Noctua case fans

Casper Traberg-Larsen

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Oct 11, 2013
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I am finishing my silent pc. My case is fractal r4. I have 2 options for case fans:

Noctua A14 flx
Noctua A14 uln

I know the uln is most silent. But Will it spin around at 5V? My fans are going to run 5V. Im afraid that the uln fans are so slow that they Will not spin at only 5V?? :/
 
Solution
The Ultra Low noise version basically has the slow speed resistor adaptor built into the fan so that it runs at a slow speed even when connected to 12 volt header. The resistance drops the effective voltage down to around 7v. The FLX version with the included Ultra Low Noise adaptor will be very similar. As will the PWM version with the adaptor.

If you are actually going to connect them to a 5V power source, then you probably do not want the added resistance. At a certain point, you might as well not bother with fans if they aren't even turning.

If you have the ability to dial in your voltage to get your desired fan speed, then I would get the PWM versions and slow them down by lowering the voltage. If you don't have adjustability...
The Ultra Low noise version basically has the slow speed resistor adaptor built into the fan so that it runs at a slow speed even when connected to 12 volt header. The resistance drops the effective voltage down to around 7v. The FLX version with the included Ultra Low Noise adaptor will be very similar. As will the PWM version with the adaptor.

If you are actually going to connect them to a 5V power source, then you probably do not want the added resistance. At a certain point, you might as well not bother with fans if they aren't even turning.

If you have the ability to dial in your voltage to get your desired fan speed, then I would get the PWM versions and slow them down by lowering the voltage. If you don't have adjustability, then I would get the FLX version and use it's two included adaptors to get the speed you want. With a 12 volt source, you'll want the adaptor, but you won't know which one without trying. With a 5V source, the fans will probably start and run very slowly, but may not work with or need an adaptor.
 
Solution