psu issue

[Damaster]

I have a pcp&c 475w power supply. Now, it comes with a fan that generates 48db. That sux. The rest of the rig will be WC but I am wondering if I should:

a) get rid of the fan completely
b) put an ultra-quiet(obviously low CFM) fan on
c) set up some kind of PSU waterblock

Any hints? what is the bare minimum airflow this kind of PSU should have?

ALSO:

has anyone had experience making a 15K rpm hard drive shut up and keeping it cool at the same time?
(I saw the foam with the waterblock thing on this site already, so don't tell me about that)

Thanks for all the help... I love you guys

[FRAGN'STIEN]

I have an FMI PSU with a loud external 80mm that I plug into my CPU fan header(for some reason I cant get the MOBO to boot with fan detection off in BIOS go figure) and I'm thinking of switching to a low flow panaflo myself. My 2 120mm on my rad are running on 7v and are virtually silent so the PSU is the only thing making noise

[Brad]

the psu does need a lot of flow through it if you are running it at it's potential, but for most systems you won't need anything that loud. try running a 120mm on top of the psu, and an 80mm on the front, both blowing in and at whatever speed you can put up with. That will surely provide enough airflow

[bigben2k]

The PSU needs a fan, always, so don't remove it! (otherwise, it'll still work, but as soon as you put too big a load on it, it will fry).

I wouldn't bother with a WB in the PSU. Just use a low cfm fan, and you'll be a happy camper.

About the HD: the reason that it is noisy, is because of the vibration that it generates. The reason that it's annoying to you, could be many.

The first thing that you have to realize, is that the HD will make that noise no matter what. The second, is that this vibration actually spreads throughout your case, making it a huge resonating box.

So, do you want to limit the vibration from spreading, or do you want to shut the whole thing up?

Try running the hard drive while it's NOT mounted to your case. If that's an acceptable noise level, then just use some rubber mounts.

If it's not an acceptable noise level, then get a 5 1/4 bay adapter, and we'll take it from there.

[gmat]

I would tend to say otherwise
1 - concerning the PSU:
* there are FANLESS psu's out there. You must cash out the big bucks, but compared to enermax prices it's not too much. Just beware, they're ATX but they wont fit in many cases without some modding.
* if you want to keep your overpriced but beloved fanned PSU and still get rid of fans, because that whispering noise is bothering you (and youre not alone), watercool it. Use a straight block and mod the mosfets so you take them out with thick wires. Then put them on top of the waterblock which will replace stock heatsinks (you'll have to mod the WB somehow for this - add it some 'legs'). Just keep the water connections sticking out of the PSU and youre safe.

2 - a 15000rpm needs active cooling even under normal conditions. To eliminate noise you must:
* cut the noise by wrapping it in foam
* dampen the vibration between the HD and your case, with rubber bands for ex.
* this is possible only with some 5.1/4" adapter.
If you do this it will overheat and certainly fail. Since it *must* be totally wrapped up to be silenced, the only solution is still watercooling. Again a straight block (such as GPU blocks) will be enough.
Someone pointed me that D-Tek makes a fine HD waterblock as well.

Good luck

[bigben2k]

I'm sure that there are fanless PSUs out there, but because of the MOSFETs, they must have some kind of airflow. So if you don't have a PSU with a fan, then you are relying on the ventilation from within the case to keep it cool. (EDIT: unless it's an expensive PS designed that way)

If this PSU is indeed rated to 475 Watts, it will certainly require some ventilation. (EDIT: unless it's an expensive one designed that way)

Think about it this way: there's a reason why ATX PSUs have at least one fan now... Some even have three! (EDIT: some really don't have any, but cost more)


A 15'000 RPM HD does NOT require active cooling (i.e. Pelt), but does require normal case ventilation. a Seagate Cheetah's operating temperature will reach 55C. THIS IS NORMAL. (EDIT: requires ventilation such as is found in a server, since these are server drives)

So if you are not happy with simple rubber mounts, then go ahead and wrap it up in foam, and then you can incorporate a HD waterBlock. Just make sure that it cools the right side of the HD.

[DigitalChaos]

i too have the pcp&c 475... that fan sucks!! but notice how hot the air comming out is? mine was running a xp2100, hard drive, and a cd drive... this is a very small load, but i found the air comming out to be quite warm. nothing super warm, maybe 50-60 C would be my best guess

is yours like this too?

im planning on cutting a hole in the top and putting a 120mm in there... but the way the heatsink looks, i dont think it will do much the way the heatsink is designed. i may just end up water cooling it with the spare 2"x2"x1/2" copper blocks i have laying around. hopefully it doesnt have 2 heatsinks like most powersupplies, cause i only wanna use one block.


as for removing the mosfets.. i wouldnt do that. i would just drop a water block or 2 on a flat part of the heatsink.

