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
interference you get on some weaker fm stations.
I guess the crud removal in the psu is crap, but the thing is,does anyone
do a kind of gadget you can plug the motherboard power plug into, and get
cleaner power out for the board. after all nothing else has changed, so it
has to be on the power line to the analogue bits of the card.

Brian

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"Brian Gaff" wrote in message
om...

but the thing is,does anyone do a kind of gadget you can plug the
motherboard power plug into, and get cleaner power out for the board.
after all nothing else has changed, so it has to be on the power line to
the analogue bits of the card.


I've never heard of such a thing, and very much doubt that that such a thing
is made.

David.

In article , Brian Gaff
wrote:
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
interference you get on some weaker fm stations. I guess the crud
removal in the psu is crap, but the thing is,does anyone do a kind of
gadget you can plug the motherboard power plug into, and get cleaner
power out for the board. after all nothing else has changed, so it has
to be on the power line to the analogue bits of the card.

Why not simply change to an outboard DAC like the DACMagic? That works very
well in my experience.

BTW It does not *have* to just conducted by the power line. Could be
radiated or EM coupled.

FWIW Personally I avoid using any analogue stages inside a computer as they
generally aren't designed to provide a suitable environment. Instead I
either take out optical SPDIF or USB (as for the DACMagic). Of these
optical is probably best if you have a serious interference problem, but
USB works nicely in the cases I've tried with the DACMagic.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On Mon, 11 Jan 2010 08:49:12 GMT, "Brian Gaff"
wrote:

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
interference you get on some weaker fm stations.
I guess the crud removal in the psu is crap, but the thing is,does anyone
do a kind of gadget you can plug the motherboard power plug into, and get
cleaner power out for the board. after all nothing else has changed, so it
has to be on the power line to the analogue bits of the card.

Try a different power supply. They're cheap enough, or you could
borrow one from another computer. If it sounds better, try to get a
refund on the noisy unit.

But before you do that, check the ground connection on the mains power
cable.

"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.

Hmm, that is an idea. Also of course one could leave the screenreader on the
internal card, and only have the audio you want through the drivers to the
new external card.

Hmmm
Brian

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graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Jim Lesurf" wrote in message
...
In article , Brian Gaff
wrote:
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
interference you get on some weaker fm stations. I guess the crud
removal in the psu is crap, but the thing is,does anyone do a kind of
gadget you can plug the motherboard power plug into, and get cleaner
power out for the board. after all nothing else has changed, so it has
to be on the power line to the analogue bits of the card.

Why not simply change to an outboard DAC like the DACMagic? That works
very
well in my experience.

BTW It does not *have* to just conducted by the power line. Could be
radiated or EM coupled.

FWIW Personally I avoid using any analogue stages inside a computer as
they
generally aren't designed to provide a suitable environment. Instead I
either take out optical SPDIF or USB (as for the DACMagic). Of these
optical is probably best if you have a serious interference problem, but
USB works nicely in the cases I've tried with the DACMagic.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics
http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Already done the ground thing, indeed, I have too good an earth and had to
be very careful with cable length to stop earth loop problems with
connected gear.

Well, the psu is not actually new, spare would have been a better term..
However it seems robust enough, but the fact the previous dead supply did
not have this does point to some of the switching artifacts getting into the
computer.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Laurence Payne" wrote in message
...
On Mon, 11 Jan 2010 08:49:12 GMT, "Brian Gaff"
wrote:

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
interference you get on some weaker fm stations.
I guess the crud removal in the psu is crap, but the thing is,does anyone
do a kind of gadget you can plug the motherboard power plug into, and get
cleaner power out for the board. after all nothing else has changed, so
it
has to be on the power line to the analogue bits of the card.

Try a different power supply. They're cheap enough, or you could
borrow one from another computer. If it sounds better, try to get a
refund on the noisy unit.

But before you do that, check the ground connection on the mains power
cable.

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

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"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