Newbie - Hum in my system (yes, I read the sticky thread)

[ceningolmo]

Sorry... I just realized I should have posted this as its own thread rather than tacking it on to the ground loop FAQ thread above.


I apologize, as this may be a profoundly stupid question. But, I need some clarification, so I will ask.

A quick list of what is hooked up... I don't know if anyone will need specifics to help me, but better safe than sorry.
Kenwood VR-8070-S Receiver
Sony DSP-NS775V DVD player
Dish Network 811 HDTV Receiver
D-Link DSM320 wireless media server

I do not currently have a power conditioner. I have a surge suppressor, but I don't believe it does any of the isolating or filtering that more expensive units do.

I have a buzz in my home theatre system. I recently purchased the Kenwood receiver, and the buzz started when I introduced it to the system. So, my first inclination is that the receiver is the culprit. My problem is determining how to fix it.

According to articles I have read, on this site in particular, ground loop hum is a common problem. When the ground loop problem is described it is generally referenced as an immediate problem that remains constant while the system is powered up. Perhaps I am wrong in this perception?

Is there a difference between a hum or buzz associated with ground loop problems and the buzz associated with some sort of line interference? I know that I should route my power, audio/video interconnects, and speaker interconnects seperately in order to prevent interference. Is this a different problem than the ground loop issue? If so, how does one deal with it?

My system never had a hum prior to the introduction of my new receiver. Also, the hum does not start immediately upon power up. Typically it is about 20-30 minutes in to music, movies, or TV before the hum becomes present. Does this indicate a different type of problem?

Sorry if this is all covered in an article somewhere. If it is, I just haven't found it. I would appreciate any help you can provide.

Thanks,

Ross

 

[sjdgpt]

I do not currently have a power conditioner.


and the buzz started when I introduced it to the system. So, my first inclination is that the receiver is the culprit. My problem is determining how to fix it.

Is there a difference between a hum or buzz associated with ground loop problems and the buzz associated with some sort of line interference? I know that I should route my power, audio/video interconnects, and speaker interconnects seperately in order to prevent interference. Is this a different problem than the ground loop issue? If so, how does one deal with it?

My system never had a hum prior to the introduction of my new receiver. Also, the hum does not start immediately upon power up.

Typically it is about 20-30 minutes in to music, movies, or TV before the hum becomes present. Does this indicate a different type of problem?

Always start with the basics. You did something (new receiver), now you got a noise. You don't hear it when you start the equipment (doesn't mean it isn't there.... you don't hear it), and later you hear the hum.


Yes, the receiver could be bad. If the hum truly appears over time, and is not present at equipment start (just because you dont hear it, doesnt mean some hum is not there).

Or you could have something as simple as a poor fitting RCA connection. A very common problem. And I am sure you moved your cables around for the new receiver.

You could have a poor fitting electrical receptacle (on the surge protector or power cable).

A power cable plug could be failing (hearing the hum over time would be a good possibility as the plug would heat with time).

Ground to the Dish unit.

Poor fitting coaxial cable from the Dish to the receiver or switching system.

There are literally dozens of possible sources of a ground loop problem. Any of which could have resulted from moving the equipment around to locate the new receiver, or just their time to go, etc.

Yes, HUM is different than buzz. mouth the words. M sound versus Z sound. Repeat. Holding the sound MMMMMMMMMMM versus ZZZZZZZZZZ (or hiss SSSSSSSSSSSSS). Hiss at high volume levels with no signal is typically white noise (the receiver amplifing the background noise of the equipment).

Surge protectors do not include noise suppression circuits. But the cost of a line conditioner with surge protection is usually only a few $ more than a basic surge protector. Of the shelf (generic brands) of line conditioners with surge protection can be had at Wally World, Home or Office Depot, Rat Shack, SearsMart etc for as little as $30. For most of us, a $30 line conditioner with surge protection is all we need. I saw a nice 8 receptacle surge protector with line conditioner at Rat Shack for $55. Bigger bucks does not always equate to a better unit, just more joules of protection, and more receptacles to plug in our toys.

