This is driving me nuts Part2

glemay

Ok, if some of you remember my dilemma with my Audigy 2 ZS soundcard, all I can say is something is wrong.

After sending my soundcard out to be inspected over one month ago without respone, today I received a new one. Put it in and hmmmmmmmm. Damn it! The hum is still there, I can't get rid of it.

I've tried a different receiver, different source, different cables, plugging the computer and reciever directly into the wall and different material and now a different sound card. And after all that I cannot get rid of this hum.

What could be the probablem?

Thanks, any help is appreciated.

Gerald

dorokusai

Have you tried replacing your computer power supply? Have you tried plugging them all into a power strip?

Sorry, I don't recall your thread about the problem, my memory is in the toilet.

Line noise is almost always line induced. It's either a bad power supply, or a ground loop IMO.

glemay

Doro,

No I haven't tried replacing my power supply, and yes I've tried plugging them all to a power strip. But why would my power supply be bad? My computer has been running fine. Please explain, sorry, I don't follow you.

danger boy

make sure the sound card is seated firmly.

make sure the speaker wires are not touching anything or lose.

if your power cord and speaker wires cross. .that can add a hum to your audio.

try a cheater plug where you plug your computer into the outlet


please explain how your sound card and recevier are connected to each other.. and how the speakers are connected to it.

dorokusai

A component doesn't have to completely fail to reach a state of unreliable operation. It's just a thought as hum is typically line induced or a shielding problem.

I see it all the time in my line of work.

As a side note: I fried the FDD port on my Mobo by accidentally connecting power incorrectly to the FDD drive....port is dead, 100%, but computer has ran fine for two years. Just an example.

TheReaper

If your sound card is capable. An optical digital cable will electrically isolate your computer and receiver (no electrical connection).

glemay

A friend just helped me figure it out!!! It's my actual power coming out of the wall. The question is what do I do know. My friend told me to get a battery backup or upc or ups? Can't remember. What do you guys think?

dorokusai

Try a cheater plug as mentioned before, and see....line induced AC hum.

If you have series wired outlets, you may have one out of series or in other words, wired incorrectly.

You mentioned it's a dedicated breaker and line.....? Make sure it's wired correctly, to include at the breaker box. Your hum may be coming from the common ground.

glemay

Could you explain what a cheater plug is?

I don't know how everything in the house is wired exactly but it is not just the one plug. I tried a few plugs on the second and third floor(my room) and it is still there.

The soundcard it connected to the receiver via RCA to mini-jack and the speakers are hooked up the only way I know how to wire them to a receiver.

I believe it's just dirty power. We plugged in to the battery backup for our phone system and the hum disappeared.

So now what should I buy, a battery backup/upc or a something like a power bar from panamax or monster power with noise filtration? Or...

dorokusai

A cheater plug is an adapter that coverts a three prong outlet into a two prong oulet....essentially removing the ground potential from the oulet.

sowen010599

Usually, I'd say maybe 90% of the time, it's because the computers case is not grounded. With most any PC, if there is no ground, you can actually get a good tingle from touching the bare metal case, assuming you are well grounded (concrete floor, bare feet, touching something else that is grounded etc.). So what you end up with is 120v 60hz current running rampant in the computer's chassis, along with every other component that shares a connection with it. Since the ground is shared because of audio connectors, it sets up a nice 60hz hum in the system. But it doesn't necessarily exist only when using the computer for a source. Sometimes the hum is constant across all sources because of the now rampant AC voltage in all devices attached to the computer (the receiver/pre-pro, sub, amp, everything).

A cheater plug will not work unless the outlet itself is grounded, which they aren't always, especially in older buildings. So that really only leaves two possible solutions. First, and possibly the best, is to ground the outlet properly. This can be done by running a line to the houses ground rod, a cold water pipe, back to the breaker box, or even sinking a new ground rod. You should check building code first. Sometimes the entire building is required to use a common ground. Secondly, you can make a jumper and use the neutral as a ground, they all end up at the same place anyway. In this case, you would make a jumper wire and connect the terminal that the white wire (neutral) is connected to to the ground terminal on the outlet. Sometimes this doesn't always work out so well as you can end up with a lot of electrical noise in the ground this way.