[DigitalChaos]

another option i just thought of would be to take the metal casing off... then put it behind my rad, the air comming out of the rad should be able to cool the thing off just fine.

[bigben2k]

DC, removing the PSU top, and sitting it through the rad, is the best idea I've heard yet!

I like the idea of installing a WB on the heatsinks of the MOSFETs, I'd even consider screwing the MOSFETs right into a WB, or even simpler, epoxying them.

Now I wonder... I haven't seen the size of those heatsinks, can anyone post a pic?

***
Warning to all: if you're going to mod your PSU, be aware that even though it's not plugged in, there still can be dangerous voltages in it. If you don't know what you're doing, don't even open it.
***

Make your mama proud: live to see another day.

[DigitalChaos]

well i havent opened mine up completely... i just know that to cool the heatsinks down... you gotta pull air from back to front (or vice versa... if you try to cool from the top... it would be like putting a fan blowing on a single fin of a heatsink:

heatsink fan
||||||||||| < / \
||||||||||| < \ /


air would simply be hittin a fin... and not going through all the fins

[gmat]

bigben: it seems you're uninformed. Several high quality + high power fanless PSU's exist out there.
1st there are the ones you can find in HW labs. Those are the hugely expensive and bulky ones, and we dont need the power of those (count it in KW). Needless to say, no fan in those.
2nd there are some ppl selling ATX 300+ W psu's which are fanless and *totally* closed (that means need NO airflow). I found one last week for $185. The form factor needs some case modding but thats nothing if your case is well designed (or if like me you've got a cube).
3rd MOSFETs dont produce any heat or very little if the PSU is designed accordingly (which is more expensive though). Guess what those fanless PSU's are designed that way.
Usual ATX PSU's produce lots of heat because they are *switched*. There's another thread on this forum where i explain thouroughly the differences with other PSUs.
4th I have several Ultra160 drives. All heat up to 70°C and more if left alone in a closed case.
5th Fan cooling is active cooling. Convection / heatsink cooling is passive cooling.

DigitalChaos:
Doesnt hurt to 'extend' the mosfets connections so they can be layed down on a WB. Other ppl (including the famous BladeRunner) did it with full success.
Just make sure you're good at soldering and use good quality / good diameter wire.

[DigitalChaos]

as for mosfet extension... i would guess that the longer wire would cause issues because of the slightly higher resistance you are giving them... PCP&C psus are very tightly regulated.. and you wouldnt wanna waste this

[DigitalChaos]

i just got my new DigitalCam... as soon as i get my damn 10 page sociology paper done.. ill take some pics of the inside of my pcp&c 475


hopefully i will have something this weekend... if the heatsinks look right... im gonna want to water cool them... if not.. ill use a large fan or something.

[bigben2k]

Now see what happens when I haven't had my coffee Yes, active cooling includes a fan and heatsink.

And Yes, there are completely closed PSUs out there (some only have vents), they don't need much/any ventilation, because they use higher rated components that just don't get hot at all. More expensive, but cool (pun intended). I have yet to see one for a PC, but have used several in labs. It must be cheaper to slap a 5$ fan in a PSU than to upgrade the whole circuit, so I guess that's why most of us have these hot supplies (no pun intended).

FYI, I've seen a 250W supply where the fan died, and it ran just fine. (but it had two brown spots on top )

What I know about the 15krpm HDs is that they are server drives, which implies that it will be well ventilated. (so I wasn't completely asleep!). I have no doubt that yours reaches 70C, but I also have no doubt that this is normal. Now if someone encases the thing in foam... that could become a problem.

You are right about extending the MOSFETs though, and it is a good idea. It would certainly work quite well, and not cause any problems, as long as (like you said) the lead extensions are thick enough.

I've also got to figure out how to slap together an inexpensive (but variable) PS for 2 * 226W Pelts, and a small (?!?) 80W one, at 12V. Any suggestions? I'd rather build it myself than slap a bunch of PSUs together...

I'll search for your article.

[gmat]

Take a look at BladeRunner's site and see by yourself, with good wires it wont cause any problem. Those switched PSUs are *not* tightly regulated. It's the exact opposite -> mosefts are that hot because they're given totally out of range voltages (due to the switching loop just before them).
So if you *need* to extend them it's ok. - just make sure your solders are good (theyre usually the weak spots) or they'll melt / oxyde under heavy load on the 12v.

And keep us informed Post photos of your watercooled PSU !!