A line conditioner is not going to solve a ground loop problem. A line conditioner will solve noise interferce problems from the heat strips in your 20 year old central HVAC, the wife using the vacuum cleaner in the next room, the neighbors arc welder, the Ham Radio operator on the next block, and a lighting strike in the next state.

A line conditioner is not going to solve the problem from using $1 RCA patch cables running next to the power cord of your receiver or TV.

Hope this all helps.

 

[ceningolmo]

Steven- Thank you much for the response. As with many things, I know just enough about this stuff to be dangerous, not enough to do any real good for myself.

Regarding that actual type of noise, I would say it is more of a buzz than a hum. And, it is definately not a hiss. I have dealt with the hissing noise in other circumstances and this is not like that.

So... based on what you told me I have a lot of options for things that could be causing the problem. As you said, start with the basics.

1. Check the interconnects between equipment.
-I am currently using TOSLink digital between my HDTV receiver and my D-Link Media server and the receiver. I am using a coaxial digital audio interconnect between my DVD player and the receiver. Are these digital audio cables susceptible to the same type of interference that an analog RCA type cable is?
-I am using all component video cable for video connections between DVD, HDTV, Media Server and the Receiver. Can a faulty connection on the video end introduce noise in the system?

2. Check the electrical receptacle.
-As I said originally, I am only using a surge protector/power strip. Is there a way for me to verify that I truly have a poor connection? Is it as simple as wiggling the plug to verify if it is solid, or do I need actually check the receptacle itself in some way?
-I believe replacing a receptacle is dirt cheap. If I suspect there is any connection problem, it is better to just assume a replacement will help?

3. Check power cables.
-I am assuming I should do this for every component, not just the receiver. Is this correct? Since all of the components are new within the last 6 months, I doubt I am going to find a cord that is heavily worn. Can I simply check for a cord that is getting unusually warm? Is there another way to check this?

4. Ground the dish unit.
-Not sure on this one. If my dish unit comes with a 3 prong plug, I assume it is grounded. Do I need to ground the dish itself, or the HD receiver? I would probably need some help from someon on how to go about properly grounding either of these items?

5. Get a line conditioner of some sort.
-A trip to wally world later today should solve that problem. Anything in particular I should look for?

I think I understand most of this, and hopefully a little help will come on the parts I don't understand.

Again, thanks for the help!

Ross

 

[sjdgpt]

As you said, start with the basics.

1. Check the interconnects between equipment.
-I am currently using TOSLink digital between my HDTV receiver and my D-Link Media server and the receiver. I am using a coaxial digital audio interconnect between my DVD player and the receiver. Are these digital audio cables susceptible to the same type of interference that an analog RCA type cable is?
-I am using all component video cable for video connections between DVD, HDTV, Media Server and the Receiver. Can a faulty connection on the video end introduce noise in the system?

A decent cable (not the $2 RCA patch cable) is going to be adaquate for noise suppression. TOSLinks are pretty good cables, as well as the component video cables.

But a connection on any cable can be faulty. Usually it would be a loose fitting connection. The Toslink can be faulty, but I suspect it would be a huge error problem, not a subtle problem line a bit of hiss.

2. Check the electrical receptacle.
-As I said originally, I am only using a surge protector/power strip. Is there a way for me to verify that I truly have a poor connection? Is it as simple as wiggling the plug to verify if it is solid, or do I need actually check the receptacle itself in some way?
-I believe replacing a receptacle is dirt cheap. If I suspect there is any connection problem, it is better to just assume a replacement will help?

3. Check power cables.
-I am assuming I should do this for every component, not just the receiver. Is this correct? Since all of the components are new within the last 6 months, I doubt I am going to find a cord that is heavily worn. Can I simply check for a cord that is getting unusually warm? Is there another way to check this?

4. Ground the dish unit.
-Not sure on this one. If my dish unit comes with a 3 prong plug, I assume it is grounded. Do I need to ground the dish itself, or the HD receiver? I would probably need some help from someon on how to go about properly grounding either of these items?

Connections are simple and difficult to check... a poor fitting connection is obvious.... try grabbing, shaking, twisting etc the connections.... if something gives, you found the problem. Look for burnt plug ends. It happens.


The dish unit comes with a 3 prong plug for a reason. The receptacle itself should have a proper ground.

