Low Noise Adapters

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Low Noise Adapters

Post by comp1mp » Thu Sep 24, 2009 4:17 pm


I purchased a couple of Noctua FLX fans which come with low noise adapters.

Can I use these adapters for any other fan?

Can you please explain why one way or another? (e.g. No you cannot - something has to exist in the fan motor to correctly respond to the increased resistance of the adapter.)


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Post by frenchie » Thu Sep 24, 2009 10:25 pm

I've use those adaptors (from different Noctua fans, 92mm and 120mm) on some other fans (Scythe and Noiseblocker) and they work great. However, I'm not sure they'll work on PWM fans (the one with 4 wires).

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Post by Weldingheart » Thu Sep 24, 2009 10:40 pm

I suppose your FLX fan is NF-S12B FLX, which rated 0,1A (1,2W)?

The consideration to use these resistors is your fan's current/wattage rating must not exceed resistor's wattage to prevent the resistor to be burned/overloaded. For example if you planned to run Ultra Kaze which rated for 0.25A....

From this page:
for LNA resistor[quote]The “Ultra Low noise adapterâ€

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Post by Lt_Dan » Fri Sep 25, 2009 3:47 am

wow. i got the same problem TODAY!

can i connect it to a scythe s-flex 1200? (the 5v\7v)?

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Post by Floppy » Fri Sep 25, 2009 6:08 am

I've used the ULNA adapters with S-Flex 1200 and it's worked just fine. IMO ~ 600-700 RPM (never checked it with tachometer to see the exact speed). S-Flex 1200 has low power consumption.

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Post by Lt_Dan » Wed Sep 30, 2009 2:25 pm

i connected the ULNA to the sys_fan (scythe s-flex 1200) which for some reason starts at -4V (300rpm if the fan starts at all).
but when i get to win speedfan starts it at 710rpm (i think it's around 6v).

how come that happens

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Post by Klusu » Wed Sep 30, 2009 11:56 pm

Weldingheart wrote:...your fan's current/wattage rating must not exceed resistor's wattage...
51 ohm 1W will not be burned by 4-5W fan (You should not connect a 5W fan to 51 ohm. Connect the fan to 5V instead).

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