speaker buzzing/interference

[holden_stroker]

hi everyone, i've been watching this forum for a few months now and just recently decided to register here!! i love this place!!

i've done a little bit of a search on this topic but didnt come up with an answer to my problem.

i have the beloved "buzzing" sound coming through my speakers.

1. the louder i turn the volume up the louder the buzzing gets.
2. the buzzing sounds like its coming only out the tweeters
3. when i turn the treble right down, the buzzing fades away until you cant hear it, when you turn the treble up, it gets louder.
4. i disconnected all the RCA's going into my receiver, leaving only the main power cable there, and the buzzing is still there.
5. speaker wires run near power cables although when i moved them it didnt make any difference.


any ideas what else it could be? could my receiver be on its way out?

equipment currently being used is..

sherwood rx-203or receiver
sherwood isp550 floor standing speakers (3way)
sherwood cdc-6050r carousel player

i dont have another amp i can try although im awaiting my new wintal 7.1 receiver to turn up in the next couple of weeks.

thanks for anyone who can help me..

 

[m_vanmeter]

could be a filter capacitor in the receivers power supply, could be interference picked up by the speaker cables.

try hooking one speaker up with very short cable, have the speaker very close to the receiver - still buzzing ?

 

[holden_stroker]

hey thanks for the reply, i will try that if i come across any other speaker wire, although i dont have any spare at the moment

it seems like it has started getting worse recently??

 

[3db]

hey thanks for the reply, i will try that if i come across any other speaker wire, although i dont have any spare at the moment

it seems like it has started getting worse recently??

are both tweeters buzzing?

 

[holden_stroker]

yes they are, about the same noise level out of each.

 

[3db]

yes they are, about the same noise level out of each.

Both buzzing with nothing plugged into the receiver. Get an extension chord and plug the receiver into another outlet. I just want to eliminate the wall outlet as the source. I doubt thats the problem but I just want to make sure. I'm of the impression that your receiver has a fault in it somewhere.

 

[holden_stroker]

you wouldnt beleive it.. i went and plugged in another lead... and went to turn the power off on the receiver and noticed it wasnt buzzing.. turned volume right up and none at all... weird... tried the other power point and thats fine as well..

do you think there could be interference coming from my neighbours stereo perhaps? i live in a unit and their stereo is just on the other side of my wall probabaly about 4ft from mine...??

 

[Rickster71]

There are a few possibilities concerning your outlet.
3db has certainly led you in the right direction.
You need an outlet tester, one that plugs in, and has three indicator lights.
It's under $10 at Home Depot.
It will inform you of reversed polarity, bad ground or neutral, etc.

 

[holden_stroker]

ahh ok, thanks for that, but whats home depot? i live in australia and have never heard of that place..

 

[Rickster71]

Hi Holden, you've got me on that one.
I thought they were everywhere.
Any home improvement / hardware store / electrical supply.
Below is a link to one.
http://www.globaltestsupply.com/test_equipment/AEMC_OT-1_Outlet_Tester_.cfm

 

[TLS Guy]

ahh ok, thanks for that, but whats home depot? i live in australia and have never heard of that place..

Living in Australia makes a big difference! I'm not sure of the power distribution system in the Australia but I think it is the same as the UK which is very different to the US. I know Australia is 240 volts 50 Hz, and I,m pretty sure the set up is identical to the UK.

In the US there are two phases coming in to each house and a neutral. Each phase is 110 above neutral and 220 volts between the two phases. So that is how in the US you get 110 volts to lights and outlets and 220 volts for dryers, stoves, water heaters etc.

Now in the UK, and I believe Australia, it is 240 volts and one neutral to each home. Three phases come off the generator at the plant and every third house has the same phase and the ones in between the other two phases.

Now because the voltage is so much higher, as line losses are the square of the voltage times resistance of the line, there is need for far fewer transformers. Now RF does not get passed by transformers because they are inductive and will not pass RF. So in the UK, and I think Australia, you have far more homes sharing the same electric circuit, and much more opportunity for your neighbors' dimmers fluorescent lights and motors to radiate RF into your home. Remember when a device leaks RF into the mains, all the wiring connected downstream of the last transformer is a giant transmitter antenna!

I know when I lived in the UK I had much more trouble with RF interference than in the US.

 

[holden_stroker]

ahh ok, thanks for that.. we have d1ck smith's here, thats world wide isnt it ?

i might have to look around and see what i can find..

edit: actually i think dad has one in his shed, its more like a surge protector though... looks identical with the lights and switches only you plug something in it.. uses it with all his power tools..