Many home electrical systems leave a bit to desire regarding grounds. Many outlets will share ONE common ground. It generally meets code, but can be a problem if the common ground is poor quality (loose, corroded etc).

Ground loops can be generated if all of the receptacles do not share a common ground. This can happen if the household wiring is old, the dish unit is connected at the other end of the house etc.

5. Get a line conditioner of some sort.
-A trip to wally world later today should solve that problem. Anything in particular I should look for?

Look for a unit that lists EMI & RFI suppression. I think WallyW is selling an unit form Philips. Should be about $40 to $60 if my memory is correct.

Joules are the amount of electrical suppression. Bigger the joules rating, the greater the protection. Noise suppression is harder for consumers to judge... too many terms that may or may not be meaningful... but read the literature and feel the weight of the unit...... heft can be your friend.

 

[ceningolmo]

Again, Steven, thanks for the help!

1. I checked all my interconnects and all looks solid. Double checked the ends on all the audio cables, and they look good. And, since most of them are brand new, I wouldn't expect a problem with these any way.

2. Replaced the two wall outlets I use most commonly with "Industrial" outlets.

3. Found a dandy surge suppresor/line conditioner at Lowes for $25. 8 outlets, 2000 joules of protection, and EMI/RFI filtering. Box said that the filtering effectively dropped interference noise by as much as 50db. So, between the new wall outlet and the new power conditioner, the power situation has to have improved substantially.

Unfortunately, I am still experiencing an intermittent buzz. All of my components are powered through the surge suppresor I just purchased (including my HD Dish receiver). So, I believe this eliminates ground loop as an issue. Correct?

When I orginially posted a couple of days ago, the buzz always became audible about 30 minutes after powering up. Now, the buzz is only present once in a while. It does not become audible consistently. And, once the buzz is audible, I can simply power down the receiver and power it back up to remove the buzz. Sometimes that will remove the buzz for a long time. Sometimes the buzz shows back up again an hour later.

I am no expert in this stuff, so I don't have the foggiest clue what this type problem might be related to. The only thing that I continue to fall back on is this; I only started having this problem after I introduced the new receiver in to my system.

Still needing help from some generous expert... thanks again.

Ross

 

[sjdgpt]

Unfortunately, I am still experiencing an intermittent buzz. All of my components are powered through the surge suppresor I just purchased (including my HD Dish receiver). So, I believe this eliminates ground loop as an issue. Correct?

When I orginially posted a couple of days ago, the buzz always became audible about 30 minutes after powering up. Now, the buzz is only present once in a while. It does not become audible consistently. And, once the buzz is audible, I can simply power down the receiver and power it back up to remove the buzz. Sometimes that will remove the buzz for a long time. Sometimes the buzz shows back up again an hour later.

No, a single line conditioner is not going to always solve a ground loop problem. If the problem is with the receiver (or another component) within the system, the ground loop problem will still be present.

Changing the switch setting on the receiver and removing the noise pretty much indicates a noisy receiver problem... most likely the volume knob or the internal volume electrical contection. Are you using a remote or actually turning the knob to remove the noise? Knobs are moving parts, usually quite inexpensive components, and prone to wear/tear/ and shipping damage.

 

[ceningolmo]

I am using the remote to do any volume adjustments. And, turning the volume down does not lessen the buzz. The only way I found to remove the buzz is to shut the receiver off and turn it back on again.

Is it a good idea for me to try to look for loose connections/components inside the chasis of the receiver? Or, would now be a good time for me to contact customer service at Kenwood?

Thanks,

Ross

 

[sjdgpt]

I am using the remote to do any volume adjustments. And, turning the volume down does not lessen the buzz. The only way I found to remove the buzz is to shut the receiver off and turn it back on again.

Is it a good idea for me to try to look for loose connections/components inside the chasis of the receiver? Or, would now be a good time for me to contact customer service at Kenwood?

Thanks,

Ross

Stay out of the chassis. Warranty. Don't know what you are looking for.... yada yada yada.

Turning the receiver on/off to fix the noise indicates a problem in the receiver.

Send it back and get a replacement. It is preferred to get a replacement, rather than letting somebody TRY to repair it.