New method to greatly reduce noise from PSUs (No WCing :D)

PSUs: The source of DC power for all components in the PC & often a big noise source.

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Qwertyiopisme
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New method to greatly reduce noise from PSUs (No WCing :D)

Post by Qwertyiopisme » Sat Jul 24, 2004 7:35 am

Soo.. One day after my PSU had been annoying me as usual (HEC-300LR-PT, w. fan mod), I thought of a good new idea of how to quiet it without buying a new one, this was after i thought about how inefficient a normal PSU is at getting heat away from the FETs (it does a relatively good job of removing heat from other components, like caps and stuff, but awful at removing heat from FETs, the design looks like something from the AT-era, and I'm surprised that no big company has already implemented this and sold it as a super-quiet alternative (other than passive ones which seem to be more marketing ploy than anything else (and very pricey too), as they are prone to overheating and require a case fan, which kind of negates the passiveness of the whole thing, it also makes the FETs IMO too hot)).

Anyway, my idea kind of stems from the WC solution someone (IIRC someone from Russia) where he would de-solder the FETs and attach them to a WB. I considered that for a while but decided not to do a WC setup, the risk of a mica shim breaking and giving the top of my 2500+ die wall power (:shock:) was a bit... off-putting..

So I thought for a while, and thought, what if I which the WB for an air cooled alternative, some sort of HSF assembly that has a thick, large base (and should be cheap). The Arctic Cooling TC 2 seemed to fit the bill, with a 44x44mm base, that should provide ample room for the FETs.

I also didn't want to run the risk that I could fry my PSU by having two mica shims break, where one FET would be from the larger heatsink in my PSU and one from the smaller heatsink, so the safest thing to do would be to have two of them, one with all the larger heatsink's FETs and one with the smaller heatsink's FETs.

As of yet I haven't done anything but planning, but I feel that if I post this here other people can give their ideas (and any obvious bugs can be worked out) and then this may be actually done IRL.

(Who knows, this may be the thing that starts big companies redesigning their PSU's to be like this :D )

Some people her will also say that this won't do any good beacuse the FETs will still only get as much fresh air coming in, which is true, however the temperature of the FETs will be connected to a system with a much, much better *C/W value, meaning that they won't *need* as much airflow.

Also, for a standard 300W PSU with an efficiency of.. say.. 65% (just to be safe) and a load of.. 200 watts, that would mean roughly 70Watts distrubuted over 2 heasinks, and over a much larger area on the HSF's base, whcih means that the fans won't nessecerely be spinnign very quickly (of course if this is effective the AC HSF's can be replaced for some SLK-800's for instance, and with two L1a's at a suitable voltage)



Edit: Just for clarification:

- The 80mm fan will still be in the PSU, although at a low voltage
- The brown line in the image is a wooed (or other suitable material) barrier making this a 5.25" bay PSU duct
- There is approximatly 37mm of clearance on either side of the AC HSFs (roughly 80mm if it was pressed to one side) and roughly 15mm on the top and bottom which means that the rear fan *will* still get fresh air (and that there is more surface area in the intake than the area of the rear fan, which means it wont get all too strangled), especially if placed like this:

|_______|
|xxxxxxx|
|--_____|
|--|-------|
|--|_____|
|---OO---|
|_______|
----------
----------
xxxx-----
xxxx-----
xxxx-----
----------
----------
-----xxxx
-----xxxx
-----xxxx
----------
----------
//////////
\\\\\\\\\\


Where the ///\\\ is the air filter, ---- air, xxx fan, and the oo and theh box are components inside the PSU




Comments and Crit would be needless to say, very appreciated. :D
Last edited by Qwertyiopisme on Sat Jul 24, 2004 9:10 am, edited 6 times in total.
[size=75][color=purple][list=1]
[*]3800+ (X2), 2gb ram, 1390Gb storage, complete homemade watercooling
[*]3000+ (Winchester), 1gb ram, 120Gb storage, home-made chassis[/list][/color][/size]

Qwertyiopisme
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Joined: Tue Nov 11, 2003 6:48 am
Location: Gothenburg, Sweden
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Post by Qwertyiopisme » Sat Jul 24, 2004 7:47 am

Um.. I made a sketch of it in flash, it's here

http://www.peacefulpc.com/spcr/sketch.png - Thanks to PeacefulPC for hosting it :D
Last edited by Qwertyiopisme on Sat Jul 24, 2004 8:56 am, edited 2 times in total.
[size=75][color=purple][list=1]
[*]3800+ (X2), 2gb ram, 1390Gb storage, complete homemade watercooling
[*]3000+ (Winchester), 1gb ram, 120Gb storage, home-made chassis[/list][/color][/size]

peteamer
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Post by peteamer » Sat Jul 24, 2004 8:53 am

Qwertyiopisme, Sounds like a good idea so far to me...

Do keep us updated.



Pete

P.S. You could use www.photobucket.com for image/pic hosting.
Last edited by peteamer on Sat Jul 24, 2004 8:55 am, edited 1 time in total.

peacefulpc
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Post by peacefulpc » Sat Jul 24, 2004 8:54 am

quiet:p4 2.4 w/ heatlane zen; papst 80mm; silentmaxx ps; seagate in smartdrive enclosure
quieter:athlon2200+ 1.35v mobile; no case fans silenx ps; spinpoint drive in smartdrive enclosure
quietest:via mII fanless; 1 gb flashdrive; no moving parts!

peteamer
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Post by peteamer » Sat Jul 24, 2004 8:56 am

Or you could wait a minute and the very nice man from peacefulpc will do it for you. :-)

greeef
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Post by greeef » Sat Jul 24, 2004 10:18 am

I've always though the best way to make a psu, although big, would be to use overrated torioidal transformers for each line and normal voltage regulators etc, just like a traditonal power supply. You'd never worry about rails dropping, and with the isolation and muffling techniques already used for things like hard drives, silencing would be easy (suspension works well for massive transformers.)

but most people want portability and space. It would be easy to leave a regular psu in the pc to transport it though.

griff

bchung
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Post by bchung » Sat Jul 24, 2004 4:52 pm

That was the first mod I had in mind when I got my Chilli pro case. Using the 1/8" Aluminum panels as heatsinks for the isolated FETs.

There is a 5V 120mm on the CPU sink inside the case and 2 slow squirrel cage fans. One squirrel cage at the top to vent the hot air at the top of the case. The other squirrel cage to vent the PSU exhaust from the small live MOSFET and coils.

The rest of the MOSFETS are isolated and attached at 4" intervals to the inside of my side panel. The extensions are not too long, but allow the panel to be placed side while the PSU is on. The panel gets warm to the touch, but no FET goes over 40C even with my with 220W peltier torture test.

I also discarded the old PSU cage. Regrounded everything and made my own enclosure from aluminum sheet with ultra-soft sorbothane as an acoustic liner. The squirrel cage is at the top of the PSU. The coils are the hottest components in the PSU. There are small ducts (made of thin sheet rubber) to direct the inlet air to the coils.

The new PSU dimensions are 5"x5"x2". I covered up the PSU exhaust port on the case and cut out the slot for the squirrel case exhaust.

larrymoencurly
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Post by larrymoencurly » Sun Jul 25, 2004 11:37 pm

How about replacing the FETs with some having lower Rs-on ratings or putting identical FETs in parallel on the same heatsink? The latter is supposed to cut the Rs-on by more than half because each FET runs cooler.

Mod-ern man
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Post by Mod-ern man » Mon Jul 26, 2004 4:41 am

bcchung, how about a couple of pics of your blower(s) setup. I am also looking at blowers for more quiet, efficient cooling.

Cheers

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