 

[TLS Guy]

ahh ok, thanks for that.. we have d1ck smith's here, thats world wide isnt it ?

i might have to look around and see what i can find..

edit: actually i think dad has one in his shed, its more like a surge protector though... looks identical with the lights and switches only you plug something in it.. uses it with all his power tools..

One other thing. Do you know if the manufacturers sell the same models in Australia as compared to here? The reason I ask that, is that European models are often very different. The EEC has very strict regulations about not only how much RF a device is allowed to generate, but also how susceptible a device is allowed to be to RF. We have nothing comparable here. Those regs banned a lot of US electrical good from being sold in the EEC. Do you know if Australia does has any regs about this?

 

[Rickster71]

All the basic principles are the same!
In Australia the only differences are, the voltage is higher, plug configuration looks different, and they run at 50Hz instead of 60Hz. They still use a neutral and a ground.
So, when you go to buy the outlet tester the blade config. will be different than the picture I showed.

 

[TLS Guy]

All the basic principles are the same!
In Australia the only differences are, the voltage is higher, plug configuration looks different, and they run at 50Hz instead of 60Hz. They still use a neutral and a ground.
So, when you go to buy the outlet tester the blade config. will be different than the picture I showed.

That is absolutely true. It will show 240 Volts above ground. However the big difference is that there is one phase to the house, otherwise you would have 480 Volts available in the home. Now the real point I'm trying to make is that in the US if a transformer supplied 10 homes, in the UK and Australia, the same weight of transformer and grade of cable would supply 100 homes. If it was five in the US 25 there and so on.

Now this creates much greater opportunity for RF interference. Remember RF does not get in via the mains cable. The units power supply would take care of that in short order. This form of interference penetrates high gain circuits, and is rectified and demodulated, and comes out of the speakers as audio interference. You can not eliminate it by treating the mains supply, it comes in through the "ether."

 

[Rickster71]

Remember RF does not get in via the mains cable. The units power supply would take care of that in short order. This form of interference penetrates high gain circuits, and is rectified and demodulated, and comes out of the speakers as audio interference. You can not eliminate it by treating the mains supply, it comes in through the "ether."

Assuming the problem is RF

 

[TLS Guy]

Assuming the problem is RF

In my opinion RF penetration is the only physical phenomenon that makes sense here.

 

[holden_stroker]

ok, you guys have officially lost me now..

im still fairly new to home audio equipment

 

[3db]

ok, you guys have officially lost me now..

im still fairly new to home audio equipment

RF or radio frequency as it stands for is extremely high frequency relative to audio frequency. They have an extremely short wavelength and this physical chacteristic allows it to penetrate improperlt shielded cables, power cords, household electrical wires etc. What were saying is the noise you are hearing is a direct result of rf interference. What you might be able to do to get around this is buy a power line conditioner. You plug the conditioner into the outlet and your equipment gets plugged into the power conditioner. It offers filter against rf an other power nasties.

 

[TLS Guy]

RF or radio frequency as it stands for is extremely high frequency relative to audio frequency. They have an extremely short wavelength and this physical chacteristic allows it to penetrate improperlt shielded cables, power cords, household electrical wires etc. What were saying is the noise you are hearing is a direct result of rf interference. What you might be able to do to get around this is buy a power line conditioner. You plug the conditioner into the outlet and your equipment gets plugged into the power conditioner. It offers filter against rf an other power nasties.

The whole problem with RF interference though, is that y, just like a radio or TV transmitter. You can't eliminate it with a power conditioner. RF can not get through the equipment's transformers. The problem is devices like dimmers radiate RF back into the mains cable. It can be your neighbors dimmers and motors too. Any one on the same secondary of the nearest transformer as you, can radiate RF interference into your home. The mains cable then becomes a transmitter through the air. Your equipment receives this as radio waves through the air, just like you radio set does. You have to go into a different mode altogether to deal with RF. You have to think way beyond power conditioners. To stop RF with a power conditioner, it would have to be right were the supply comes into your house, and big enough to handle your whole house current.

You have to keep speaker cables, which are so often the entry point for radio waves from being near power cables, and not having them run parallel with mains cables if possible.

Make sure screens are in good condition. An oxidized RCA jack can be a source of penetration, as the oxide layer can act as a semiconductor, and start the rectification of radio waves at the connector. Sometimes changing the physical orientation of an amp preamp or receiver makes a difference as it can reduce the pick up by the part receiving the interference. This is just like rotating an antenna to receive a radio stations signal better.

Radio frequency interference is a tough problem. He is in Australia, that uses a higher voltage grid. He will be sharing his electric circuit with far more people than in the US, as I explained previously.