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Discussion Starter · #1 ·
Hi all.. i have a annoying problem with my surroundsystem. To be spesific i have a problem with "noise" from it, in silent parts of a dvd film or a cd you can cleraly hear the (humming, buzzing noise... sorta like air leaking out of a tire thing) noise.


basics:


Rotel surround reciver (witch powers the senter and rear speakers)

Rotel Amp (powers front speakers)

Harman/Kardon DVD (digital coax cable between it and rotel reciver)

BW 604 front speakers, bw senter speker and some smal ones in the back


all kables in the system are of ok quality


annoyne have anny ideas as to what is causing this and if so what i shoud do to try and get rid of it ?
 

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Is it a

zz-zz-zz-zz-zz

um-m-m-m-m

or

schi-i-i-i-i-i-i-sh


buzz could be RF noise (timers, fluorescent lights, dimmers,etc)

hum could be grounding

schish (white noise) could be a failing component.
 

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Discussion Starter · #4 ·
the higher i turn up the volume the higher the noise gets. and it is stil ther after i turn of power to DVD player.


i guess the nois woud be most like a cross of Schi-i-i-i-i-sh thing and um-m-m-m-m thing.. depending on witch speaker i lissent to, the L-R front speakers have a deeper sound to em.. more like um-m-m-m then senter and rear speakers that have more of a schi-i-i-i-sh sound to em.


Components are just 2-3 years old, and i have changed DVD-player without it making a difference.


the room has fluorecent light, but they are always turned off when i watch films, and the noise dont change when i turn em on.
 

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Disconnect all cables from the amps except the power cord and speaker wires- IE disconnect all interconnects.


Does the problem go away?
 

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Discussion Starter · #6 ·
nope.. it's still there.. i have now tried close to ever possible combo of disconects.. including speakers..


1. disconecting all but coax to dvd = stil noise

2. disconecting all interconects = stil noise

3. disconecting all interconects and cable to L-R front amp = stil noise

4. all interconects, LR amp and senter dissconected = stil noise

5. all interconnects, LR amp and rear speaker disconected = stil noise

6. all interconects, senter and rear speakers = stil noise


whats next step ? coud it be the power cable ? most the audio/video eq. is on same 16amp line, but most of it was turned off when i tested now (only video that was stil on)
 

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So I'm hearing that with no interconnects connected you still have noise out of ALL 5 speakers?


That is quite strange, given that you have two seperate amplifiers.


It is not uncommon there to be a slight hum when no signal is present, but you shouldn't have enough to be particularly noticable at the listening position.


I think you've ruled out a ground loop. If you still have noise with NO interconnects- including video- connected then there is only one path back to ground thus no ground loop.


It is also unlikely you would have transformer hum on two seperate amplifiers. So we're left with RFI.


I would try to move the two-channel amp and speakers into a different room and different outlet and see if it still makes noise. It is also possible you have a bad power cable, but that is also unlikely since you are using two cables to the two amps.


You may benefit from a power conditioner to remove the noise from the power line.
 

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Discussion Starter · #8 ·
well.. basicaly the Amp for the LR speaker gets it's signal from the Recciver.. so if the reciver is the source of the problem.. the noise woud be precent in all channels...


dont think power line noise is that big a problem over her in litle old norway, atleast not that i have heard of.


I can try connecting the reciver to a different power outlett, but if that does not help annything ? then what is the reciver itself defect ? I have sent a mail to rotel support asking fore ther input to.


btw.. tnx for helping
 

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I'd suggest to start from 'ground zero'.


Pick one electrical power outlet/circuit (one that has no other potential to cause interference... fluorescent lights, timers, dimmers, refrigerator, etc).


Hook up ONLY the receiver and one set of speakers to that particular outlet.


Turn off all circuit breakers in your home (except the one for the receiver) and see what happens.


My thoughts are this should eliminate RF interference and possibly grounding problems.
 
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