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#64259 - 03/10/07 05:37 PM Re: HUM HELP
Hullguy Offline
Desperado

Registered: 01/17/02
Posts: 380
Loc: South Weymouth, MA USA
Quote:
Originally posted by Dr_JB:
Hullguy,

I've experienced similar problems with my Anthem Statement amplifier, but I've not been able to isolate the problem. All I know is that the degree of hum is not consistent. I've yet to try the extension chord method.

This house was built in 61, with a 60amp service, but was updated to a 100 amp, in 85. Most of the breakers are on the upper rail. When you say that Supertom should be sure to have the new outlet installed on the same phase as the extension chord outlet, what exactly do you mean?

Also, my amp doesn't have a ground lead, but has a binding post for grounding. I grounded the amp to the grounding post in the main box. However, given that when there's a problem, the excess load is dumped to ground, I'm thinking this could actually harm my amp and have reconsidered grounding it to a nearby water pipe. Is this a good idea?

Any and all information, appreciated.

thanks,

John

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#64260 - 03/10/07 05:55 PM Re: HUM HELP
Hullguy Offline
Desperado

Registered: 01/17/02
Posts: 380
Loc: South Weymouth, MA USA
When the electricity comes into the house it enters on 3 wires. 2 of these wires are hot and typically attach to bus in the electric panel. One hot wire goes on the right bus and the other wire goes on the left bus. Each one of these bus is considered a phase, (the AC sine wave is out of "phase" between each bus or wire). The circuit breakers plug into this bus giving you your individual circuits. The way these bus are laid out in the panel causes every other circuit breaker to be a different phase.

The ground wire in a house is generated by running a wire to ground rod. In the old days you just used to attach the ground wire to the cold water pipe. You are still supposed to ground any metal systems, like plumbing, in a house. So, if you attached the ground from your amp to the water pipe, electrically, you have attached the wire to the same point as the ground in the panel. I think the way you have it is fine, as long as any humming isn't created or intensified.

The ground wire is designed to carry large fault currents. This is how a circuit breaker works. A large amount of current flows through the ground, in a fault situation, causing a sharp increase in heat. This heat bends a bimetal latch releasing the switch in the breaker.

I hope I wasn't too long winded and didn't leave anything out. If I didn't do a good job of explaining this feel free to ask more questions! Jim

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#64261 - 03/10/07 07:54 PM Re: HUM HELP
Dr_JB Offline
Gunslinger

Registered: 01/14/07
Posts: 215
Loc: Ontairo, Canada
Jim,

I think I understand. Just to be clear, though; if I have two circuit breakers installed, adjacent to each other, then, this pair is out of phase with each other, so that if I were to install a third, the outside pair would be in phase?

In my situation, the majority of breakers are on the top row, while the bottom row is nearly empty. Installing a new breaker on the bottom row, then, doesn't insulate or isolate it, in any way, from the breakers on the top row; correct?

It is as you say, with the three main wires coming into the house. Is there a way to create a separate circuit from the main box, entirely, so as to isolate the home audio equipment from every other electrical appliance in the house; or, is it just not possible to separate the two?

Jim, not long winded at all. I appreciate the response!

Thanks,

John

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#64262 - 03/10/07 08:53 PM Re: HUM HELP
gonk Offline
Desperado

Registered: 03/21/01
Posts: 14054
Loc: Memphis, TN USA
I'll leave hullguy to get the better answer to these questions, but typically the panelboard schedules I see at work alternate between the two (or three, in commercial work) phases - so the ones all at the top will still be spread across both phases.
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#64263 - 03/11/07 09:32 AM Re: HUM HELP
Hullguy Offline
Desperado

Registered: 01/17/02
Posts: 380
Loc: South Weymouth, MA USA
The circuit breakers alternate phases from top to bottom. Each panel is numbered, starting from the top left at 1. All the circuits on the left side are odd numbers, the right side even. So breaker number 1 and breaker number 2 are on different phases.
Breaker number 1 and breaker number 3, are on opposite phases. Breaker 3 and 2 are on the same phase. The phasing zig zags through the panel,ie.circuits 1,4,5,8,9,12,13,16,17,and 20 are on the same phase. 2,3,6,7,10,11,14,15,18,19 are on the other phase. This makes it easier to keep the loads balanced.

