background noise - normal or not?

acalex

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Hi guys,

as you know already, I am starting to move my first steps in the hi-fi world.

Tonight I was listening to some MP3 (low volume) and I noticed some background noise. I then stopped the music and put my ear next to the speaker...still the noise was there, is that normal or not? Do you hear any noise in your system? Where this noise is generated from?

I guess the fact of keeping the speaker cables next to the mains cables doesn't help...is there any way to reduce the noise?

Thanks for all information provided...I am reading so much stuff!
 

dannycanham

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Out of the speakers none. The Kandy has a slight internal hum.

I doubt it has anything to do with cable closeness.

Does it hum equally with rdac on and off? If so you can discount that.

Does it hum on all inputs? If so you can discount intputs.

Does it hum at the same level no matter how loud the volume is or does the hum change with the volume control?

Do both speakers make the noise?
 
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Anonymous

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I have been messing around with my system trying to figure out what is causing the hum / hiss. I have my amp on by itself no source and can still hear a faint hiss. It used to hum a little but after unplugging everything this has gone.
 

oldric_naubhoff

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the hum indicates some grounding problems. try to find out which of the components is responsible for the hum and connect it to a different electric spur.

there's nothing to do with the hiss, unfortunately. every electric device generates some level of electric noise which can be louder or quieter. if you want the hiss to disappear get yourself some quieter amp.
 

acalex

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Thanks a lot guys, first of all, what's the difference betwen hum and his? Cz I hear the noise like the classic shhhh in background (like air flowing). Both speakers...and I tried to increase the volume level...the noise increases but just a little bit...my listening level is around 1/1.5 out of 10...I went upo to almost 5 and the noise slightly incresed only...

Please let me know if there is any test I should do or any rule I should follow when I set up my system in terms of placement, cables, closeness to other electronic equipmen (I have a low table and on top there is telephone, router, wireless printer and fixed pc...on the bottom level there is the ampli alone). The DAC is placed on top of the PC case...

First of all, what are the main sources of noise? Is there any website or magazine I can read to ener more into technical details about this subject? I am myself an engineer so I quite enjoy technical stuff!
Thanks again
 

steve_1979

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Hiss is high frequency. Hum is lower frequency.

As suggested above the hiss you hear could be caused by any one (or more) of several factors. It might be that your equipment isn't grounded correctly. It could just be that you have an amplifier that hums (some do). It might be caused by electro-magnetic interference coming from some nearby electrical equiptment. You might even be getting interference coming through the mains plug from electrical equiptment in another room of your house.

First of all I'd suggest you unplug the DAC from the amp and see if the hum goes away. Try changing the input setting to another source on the amp to see if this has any effect. Try plugging the amp into different wall sockets too. Also try unplugging all of the other electrical equiptment in you room.

BTW. My AVI system is completely silent when there's no music playing.
 

acalex

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steve_1979 said:
Hiss is high frequency. Hum is lower frequency.

As suggested above the hiss you hear could be caused by any one (or more) of several factors. It might be that your equipment isn't grounded correctly. It could just be that you have an amplifier that hums (some do). It might be caused by electro-magnetic interference coming from some nearby electrical equiptment. You might even be getting interference coming through the mains plug from electrical equiptment in another room of your house.

First of all I'd suggest you unplug the DAC from the amp and see if the hum goes away. Also try changing the input setting to another source on the amp to see if this has any effect. Try plugging the amp into different wall sockets too.

BTW. My AVI system is completely silent when there's no music playing.

Ok, I am not sure if my system hums or hisses to be honest :)! I hear only the sound from the top part of the speaker!

Don't think it might be the main plug cz I installed two days ago mains block which have a built-in filter to reduce the noise...it might be the elctrical equipment around...I will try unplugging the DAC first to see what happens...

Thanks again
 

steve_1979

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Oh, and I've just remembered your using a USB cable to connect you PC to the DAC. There's a slight possibility that this might be transfering 'noise' from the PC to your hifi. If this is the case then using a digital optic cable would sort it.

There's a few thing to try out there. Let me know how you get on. :)
 

acalex

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steve_1979 said:
Oh, and I've just remembered your using a USB cable to connect you PC to the DAC. There's a slight possibility that this might be transfering 'noise' from the PC to your hifi. If this is the case then using a digital optic cable would sort it.

There's a few thing to try out there. Let me know how you get on. :)

OK, I will do some testing and update you, thanks a lot!!! :)

Do you use skype btw?
 

Andrew Everard

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steve_1979 said:
Hiss is high frequency. Hum is lower frequency.

Ono, ono, onomatopoeia...

M7180012.jpg
 

acalex

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steve_1979 said:
acalex said:
The DAC is placed on top of the PC case...

That might be it. Try moving the DAC and amp away from the computer.

Uff...this might be a problem! I will try to take some pics and post is somewhere or send to you via email. Is there any place where I can post? Or an email I can send the pics to?

