Weird Sound

[G1OSE]

hi peeps
i have been happy with my system for a while now and find it great
but for the last few days i have been having problems
i have a sony set up all seperates with the 1080 reciever as the main power
the problem i am getting is that after a while and never a set time there is a weird noise that starts comming through
it is like a derderderderderderder really fast and constant and it slowly gets louder
ive checked everything but cant fix it
first i thought power interferance so re-wired it still no joy
then i thought it was the computer so turned it of no difference now the noise starts quiet but soon gets loud beond the point of being able to listen to it so i turn it off

can someone help me what is this?
how can i make it go away
i cant stand it any more
is it the amp-speakers-interferance
thanks for your help

 

[fraggle]

Have you tried switching to an unused input and seeing if it still happens?

And then try disconnecting all inputs?

If it still does it it might be a fault with the amp.

 

[G1OSE]

hi
when there is no sound then there is no noise it is only when there is sound
so if i switch it to a input with nothing in it it makes no noise but if i switch it between inputs wth sound the noise still happens
i have had the amp just over a year so i hope its not the amp
thanks

 

[G1OSE]

soemone at work today mentioned it could be the amp over heating does this sound right has anyone experienced this before?

 

[the mechanic]

Hi G1OSE,

I know this may sound strange but do you own a mobile phone?
I've heard a similar noise on both my PC and AV system. The problem :- mobiles send out a signal to the phone companies sattellite or whatever so they can check for signal strength/ position etc, this only occured when my mobile was close to the PC/AV and when I moved it away, hey presto :- NO NOISE.

Another possibility could be mains interference where you sometimes get stuff like central heating switching on, or the fridge/freezer. These kind of appliances could cause noise problems but maybe not as severe as I think you are getting, as they generally cause clicks/pops/bangs.
Check that the phono and speaker cables are not bundled together with the mains cables as this is another cause of noise/interference. You say there's no noise on un-used/disconnected inputs (as fraggle suggested you try), so could you have a speaker problem perhaps? Does the noise come through the speakers or from the amp itself? You say you re-wired it but did you also check for breaks in the speaker cables?

One last thing to try if you have a subwoofer is check the connections/condition of the cable as I had a loud buzz/rumble on mine and found that one of my cats had dislodged the phono lead and it was'nt fully connected.

If all this fails get the amp checked out at your local electrial repair shop (look in the phone book), it should'nt cost that much but will give you peace of mind. If it's ok then get the speakers/sub checked out next.

Sorry could'nt be of more help, let us know how you get on.

TTFN

 

[G1OSE]

wow thanks for that reply
firstly yes i have a phone well a few but they are not normally near the system and even if they are it is so regular that makes me think its not that and also its not the same noise that phones make equiptment make so i dont think it is that

i dont have any thing that switches on the fridge is under it but is always on so i doubt again it is that but it may be a possibilty

i rewired the system taking all power cables away and tied them up together
the phono cables and speaker wires are all together in a big mess at the back but there seems to be little i can do about that unfortunatly

the noise defo comes from the speakers and all 6 of them at that could be a speaker problem but i couldnt see what as it has just happened and i have changed nothing

i have just added a sub today so doubt its that

i have just checked and its still under a year old by 2 weeks so unless anyone has any ideas or anyway of checking the speakers or wires i may have to take it back but i cant live without it and cant really keep re-wiring it all the time

any other ideas?
cheers

 

[the mechanic]

Righto will have a think if anything comes to mind and get back to you.
Gotta go now as my telly progs are on.

TTFN

 

[G1OSE]

ok i spent all night listening to cd's testing it and it didnt happen
so could it be something to do with my cable box?
it may have been a fluke that it didnt do it but i wanna make sure before the warrentee runs out
cable box is on but not listening or watching it its just next to the amp
any more ideas?
cheers

 

[the mechanic]

Hi again,

You said in the last two replies that the fridge is under it?? and the cable box is nearby.

Does this mean that that the amp ect is sitting on or close to the system?, if so MOVE THE B****Y FRIDGE!! Fridges can be one of the worst sources of electrical interference going, and by siting your AV gear close to one may well be a cause of your problem.
If poss move it as far away from the system and dont plug it into the same wall socket as your AV (or multiway extension if you use one). Fridges, central heating, microwaves etc feed back a lot of crap into domestic power supplies (and not just your own but also your neighbours appliances can also effect your supply).

Try moving the cable box, fridge and any other equipment as far away as the cables will allow (try the fridge in another room if poss), then try each source connected to the amp one at a time and see how you get on.

Best of luck,

TTFN

 

[fraggle]

If you also have anything on top of an amplifier that is not good news.

If you look in the instruction manuals they all say you should leave a large gap above and to each side and the the rear of an amp to let the air circulate round it.

I know cable boxes are on 24 hours a day and do get hot.

IMHO I think over the year the amp has been running very hot when you've been using it and something has at last given up the ghost and is on the verge of packing in completely. Early Sherwood amps were known to do this, the DSP chip that decoded the DD5.1 and DTS got to hot and died.

If you only have 2 weeks warranty left then get it back to the shop NOW!!!!


HTH.


Rich

 

[G1OSE]

hey guys thanks for your replys
yes my system is above by about 10 inches and is plugged into a separate extension cord but of the same out let

the amp is in a sony repair centre as we speak hopefully it should be sorted soon

i will be buying a nice (hopefully cheap) shelving unit to take it all away i have been meaning to do so but never really got around to it will do now (any cheap recomendations?)

will let you no how it goes many thanks people!!!

 

[mjn]

Originally posted by G1OSE
the noise starts quiet but soon gets loud beond the point of being able to listen to it so i turn it off

from this description, its sounds as if a capacitor has failed, not charging / discharging correctly.

 

[G1OSE]

oh rite well i will let you no soon as the amp doctors are having a look at it right now!!!

how much do you recon a str db1080 is worth these days as i have been offered one
cheers

 

[the mechanic]

Hi again G1OSE,

Any news on the "poorly" amp yet??

Keep us up to date.

TTFN

 

[G1OSE]

nope took it to the amp doctors a sony repair centre and they had to order something but they didnt tell me what
should have had it back end of last week so they will be getting a call from me tommorow!
will keep ya up to date cheers!