You can add a panel dedicated to just your audio equipment. To really isolate it from the other power in your house you would need to install a 240volt to 120volt/240volt isolating transformer with batteries. Now you have a UPS system for your stereo!

An easier way is to buy a single circuit UPS,like this,
http://www.tripplite.com/products/product.cfm?productID=2721
Hope this explanation helps! Jim

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#64264 - 03/11/07 03:07 PM Re: HUM HELP
Dr_JB Offline
Gunslinger

Registered: 01/14/07
Posts: 215
Loc: Ontairo, Canada
Jim,

Thank you for the excellent explanation. I'm just about to print it out, for personal reference.

I've never heard of a UPS; what is it? I've read through the tripplite specs and there's nothing mentioned about EMI/RFI filtering, which, I assume, is what some of these other power conditioners do. Is this a valuable feature to have, or is it unnecessary with a UPS? Can I achieve a UPS configuration with any of the items listed on this page:

http://www.surgex.com/products.html

which also include EMI/RFI filtering?

Jim, thanks for your help!

John

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#64265 - 03/12/07 08:05 AM Re: HUM HELP
taylodr Offline
Gunslinger

Registered: 01/23/07
Posts: 43
Loc: Richmond, VA
A UPS is an "Uninterruptible Power Supply" It simply means that you will not lose power to whatever is plugged in until the batteries die. If the power comes back on before then, you will never see the power go out.
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Outlaw Audio 990
Outlaw Audio 2200 (5)
Monitor Audio RS-6
Monitor Audio LCR
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#64266 - 03/12/07 08:19 AM Re: HUM HELP
taylodr Offline
Gunslinger

Registered: 01/23/07
Posts: 43
Loc: Richmond, VA
These are really good surge protectors (used by professional AV contractos), but none of them appear to be UPS's. They are surge protectors, meaning that they are intended to filter "noise" (electrical hums from other household loads: fridge, hair dryer, COMPUTERS) and protect from "spikes"
All this means is that it helps protect your sensitive electronics from getting potentially damaging over and under supplies of power along with helping filter out other unwanted signals in the power.
Believe it or not, while all of these normal culprits (washer, dryer, fridge, etc) do cause wierd effects on house power, computers and other digital electronic devices add tremendous amounts of "noise" to your home power.
Some reasonalble explanations for "Hum" often have to do with an insufficient ground of your whole system.
_________________________
Outlaw Audio 990
Outlaw Audio 2200 (5)
Monitor Audio RS-6
Monitor Audio LCR
Philips Ambilight 42" HD Plasma
Project Debut III

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#64267 - 03/12/07 08:21 AM Re: HUM HELP
taylodr Offline
Gunslinger

Registered: 01/23/07
Posts: 43
Loc: Richmond, VA
This is not a huge problem. It means that your things will still work, and is safe, but it also means that all the "nasties" getting fed back into your household power are hanging around instead of being escorted into the ground.
_________________________
Outlaw Audio 990
Outlaw Audio 2200 (5)
Monitor Audio RS-6
Monitor Audio LCR
Philips Ambilight 42" HD Plasma
Project Debut III

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#64268 - 03/12/07 09:38 AM Re: HUM HELP
Hullguy Offline
Desperado

Registered: 01/17/02
Posts: 380
Loc: South Weymouth, MA USA
Most UPS systems take the power from the house convert it to DC feed it through the batteries and then convert5 it back to AC. Because of the UPS doing what it does, the DC conversion, it should eliminate any noise injected on the power side! It also acts as a surge protector!

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