[DigitalChaos]

Originally posted by gmat
Take a look at BladeRunner's site and see by yourself, with good wires it wont cause any problem. Those switched PSUs are *not* tightly regulated.

bladerunners psu was an enermax which has crappy regulation

pcp&c psus are MUCH more regulated....

i can see mosfet extensions on an enermax or other cheap psu... but not a pcp&c

[gmat]

Please explain "much more" regulated... If it's a switched PSU, it's switched, thats all... That means feeding the mosfets with a positive half-sine.
Hearing from you, the mosfets (=regulators) quality is better in pcp&c units, and extending them wont change anything for the signal quality. Remember, put *good* wire (>1mm, oxygen-free copper, thick insulation) to sustain the heavy currents and *good* solders for the same reason. The only problems you could get is from too thin wires or poor solders - and that would be wire burn-up.
In any way, it will certainly *not* throw off your regulation. The resistance of a wire is less than 1 ohm. Mosfets are surrounded by far heavier resistances and smoothing capacitors - 1 ohm is a drop in the ocean.
Putting wires is critical in HF or RF circuitry where EMI and small variations in resistance can produce bad results. A PSU is in no way a RF or HF part...

On the other hand If you succeed at sitting the WB over stock heatsinks - and if it's efficient enough - you've won some time and effort...

[DigitalChaos]

well... to actually justify what im saying.. i need to know where EXACTLY the mosfets are in the circuit.

what exactly are the outputting? are the rails that your computer gets comming straight from the mosfets?

pcp&c specs their psus output voltage to stay within 1-3% (not 100% sure on that.. but i know its under 5%)

while all others are within 5-10%

[gmat]

Originally posted by DigitalChaos
-snip-
what exactly are the outputting? are the rails that your computer gets comming straight from the mosfets?

-snip-

Certainly not. The output of a regulator is somewhat hashed and reflects the common supply at a smaller scale, usually within 5% (depending on the mosfet quality/price).
When setting up a PSU one puts a R+C (resistor+capacitor) behind to 'smooth' the signal some more, and mainly to prevent power spikes at switch on/off. Usually the R is way over 1Kohm so adding a <1ohm wire wont change anything to this. Besides a R+C will not change the total voltage...
And i suspect your very PSU has this R+C for quality reasons.

[bigben2k]

5% is very standard in most circuits.

MOSFET do get an input, but it's not exactly a positive half-sine. I seem to remember (from theory) that some of those big caps are there to partly fill those voltage drops (to 0V) at 120 Hz. (60 Hx * 2)

The MOSFET is actually there to remove the 120 Hz "ripple" in an otherwise DC signal, and to level the output to selected voltages.

As most components, there is a 5% margin of error and so, the output may vary, within operational characteristics (i.e. the load), by that margin.

Of course if you use higher rated components (i.e. higher load), then your load would fluctuate through a larger operational characteristic, hence reducing the margin of error (and the heat, as a bonus). Alternatively, you can use better quality components, with tighter tolerances.

The R+C is actually a filter. (Correct me if I'm wrong here gmat, 'cause it's still early!). The combination can be calculated to filter out a specific frequency range. It is very commonly used in speakers, in the form of a cross-over, to separate the low frequency signals from the high-frequency signals, in order for the woffer/tweeter to get its rightful part of a sound.

I'll have to read up on switched supplies, because I haven't dealt with them in 10 years...

[DigitalChaos]

ok so mosfets DO control the voltae comming out... the caps sitting there simply smooth out ripples... therefore the mosfets are the main part of the voltage regulation.

below you will see why you would want to keep the tight regulation of your PCP&C, but wouldnt think twice about doing it to an enermax.




PCP&C (Turbo 475):

3.3V 1%
+5V 1%
+12V 1%
-5V 5%
-12V 5%


Enermax (EG465P-VE FCA):
3.3V 4%
+5V 5%
+12V 5%
-5V 10%
-12V 10%

[jag_e_fattig]

Originally posted by gmat
Take a look at BladeRunner's site and see by yourself, with good wires it wont cause any problem. Those switched PSUs are *not* tightly regulated.

that's the guy who did a 100% wc:d comp. right? where's his site, i've been looking for it...

[DigitalChaos]

PCP&C turbocool 475
shot with the fan taken out.. you can see the main cooling is the aluminum, but they also put the small copper heatsinks on the backside to add better cooling... these wouldnt need to be cooled if you were using water... perhaps water on the 2 main aluminum heatsinks.. with a low cfm fan still pulling the excess ambient.

[DigitalChaos]

PCP&C turbocool 475
top shot of the psu... looks a bit cluttered for block mounting.
i would say that there is some room under the right aluminum heatsink.. but the left one you would have to attach a block to the inner side... or attach a block to the end (the side that faces you in the previous post)

[Cyco-Dude]

remove the heatsinks compleatly. attach the MOSFETS directly to the waterblock. thats how bladerunner did it.

bladerunners site, ZERO FAN ZONE.