I have 1,5mt RCA-RCA cable to connect DAC and ampli and 1.8mt USB cable to connect DAC and PC...have to live with that! :)

Plus I have 2.5mm/7mt speaker cable to my right speaker and 2.5mm/4 mt cable on my left speaker. Nothing too fancy, the seller gave me as an OK quality to start...wasn't aware at that time of cables specs...it costs 3.9 euro x meter approximatively...
 

steve_1979

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acalex said:
Uff...this might be a problem! I will try to take some pics and post is somewhere or send to you via email. Is there any place where I can post? Or an email I can send the pics to?

If you have a photobook account you can copy a 'Direct link' from there and paste it into the 'Image URL' on the 'Insert image' option on this forum to post pictures here.

acalex said:
Plus I have 2.5mm/7mt speaker cable to my right speaker and 2.5mm/4 mt cable on my left speaker. Nothing too fancy, the seller gave me as an OK quality to start...wasn't aware at that time of cables specs...it costs 3.9 euro x meter approximatively...

I wouldn't worry about changing your cables. 2.5mm is about about 10 guage (AWG) which is more than thick enough and if they cost 3.9 euros/meter they're probably very good quality too.
 

dannycanham

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I'm a bit lost. Did it still hum with the DAC off? If so it shouldn't be DAC placement.

You can also get radio frequency noise from monitors, TVs and computers through the air into the amp creating a low level noise similar to snow on TVs when not tuned in.
 

acalex

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dannycanham said:
I'm a bit lost. Did it still hum with the DAC off? If so it shouldn't be DAC placement.

You can also get radio frequency noise from monitors, TVs and computers through the air into the amp creating a low level noise similar to snow on TVs when not tuned in.

Danny, havent got the time to try yet, will do tonight and post the results here. Well, I have two 23inches monitors next to each other plus a fixed pc and a wireless printer...everything is within 1.5 mts of the amp...no TV yet...

Thanks again for following me on this, I really appreciate!
 

acalex

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OK, Did the testing,

ampli on the other wall plugged alone into the main, no inputs just speakers (Cable HAMA ProClass 2,25mm) and still there is the noise...both speakers and level is the same not dependant on volume level...
 
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Anonymous

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One of my speakers was making a hissing noise and it turned out to be some of the reisistors starting to fail in the biasing circuit of one of the mono blocks. However this hissing was not totally constant, it varied slightly, like a warbling hiss if you can imagine that.

So assuming its the amplifer guess you either need to put up with it, or have someone technical take a look.
 

acalex

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steve_1979 said:
Seems like it might just be the amplifier humming then. Maybe you should take it back to the shop where you bought it and get them to check it for you.

So I guess it's not normal having this background noise at constant level.....arghhh, need a car now to take it back...I will go to the shop first and ask the seller about that, not sure about the outcome since it's not a shop but a big chain...not sure how much these people will be knowledgeable...
 

acalex

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Ah...I am connectly the speaker cable directly to the amp withou using any connector, but just removed 1cm of insulation and plugged...does it make any difference?
 

matengawhat

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don't want to disagree with anyone on here but have always been able to hear background noise is every system I have ever owned if putting ear to speaker with nothing playing to me this is normal and have had different levels with different systems. however if you can hear it from your listening position though yes you may have problem.
 

acalex

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matengawhat said:
don't want to disagree with anyone on here but have always been able to hear background noise is every system I have ever owned if putting ear to speaker with nothing playing to me this is normal and have had different levels with different systems. however if you can hear it from your listening position though yes you may have problem.

Yes, can't hear from my listening position, not even if there is not music playing...only if I put my ear very close to the top part of the speaker (is that the tweeter, correct?)
 
acalex said:
So I guess it's not normal having this background noise at constant level.....arghhh, need a car now to take it back...I will go to the shop first and ask the seller about that, not sure about the outcome since it's not a shop but a big chain...not sure how much these people will be knowledgeable...

Some just-detectable noise from the tweeter (the upper speaker that carries the high frequencies, or the 'hiss' in this case) is possibly normal. With your ear pressed against the speaker it may well not be absolutely silent, though at normal volume level (not turned up to maximum) it should be barely audible. I'd rather you plugged something in for your test, as empty phono sockets will pick up noise. And your mains quality may cause a slight noise too. Can you plug in the DAC, leaving the DAC switched off, and try again? Select the same input that the DAC is plugged into.

I've slightly lost the plot in all the exchanges, but is this hiss audible from your normal listening position? If not, then it might be normal background noise for your amplifier.

Maybe try one in the shop, though there is usually too much ambient noise to detect such things (unless they have a sealed listening room). I've just a hunch this is nothing to worry about, as unwanted noise is rarely steady, the same on both channels, and low level. Much more common to be burbling noises (like frying something!) and/or in one channel only, or so loud it is obviously wrong.
 

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