I have a High Power 500W HP-500-A12S PSU which has gotten quite noisy. It's some ~4 years old and has been in some 3.5 years of service I guess.

I want to do something to make it quieter, so I decided to open it up and look what kind of fan is inside.
It's a Globe Fan S120512L:


I found an old thread about it, saying it's supposed to be pretty quiet, but if it really was that's the past now.

Any thoughts about which fan could be a good replacement? I'm unsure about the rpm/amperage/wattage of the replacement fan that I should take. I believe the current fan is never reaching high rpm's but I can't read it out to know for certain.

It appears to be a standard 120x25mm fan, and the PSU doesn't seem to care about RPM, but it might check for resistance.

Disconnecting that fan and using its wires to power a new one should keep it going without trouble. Perhaps you can rig in a controller to keep the noise down.

Edit: Removed quoted message

I was hoping for some advice on what kind of fan would be most suited as a replacement. I'd like to prevent getting one that's got too much power (which would require extra work to slow it down) or one that's too slow. I was thinking about a Scythe Kama Flow 2 900rpm.

A very similar fan to yours was reviewed by SPCR in 2007 as part of a fan roundup http://www.silentpcreview.com/article739-page5.html. From this it seems that it is a 2000 rpm with a starting voltage of 4.3V. The Globe fan was also sold as the Acousti AcoustiFan AF120C, but that is no longer a current model. The closest fan I can find to this spec currently available is this one http://www.frozencpu.com/products/8402/fan-519/Noiseblocker_NB-Multiframe_M12-P_120mmx25mm_Ultra_Silent_PWM_Fan_-_1000-2000_RPM_-_12-29_dBA.html. This is a four wire PWM fan but you would only be using the two red and black wires so it would function as a 2000 rpm voltage controlled fan and its starting voltage of 4.5V is close enough.

I'd use their Slip Stream 800RPM instead. That line pushes more air per revolution, and would be tolerable to inaudible mounted in a PSU at maybe 10 or 11 volts.

I have a pair of Slip Streams on my test bench; with no obstructions between us they become audible from a foot away near 675 RPM.

take a look at this thread: http://www.silentpcreview.com/forums/viewtopic.php?f=6&t=53104

The Scythe S-Flex range is discontinued although it might still be possible to find the 1600 rpm model.

In the US, Newegg is still selling the full S Flex line. The 1400 RPM, Kama Flow 2 is a reasonable alternative.

Sleeve bearing fans like the Slip-Stream have no business being used in power supplies. The bearings tend to be short lived when used in a horizontal orientation, and there is much more work involved in changing out a PS fan than a case fan.

I believe they actually use the ever-lubricate bearing, but it's been lost in translation because it's based on the sleeve type.

It's an oil impregnated sintered bronze sleeve bearing. The simplest, cheapest bearing type used for fans. Not a fluid, dynamic bearing, and certainly not a long life bearing.

Thanks a lot for the input, all! I feel a lot more educated now.

I see that the S-Flex is slowly disappearing from the stocks of the webshops here. I don't want to spend too much to "upgrade" this power supply, so I'm looking at some affordable fans. The Noiseblocker NB-BlackSilent PRO-PL2 looks like a pretty good option.
http://www.xbitlabs.com/articles/cooler ... -1_11.html

The Kama Flow 2 looks great too in that test:
http://www.xbitlabs.com/articles/cooler ... -1_14.html

Yes, the Kama Flow 2 does look good.

The 1900 rpm version was reviewed here http://www.xbitlabs.com/articles/coolers/display/120mm-fan-roundup-2_10.html#sect0. The bearing spec certainly looks more suitable for a PSU, and at around $15 US from sources such as this http://www.frozencpu.com/products/10174/fan-653/Scythe_Kama_Flow_2_120mm_x_25mm_Fan_-_1900_RPM_w_Extra_Fluid_Dynamic_Bearing_SP1225FDB12H.html the price is very reasonable too.

So I got a Kama Flow 2 1900rpm and mounted it in my PSU. Definitely a lot quieter, without the drone of my the old fan. I'm still hearing some weird tonal noise of which I'm not sure where it's coming from, and I also obviously need to decouple the hdd because it's making my whole case resonate. Those silicon mounts in my Antec case aren't doing much, apparently.

Thanks to the PSU modding sticky it was very easy to put the replacement fan in. I just popped the little female connector off the two pins with a small flathead screwdriver and the regular 3 pin fan connector fitted on perfectly. The only thing I'm going to do is lead the yellow RPM signal wire outside and connect it to a mobo fan header, so I can monitor the rpm just for fun.

I`m a bit late to the party but it`s no biggie as I would have given pretty much the same advice as the others. Nice job connecting the rpm wire to the mobo. So, at what speed does the fan settle at idle?

Regarding the hdd: once fan noise is taken care of, one is often surprised by how audible the things can be, especially when hard mounted. Rubber grommets certainly won`t cut it, either suspending the drive or placing it on a layer of open cell foam will certainly yield much better results. Which Antec case do you have? If it`s the 300 it should be fairly easy to suspend the drives with some elastic chord. Putting the drive on foam is even easier and works great too, if you don`t plan to move the case around.

By the way, many people ask where the can source open cell foam from. The answer? At the grocery store! XL Scotch Brite FTW!