Its independent of volume and on headphones. Yes, its general whining
stuff, and does change with processor load, and drive access as far as I
can hear. I have moved some leads about and its less now, but still audible.
Obviously the psu is a heap of junk. If I could see I'd go in and put
capacitors all over the place!

Brian

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"Arny Krueger" wrote in message
...
"Brian Gaff" wrote in message
om

I had to put a new psu in a machine over the Christmas,
and now notice the bog standard Soundblaster live card
seems to be outputting a kind of gurgling whine which
varies and kind of sounds likt e sort of low level

Two probable causes:

(1) Bad grounding of the buses on the system board.

(2) Bus domination. You need to follow up and find out what is changing
that correlates with the noise. One possible such source would be the hard
drive or the mouse. Problems that track the mouse trace back to the video
card. Problems with bus domination by hard drive controllers and video
cards can sometimes be addressed via BIOS and driver parameters.

If grounding is the problem, then there is a possibility that floating the
analog audio output of the audio interface might help. To evaluate this
see how the card sounds with just headphones plugged into it.

"Brian Gaff" wrote in message
m
Its independent of volume and on headphones. Yes, its
general whining stuff, and does change with processor
load, and drive access as far as I can hear. I have moved
some leads about and its less now, but still audible.
Obviously the psu is a heap of junk. If I could see I'd
go in and put capacitors all over the place!

I agree that the PSU seems to be behaving very poorly. Probably something
wrong with how it is grounded externally, or the layout of the board(s)
inside.

Bypassing the various lead pairs might help. Or, there might be some
place(s) where two grounds were doubled up on 1 wire.

Also check the connectors. Some have 2 or more ground wires (usually black).
One or more might not be making a good connection. Molex connectors of that
era are not so hot.

On 11/01/2010 15:26, Brian Gaff wrote:
Its independent of volume and on headphones. Yes, its general whining
stuff, and does change with processor load, and drive access as far as I
can hear. I have moved some leads about and its less now, but still audible.
Obviously the psu is a heap of junk. If I could see I'd go in and put
capacitors all over the place!

It's also many other things, EMC related. If you could get done some of
the following it may help.

Place that soundcard far away from the video card, ensure the whole
length of it's backplate is well in contact with the backplane. The
small audio wire that runs between the sound card and a CDROM drive
should be one that is screened, or frankly you could disconnect it.

Also, the motherboard should be grounded at as many screw hold points as
provided. Though there is still a trend to use plastic spaces and fibre
washers to avoid incidents of nearby PCB pads shorting. So whatever.

Or the audio mixer of the card might have input sliders active, I've
come across one chipset that had a live microphone (karaoke) input
feeding into the audio playback bus!

Talking of microphones, what happens if you disconnect that cable? The
screen of that cable might be picking up hash from video circuitry, and
even though inactive might still be feeding the mush back in.

Ultimately, I'd go for using S/PDIF and an external DAC as already
covered here. Mine's a Sony MiniDisc home deck purposely stuck on
record-pause input monitor. Or, an Audio Alchemy Dac-In-the-Box DAC that
I must get around to fixing its power supply. *That* is noisy...

--
Adrian C

Adrian C wrote:
On 11/01/2010 15:26, Brian Gaff wrote:
Its independent of volume and on headphones. Yes, its general whining
stuff, and does change with processor load, and drive access as far as I
can hear. I have moved some leads about and its less now, but still
audible.
Obviously the psu is a heap of junk. If I could see I'd go in and put
capacitors all over the place!

It's also many other things, EMC related. If you could get done some of
the following it may help.


Yeah but the point is it only happened after he installed a new psu so the
problem is probably an el cheapo psu...we've discussed the limitations of very
cheap psu's ad nauseum in uk.comp.homebuilt and I suspect this is another of
them.
--
Bill Coombes

On 11/01/2010 16:20, bcoombes wrote:
Yeah but the point is it only happened after he installed a new psu so
the problem is probably an el cheapo psu...we've discussed the
limitations of very cheap psu's ad nauseum in uk.comp.homebuilt and I
suspect this is another of them.

Er, whoops. :-)

--
Adrian C

On Mon, 11 Jan 2010 16:20:29 +0000, bcoombes bcoombes@orangedotnet
wrote:

Yeah but the point is it only happened after he installed a new psu so the
problem is probably an el cheapo psu...we've discussed the limitations of very
cheap psu's ad nauseum in uk.comp.homebuilt and I suspect this is another of
them.

Still worth checking everything else though. When the computer box
was pulled out for psu transplant SOMETHING may have been re-connected
differently - maybe a cable that was realised to be redundant? That
may have been the very one that stabilised the grounding system!

Laurence Payne wrote:
On Mon, 11 Jan 2010 16:20:29 +0000, bcoombes bcoombes@orangedotnet
wrote:

Yeah but the point is it only happened after he installed a new psu so the
problem is probably an el cheapo psu...we've discussed the limitations of very
cheap psu's ad nauseum in uk.comp.homebuilt and I suspect this is another of
them.

Still worth checking everything else though. When the computer box
was pulled out for psu transplant SOMETHING may have been re-connected
differently - maybe a cable that was realised to be redundant? That
may have been the very one that stabilised the grounding system!

You are absolutely right in that respect but I'd still replace the psu with
something decent first.

--
Bill Coombes

Hi, you are indeed right, its one of those times when the fact that it does
what it says on the tin, is not enough. If I put a portable radio on medium
wave on a clear channel, when I switch the machine on, the same or similar
whining gurgling is heard. Other machines here have little radiation at all.


Oh well, I have another one here somewhere!

Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"bcoombes" bcoombes@orangedotnet wrote in message
o.uk...
Laurence Payne wrote:
On Mon, 11 Jan 2010 16:20:29 +0000, bcoombes bcoombes@orangedotnet
wrote:

Yeah but the point is it only happened after he installed a new psu so
the problem is probably an el cheapo psu...we've discussed the
limitations of very cheap psu's ad nauseum in uk.comp.homebuilt and I
suspect this is another of them.

Still worth checking everything else though. When the computer box
was pulled out for psu transplant SOMETHING may have been re-connected
differently - maybe a cable that was realised to be redundant? That
may have been the very one that stabilised the grounding system!

You are absolutely right in that respect but I'd still replace the psu
with something decent first.

--
Bill Coombes

Brian Gaff wrote:
Hi, you are indeed right, its one of those times when the fact that it does
what it says on the tin, is not enough. If I put a portable radio on medium
wave on a clear channel, when I switch the machine on, the same or similar
whining gurgling is heard. Other machines here have little radiation at all.


Oh well, I have another one here somewhere!

Brian


Yeah I've heard that the Iranians jam BBC radio simply by powering up a 1000 low
end Chinese PSU's.

--
Bill Coombes