mcmaczek

I have a SB Live in my PC and stereo HIFI pluged to the black socket in the soud card. Before I play anything (film or mp3) I hear strange noise, like a base. I ddn`t have it, when the HIFI was pluged to another socket in PC but I read somewhere that the black one gives better sound. I have latency in BIOS set on 64 (motherboard with Via KT400 chipset), WinXP. I have also tried to change something in kxMixer but there still is some base noise when nothing plays.
Any ideas where the problem can be?
Thanks for help!

dj_stick

can you explain what the sound "sounds" like?

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mcmaczek

Maybe my English is not good enough to explain it but when I turn on my PC and the HIFI, graphic equalizer shows some low tone, which I can hear in my speakers or headphones. When I change the socket in my sound card, there is silnece, but the black socket in the SB is the correct one, wright?

Nappylady

The black one is correct.

It sounds like a ground loop to me.... Is the sound a solid tone, 50 or 60hz?

mcmaczek

Yes. Graphic equalizer shows some low sound in 63 Hz, which is getting louder when I pump up the volume, and I hear it before I play anything, but it is only when I plug HIFI to the black socket.

dj_stick

ok thats interesting… sounds like there is a ground-loop, or that the hi-fi is not grounded properly

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mcmaczek

That is strange, becouse when I plug HIFI to the green socket, next to the black one the sound disapears and spectrum analyzer shows nothing. I don`t have too many choises to plug PC to the HIFI, becouse it`s the old SONY equipment and I connected computer to the PHONO socket.
Any ideas what to do?

dj_stick

if the stereo is old… then use the green port - you won't notice much difference… but phono - not too great, as this is a far higher volume amp than line, reduce the soundcard volume to about 25%

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mcmaczek

I had no choise, but to use phono socket. In other way there was no sound. It should not sourprise that I can have such problems with the old stereo. I`ve reduced the volume in kxMixer and it still sounds better than whith the typical SB drivers
Thanks very much for help!
Greentings from Poland for everyone!!

Nappylady

If you are using the phono-in on your stereo, try running a separate piece of wire from the chassis of the computer (someplace where there is no paint, so it will make electrical contact) to the ground connection on the stereo. That could make all the difference.

mcmaczek

It is something strange, becouse when I pull the wire off the computer, spectrum analyzer shows all the frequences full, there is very noisy sound in speakers. It can`t be the problem of the wire, becouse i have the only one which is possible to use to connect stereo to the computer. I guess I have to use green socket in my SB.

TravelRec.

Hi!

It´s absolutely normal if you get such strange problems by using the phono input, cause this is a very high amplified input that picks up every noise around. Best is to try another in, if possible, Tuner or CD input. If not possible, you could create a voltage divider, that you can insert between the card and the phono input. Take 2 resistors with 47kOhms and 2 with 4,7kOms. Connect one 4,7k with ground and phono left, connect on the hot point the 47k and the free end of it is the new input. Repeat that for the right channel. Put this voltage divider in a little box (shielded). So you match the input impedance and you can use your card @ full volume. If the power is too high, increase the 47k up to 100 or 200k (dependent of your phono in).

Greetings!

TravelRec.

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Always take a look behind.

mcmaczek

Sounds very wise, what you write
My stereo is pretty old, so it also sounds not perfect , but mostly I listen to CD`s not mp3, so this sound is ok...
Thanks for help!
Martin