I got a nice Corsair HX1050 1050 watt PSU to run an upgraded cruncher. Unfortunately, this PSU has the odd characteristic that, when under small load, does not run the fan (good), but when the load ramps up to 20% or so, the fan spins like crazy and is very loud (bad). The built-in circuitry seems to want to cool itself way down, and then slow the fan down, but it gets warm again then goes through the same cycle over and over. VERY annoying.

What research I have done indicates that this is the way it was designed to work (but with a poorly implemented fan ramp-up?). Others have RMA'd the device but still have the fan noise problem with a new replacement from Corsair.

So: I am thinking I will change the fan for one that spins slower (hence less noise). What I would like to know, if anyone out there has an idea, is how many watts/amps the standard fan draws; presumably, a lower wattage fan would spin slower and make less noise. Or if anyone can give me a pointer to where I could find that out.

Yes, I know that the PSU would likely run warmer, but I would prefer that to having a P-51 taking off every so often. Anyway, my cruncher will draw about 600 watts, so overheating is unlikely.

Thanks in advance for any help!

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Yup, that's the way they've designed it to work :-(

It is possible to design PSU cooling systems to maintain a constant temperature without the crude cycling of fan speeds, but it costs a bit more than the simple that is so commonly employed.

You could try a lower displacement fan, which would shift less air per second, but you may well find that the fan controller will do just the same. Or you could look for a fan that shifts the right amount of air for your desired PSU temperature and runs off say one of the 12v output rails. But that might cause the PSU to shut down due to the system wrongly detecting a fan failure....

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

My idea was to substitute a lower capacity/RPM (lower wattage) fan for the existing one, using the same plug and connection, thus it would make less airflow, thus less noise. The fan that is in there now is pretty powerful - given the poor implementation of the temperature control circuitry, it cools the thing down too much, which causes the oscillatory behavior of the fan noise. This will take only minor soldering skills (which I have).

If I choose well I will get only one loud incident, when the fan starts up for the first time. Then, later, when the original fan would have shut off (or nearly so) and come back gangbusters as the temperature rises again, the new fan will just keep on, like most PSU fans...

I would think almost any lower capacity fan would have my desired effect of "smoothing out" the fan noise.

Does that make sense?

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Or just rewire the existing fan to the circuitry since you were planning on desoldering it anyway. Take it off the existing fan control circuitry and wire it straight to the 12V bus connections. If it still runs too fast and moves too much air, wire in a dropping resistor to run the fan at 7V. Lots of fan manufacturers provide LNA (low-noise adapters) to drop the fan speeds down to reduce their noise. Its the fan control circuitry that's causing your issues, not the fan itself.

Cheers, Keith

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Seti@Home classic workunits:20,676 CPU time:74,226 hours

A proud member of the OFA (Old Farts Association)

You could try restricting the air inlet then the fan will stay on as it won't be able to move enough air to cool it down enough to turn off

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Fan noise depends on two things, Blade design and RPMs. Cheap fans tend not to worry much about noise and if you are looking for a replacement, the place I would start looking here. Pull up the data sheets on the fans you are interested in and they should include noise ratings.

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Thanks for the link, but that table has NO 140x140x25mm fans listed. I need a similar table for just computer-oriented fans.

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Thanks for the link, but that table has NO 140x140x25mm fans listed. I need a similar table for just computer-oriented fans.

You might be in trouble if you can't make one of those fans work. Mouser is an industrial supply house and if they don't have something, it might be custom made for the manufacture.

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That's a standard case fan size. Lots of choices from many manufacturers.

Keith

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Seti@Home classic workunits:20,676 CPU time:74,226 hours

A proud member of the OFA (Old Farts Association)

Some psus use 135mm fans, supposedly cause of some patent.

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The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's

Some psus use 135mm fans, supposedly cause of some patent.

Yah, but not this one. I measured it, and it IS 140x140x25. I have a couple of these, as it turns out. I'll try to get this done by Xmas.

Does anyone have any idea what the specs for the built-in fan are? I can't get any info from Corsair.

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12V 2800RPM 140.0CFM 48.5dB

12V 2800RPM 140.0CFM 48.5dB

Most case fans are much lower RPM and CFM, so would be suitable for my using as described above. Do you also have info on how many watts/amps? And where did you get that info from?

AND: Thank you very much!

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0.70A, DC so that would be 8.4W

I googled HX1050 teardown and the first hit from jonnyguru shows a picture of a Yate Loon D14BH-12 and yateloon.com has the rest

Nicely done!

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0.70A, DC so that would be 8.4W

I googled HX1050 teardown and the first hit from jonnyguru shows a picture of a Yate Loon D14BH-12 and yateloon.com has the rest

VERY INTERESTING: If you look at the noise curve on the box in the jonnyguru review you pointed me at, it is different than the one on my box (same otherwise). Mine starts up at 20% power, goes nearly vertical to 30% power, then gradually rises to 100% power; whereas jonnygurus is flat until 50% or so, then curves gradually up to 100% power. So they changed the hardware that controls the fan by temperature to something more like one would expect.

I rechecked the curve by running a GTX 780 at full steam under Furmark (with MB, around 250 watts), and that gave the behavior of the curve on my box - sudden takeoff at 200+ watts to a high rev.

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Just my opinion - I don't like the low noise fan adapters that supply 7 volts to the fans. Most I have come across achieve this by connecting the fan between the 12V and 5V rails of the power supply. Imagine what would happen if a short circuit occurred in the fan or wiring. Better solution as mentioned above is a lower capacity fan.

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it would be nice if you could change the firmware on a power suply

An overclock.net thread on replacing the Yate Loon D14BH-12 fan from AX1200 seems to have some useful info.

                                                                   Joe

An overclock.net thread on replacing the Yate Loon D14BH-12 fan from AX1200 seems to have some useful info.

                                                                   Joe

Thanks for the link, Joe. I'll have to take the HX1050 apart to see if the fan in there is wired like the one in the AX1200.

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