PC Linear Power Supply - Laptop wall wart replacement

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anthony a.

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hi, i recently bought an asus eee box which is a small form factor pc that is fed into a usb dack in my hifi rack.  unfortunately, the wall wart (switching) ps that it came with (same ones used on laptops) is giving off a lot of noise pollution on the ac line and audibile through my speakers.  i have it plugged into a balanced isolation transformer which helps a bit, but its still noisy.  im looking for suggestions on what i can replace this with no ill effects on the pc.  when i had my squeexebox and bolders linear power supply, the noise was very quiet.  im looking for something similar although at a cheaper price point.  any suggestions would be appreciated. 

p.s.  the wall wart specs are as follows:

ASUS AC/DC ADAPTOR
Model: SADP-65KB B
Input: 100v-240v --- 1.5A (50-60 Hz)
Output: 19v --- 3.42A

« Last Edit: 27 Feb 2009, 04:37 pm by anthony a. »

anthony a.

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Re: PC Linear Power Supply - Laptop wall wart replacement
« Reply #1 on: 27 Feb 2009, 04:41 pm »
after some research as well as numerous conversations with experts regarding this topic, it seems that the power supply is the culprit for the excess noise in my setup.  i did forget to mention that my setup is very sensitive to noise, being all single-ended with tube amps that feature point-to-point wiring.  the thing that puzzles me the most is that my dell inspiron laptop running off its switching power supply (ac/dc adaptor) is competely silent in my system.  both bricks (ps) are about the same size and i can't see them being much different than each other in terms of design.  so why would one be much noisier than the other?  can it have anything to do with the actual pc components (motherboard, etc)?  my dac is usb so it the integrated soundcard shouldn't make any difference whatsoever.  any help in this regard would be appreciated.

MerlinWerks

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Re: PC Linear Power Supply - Laptop wall wart replacement
« Reply #2 on: 27 Feb 2009, 05:47 pm »
the thing that puzzles me the most is that my dell inspiron laptop running off its switching power supply (ac/dc adaptor) is competely silent in my system.  both bricks (ps) are about the same size and i can't see them being much different than each other in terms of design.  so why would one be much noisier than the other?  can it have anything to do with the actual pc components (motherboard, etc)? 
Perhaps the dell has additional filtering at it's power input...

anthony a.

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Re: PC Linear Power Supply - Laptop wall wart replacement
« Reply #3 on: 28 Feb 2009, 06:33 am »
as an update, i went to future shop and bought a bunch of ac/dc power supplies with exact specs as the one that came with the pc.  after some trial and error, i found one that is dead silent.  so i guess i can forget about the linear ps afterall.  it just goes to show evn cheap $5 ac/dc adaptors are all built different.  im glad i tried out a few since others were better than the stock one, but not dead silent.  i can now enjoy my system after making all these changes. :hyper:

thanks for the response merlin, you gave me the push to try other ones and so i saved big $$$.

anthony a.

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Re: PC Linear Power Supply - Laptop wall wart replacement
« Reply #4 on: 2 Mar 2009, 04:13 am »
forgot to mention that all my front end is plugged into a blue circle balanced power transformer.  i was suggested to try a felix diy line filter in the ac/dc adaptor to further improve the cheap ps.  im thinking of having it modded since there was a lot of great feedback on the felix a while back.  i will keep this thread updated as i progress.

anthony a.

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Re: PC Linear Power Supply - Laptop wall wart replacement
« Reply #5 on: 21 Mar 2009, 01:12 am »
as an update, i've decided to mod the swps with a felix built into to.  i am just ordering out parts now so in a few weeks everything should be said and done.  i hope its worth the effort.