water service for the upstairs apt. If I experience an electrical problem and electricity is shunted to the ground, does this present a danger for the upstairs water users? Or will the lesser resistance to earth mean that the juice will go that way for sure?
Sorry for the brief threadjack...
-Sen

Guys, Do not ground anything to a metal supply pipe in your home or apartment. You will put any plumber (or your self) into a direct risk for electrocution. You never know if there is a "break" in the metal pipe supply line with a plastic one. The only safe (for everyone) means to properly ground out an electrical device or panel is to run a copper gound wire outside to a grounding rod post driven into the (what else) ground. I'm not sure of the depth but I think it's 8 feet. Please check your local electrical codes for the proper grounding methods.

[nosebleedaudio]

Originally Posted by jaytmoon

Guys, Do not ground anything to a metal supply pipe in your home or apartment. You will put any plumber (or your self) into a direct risk for electrocution. You never know if there is a "break" in the metal pipe supply line with a plastic one. The only safe (for everyone) means to properly ground out an electrical device or panel is to run a copper gound wire outside to a grounding rod post driven into the (what else) ground. I'm not sure of the depth but I think it's 8 feet. Please check your local electrical codes for the proper grounding methods.

Then it MUST be bonded/connected to the main AC neutral/ground..
By code ALL grounds MUST be bonded together; ground rods, water pipes..