Any way you do it, a computer needs to be grounded. In my on-site kit I carry a ground tester. It tells me if the outlet is grounded. See, some surge suppressors and UPS units, can not function correctly in the case of a power surge without a ground connection. So it there isn't one, we have to call in an electrician to install one.

Oh, and FWIW, a UPS will not solve a ground problem. If the UPS is not grounded, then the computer still won't be either.

glemay

Is it possible for everything to be well grounded but still have dirty power. Our house is fairly new, 4 years old I think. And I have never received a shock from my computer. How can I tell if my computer is not grounded?

sowen010599

For you, if you have a higher-end (computer) surge protector, they will usually have a ground fault light to alert you to a ground problem.

Yes, you can have a good ground a noisy power. One situation I know of occurred because of a deep freezer in a garage disconnected from the house. Different circuits but fed from the same mains. Every time the freezer kicked in, everything would start buzzing.

dorokusai

Sowen - I have to agree/disagree with a few points.

Secondly, you can make a jumper and use the neutral as a ground, they all end up at the same place anyway. In this case, you would make a jumper wire and connect the terminal that the white wire (neutral) is connected to to the ground terminal on the outlet. Sometimes this doesn't always work out so well as you can end up with a lot of electrical noise in the ground this way.

That is against code in my state, but perhaps yours is different.

Any way you do it, a computer needs to be grounded. In my on-site kit I carry a ground tester. It tells me if the outlet is grounded. See, some surge suppressors and UPS units, can not function correctly in the case of a power surge without a ground connection.

I agree completely that gear, in any form needs to be grounded. I would also consider this a no-brainer as how can you surge arrest without a ground? I know what you are saying, it's the wording that puzzled me.


For you, if you have a higher-end (computer) surge protector, they will usually have a ground fault light to alert you to a ground problem.

Yes, most do. That is actually how I found a wiring problem with my HT room outlets. Two of the 6 outlets were wired out of series, thus creating a ground loop AND a 60.

Oh, and FWIW, a UPS will not solve a ground problem. If the UPS is not grounded, then the computer still won't be either.

Agree, as you can't solve a problem unless you start from the beginning.

Usually, I'd say maybe 90% of the time, it's because the computers case is not grounded. With most any PC, if there is no ground, you can actually get a good tingle from touching the bare metal case, assuming you are well grounded (concrete floor, bare feet, touching something else that is grounded etc.).

If you are getting shocked when you touch your comp, you need to fix it, it's never an acceptable condition. I've built and used hundreds of computers and never been shocked by them. Perhaps my local IT has some personal experience, but either way, shock means AC problems. Your computer is grounded via its plug. If that isn't the case, then it's troubleshooting time.

sowen010599

I am not an electrician, hehehe. Just an IT freak. Everyone should check local code before making any structural or electrical changes. And, it's always best to consult/hire an electrician if in doubt AT ALL.

People get shocked from there case when their ground potential is greater than that of the neutral wire, and no case ground (third prong) is present, or......again still if their ground potential is greater that that of the earth ground.

Here in Texas, it is extraordinarily common. We have lots of old buildings. When it gets really dry (not uncommon when it's 105 degrees) earth grounds don't work as well. In fact, most will tell you to "water your ground" every couple weeks. Put a soaker hose on the ground rod for a couple hours if the ground is really dry. Many will tell you to water your foundation in dry months to avoid cracking, this serves the same affect by proxy. Even with that, there can be problems with the ground. Corrosion is a common issue. If the wire/clamp is corroded where it attaches to the rod, it can have a very negative affect. I usually recommend to people having ground problems to have 2 additional rods sunk and wired in series with the original. That seems to have the best reliability. With an earth ground, surface area is king.

Those jumpers, ugh, I couldn't tell you how many times I have seen those. It's never a good solution. Probably the biggest problem with that is with a case grounded device, something like a drill, saw, even a computer. If the ground/neutral is poor, you can become part of the circuit (path to ground), ouch.

dorokusai

We used to urinate on ground rods in the desert to ensure their benefit.