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malikrm
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Speaker Buzz/ White Noise

I am relatively new to this Hi-Fi thing, and just switched over from my old receiver to a pre-amp/power amp set-up and I noticed that once I power up the power amp, regardless of the pre-amp's volume (so long as it is on) there is a faint buzzing or white noise being pushed through the speakers. Is this commonplace for pre/power amp setups, or have I done something wrong here, and how can i minimize this noise? Thanks!

mrlowry
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Re: Speaker Buzz/ White Noise

Is the sound at a consistent volume over MOST of the preamp's volume range? If so the sound is most likely emanating from the preamp. If this sound is very low in level or you have really efficient speakers this could be completely normal. Also most receivers pull a trick where if there is no signal coming IN they completely mute the output so you don't hear this low level background noise. The problem of course is that this muting threshold can remove tiny inner detail too which is why high-end products don't us it. Please provide more information on the specifics of your equipment.

malikrm
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Re: Speaker Buzz/ White Noise

The sound is constant over all frequencies, and though it cannot be hear unless standing near the speakers, does this cause distortion at low volume listening? The setup is a rotel RC-1082 preamp and a RB-1080 power amp. I am using them to drive infinity intermezzo towers although the same sound is generated when driving a pair of older KEF's

mrlowry
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Re: Speaker Buzz/ White Noise

How close to the speakers are we talking about? Have you talked to your dealer about it? You might want to stop into the show room to see if his demos do the same.

Jan Vigne
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Re: Speaker Buzz/ White Noise

You first have to identify whether you are hearing a "buzz" or a "hum" which are both low frequency in content and normally related to a grounding/isloation problem or whether you are hearing some other sort of noise. A ground loop will typically produce a "hum" which is 60Hz noise.

Lower the volume on your pre amp and disconnect one of your interconnects at the CD player end. Raise the volume slightly and touch the center pin of the RCA on the interconnect you have just disconnected. The noise you hear is a 60Hz signal. If the noise you are hearing through your speakers isn't 60Hz, then you have a different problem then a straight ground loop.

"Buzzes" often come from interconnects not dressed properly or other situations not related to the equipment per se.

"White noise" is what you hear in between FM radio staions when the mute switch is defeated. It is broad spectrum noise that has considerably more high frequency content than either a "hum" or a "buzz".

Once you determine what sort of noise is present and at what distance it is audible, we might be able to provide more assistance.

malikrm
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Re: Speaker Buzz/ White Noise

I would describe it as sounding more like a hum than a buzz, and when i removed one of the interconnects, it amplified the sound i was hearing. However, the sound does not seem like it is just the 60Hz cycle, because there is an openness to it which is why i described it as like white noise, though that low frequency hum is the most predominant sound. If the room is extremely quiet, i can hear the noise at up to 10 ft away.

Jan Vigne
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Re: Speaker Buzz/ White Noise

I would start by investigating a ground loop. If there's 60Hz anywhere in what you are hearing it is ground plane related. Phase distortions within your speakers or room might lead to an "open" sound with either a buzz or hum.

Start by placing something like, "tracking down ground loops" in a search engine and read about where the problem is most likely to originate. With separates the most common cause is improper AC wiring and/or components sitting at different ground potentials relative to AC ground. You can begin to trace the problem by unplugging (AC and interconnects) all components other than your power amplifier and listening for the noise. Add back one component at a time until the noise appears. At that point you've found the originator, now you just have to solve the problem. Go down to the hardware store and spend a few bucks on an outlet tester. You need to know the outlets are wired correctly before you do much else.

mrlowry
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Re: Speaker Buzz/ White Noise

Is the stereo connected to any video sources? If so try disconnecting the video source from the preamp and see if the sound goes away.

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