Noise, power conditioners, and aftermarket power cables

[Sams]

I'm hearing noise from my tweeters when the amp is turned on(no music being played). I experienced the same issue with my previous setup. I like to turn up my amp up to the 70s for engaging listening. I feel the noise gets louder in tandem with the music when I turn it up.

My setup consists of a denon 4520ci sitting on top of an entertainment center, under a wall mounted plasma TV. Several cables dangle on top of each other on the back of the entertainment center. I used monoprice cables for my previous setup. This time I used bluejeanscable to eliminate the issue. No change.

My questions are: do several cables in close proximity introduce noise to the amplifier? Is my plasma causing the noise? Will a power conditioner eliminate the noise? Will an aftermarket shielded power cable for my denon eliminate the noise?

I purchased my speakers for clarity(revel f12). My previous setup was a denon x4000/energy rc 70. That sounded really good, but not as exciting as I wanted(I guess the audiophile word would be very warm). I think the noise is more distracting through the revels, I want to enjoy them loud and clear. Im really hoping I'm not stuck with noisy ac power from my outlets, with nothing to do about it.

Bonus ?: is cable TV supposed to sound poorly recorded over a nice stereo, whether the amp is set to pure direct, stereo, Dolby digital?

Thanks,
-Sam

 

[ImcLoud]

OK, most likely this is a phase issue.

Common when you have 2 components of your system plugged into 2 separate outlet strings that are on 2 separate breakers and each of them breakers is on a separate leg...

Most of the time it is a TV, since they are sometimes far from the av rack, also subwoofers are prone to this...

Simple to figure out, run an extension cord (with a ground) to the tv or component out that is not on the same breaker. if it goes away that is your issue, dont worry you can move the breaker, or hire someone to do it rather, if you never did it before... another way to figure it out faster is to just unplug the hdmi or anything else that connects it...

Now if that is not the issue, try taking away any coax that comes from the street or dish, etc...

If that makes it go away they sell devices to isolate them...

Now a poor ground can also be the issue, you can test this by running a wire from your ground to your system, ground the amps chassis and see if it goes away, or have an electrician check it out for you... If you have old non grounded cables in the house, think about adding a 20a 12g circuit for your system...

I have hunted these things for a while, I never found it being wires too close or touching, it was always either a single piece of equipment that once removed also removed the hum, or once I had the issue with the separate phases of power, I had a bad ground before, etc...

If everything is plugged into the same outlet, UNPLUG everything from everywhere, get an mp3 player as a source plugged directly into your receiver and see if there is a hum there, if it is not, start adding components until it comes back, the last component added is the culprit.
If the hum is there with a basic source, receiver setup, then I would plug it in somewhere else..

 

[Speedskater]

Ham radio operators are always complaining about the neighbor's plasma TV causing interference. Cable TV Set Top Boxes and DVD players can also cause interference but only within about 3 feet.
So why not troubleshoot?
Unplug everything. AC power, interconnects, telephone, internet and cable TV.
Connect the speakers, then plug-in the receiver. Using a battery powered music source, do you still have the problem?
If not connect one unit at a time and check again.
For this test use only one AC power outlet strip.

 

[Sams]

Thanks guys, I have some experimenting to do

 

[WaynePflughaupt]

What kind of noise is it? If it’s hiss, that comes from the electronics, from one of the components having poor signal-to-noise properties. You might try switching from one input to another to see if you can isolate a noisy component.

If the noise is more like a hum, then that’s an electrical issue and the suggestions the others provided will help.

Yes, unfortunately it’s not unusual for cable TV programming to sound bad. It’s not just cable TV, we get poor audio all the time from shows from the major networks. ABC seems to be particularly bad. It’s one of the downsides to having a nice, accurate system.

Regards,
Wayne A. Pflughaupt

 

[Hookedonc4]

We actually picked up 2 of these power centers from Monoprice. We didn't have a lot of noise but these old ears heard something so picked these up on sale for $79 and don't hear anything anymore. It appeared to clean things up...

 

[highfigh]

I'm hearing noise from my tweeters when the amp is turned on(no music being played). I experienced the same issue with my previous setup. I like to turn up my amp up to the 70s for engaging listening. I feel the noise gets louder in tandem with the music when I turn it up.

My setup consists of a denon 4520ci sitting on top of an entertainment center, under a wall mounted plasma TV. Several cables dangle on top of each other on the back of the entertainment center. I used monoprice cables for my previous setup. This time I used bluejeanscable to eliminate the issue. No change.

My questions are: do several cables in close proximity introduce noise to the amplifier? Is my plasma causing the noise? Will a power conditioner eliminate the noise? Will an aftermarket shielded power cable for my denon eliminate the noise?

I purchased my speakers for clarity(revel f12). My previous setup was a denon x4000/energy rc 70. That sounded really good, but not as exciting as I wanted(I guess the audiophile word would be very warm). I think the noise is more distracting through the revels, I want to enjoy them loud and clear. Im really hoping I'm not stuck with noisy ac power from my outlets, with nothing to do about it.

Bonus ?: is cable TV supposed to sound poorly recorded over a nice stereo, whether the amp is set to pure direct, stereo, Dolby digital?

Thanks,
-Sam

HDMI cables emit lots of noise- if you hear noise from the tweeters, it's very unlikely that it's on the power because it goes through the AVR's power supply and that has a pretty large transformer and filtering, which isn't going to pass much noise on to the speakers. Power supply noise doesn't usually make it to the output unless it's radiated into the circuit.

Move the entertainment center away from the wall, if possible- if you hear a change in the noise level, start separating cables. If you wrapped the power cords with any audio/video cables, separate them and always make sure any signal-carrying cables that are near power cords pass at a right angle. AV cables that are parallel to power cords can pick up hum and other noise more effectively than if they cross at a right angle.

If you want to find the culprit and you have a hand-held AM/FM radio, place the radio near the cables and set it to AM, moving the tuner dial through the range of frequencies until you hear the same kind of noise. Then, separate the cables and with the antenna as short as possible, move it close to each cable, one at a time. When you find the one that makes the most noise, re-route it or substitute a different one and see if it helps.

TVs definitely can introduce noise to a system- proximity and orientation make a big difference. That's the reason I mentioned moving the equipment away from the wall and TV.

Unplug the coax from the cable box. If the noise disappears, call the cable provider and tell tehm about the noise and make them ground the cable feed- they're notorious for NOT grounding it an that's an electric code violation. Also, if the ground doesn't help, have them install an isolator on the feed. It's possible that the cabling in your area is older and needs maintenance, or the line amplifiers aren't rejecting noise the way they should.

 

[Sams]

Thanks for the new responses. I've unplugged everything, tried new wall outlets, and moved the denon away from the plasma with no change.

I forgot to mention, I'm a few houses down from power lines... If that matters. Occasionally I'll see helicopters hovering over them for maintenance.

I was considering these entry level power conditioners, but will now add the monoprice suggestion to the list. http://www.crutchfield.com/p_299SP8AV/Panamax-SP8-AV.html

http://www.parts-express.com/tripp-lite-isobar6ultra-surge-suppressor--125-142

What stuck out to me was the emi/rfi noise filtration

I've heard mixed views on plugging a powerful amplifier into a power conditioner, naysayers say dynamics are compressed