Noctua Low/Ultra Low Noise Adapter Specs

So I did some testing and research and thought I'd share.
In case you didn't know the Low Noise Adapters are just inline resistors. Resistors reduce Voltage and Amperage/Current. I measured the resistance of the adapters I have with my NF-F12 and NF-A14. I'm using math to calculate the Low + Ultra specs and Voltage but it could be slightly off.

Also I wasn't sure what the minimum rpm of the NF-A14 was so I didn't know if it could go to 750rpm but I can confirm it does.


1200 rpm - no adapter                                                                      68CFM   SP 1.51mm,   19.2 dbA

1050 rpm - Low Noise Adapter             NA R10    50ohm (-1.5v)      60CFM   SP 1.18mm,   16.4 dbA

900 rpm -  Ultra Low Noise Adapter      NA R11  100ohm (-3v)         52CFM   SP   .89mm,   13.8 dbA

750 rpm - Low + Ultra Low Noise Adapter          150ohm (-4.5v)      44CFM~  SP  .60mm~  11.4 dbA~



1500 rpm - no adapter                                                                     55CFM     SP 2.61mm    22.4dbA

1200 rpm - Low Noise Adapter            NA RC6   80ohm (-2.4v)       43.7CFM  SP 1.83mm    18.6dbA

Yeah. You can make your own, actually. By changing around molex pins to run the fan at 5, 7, or 12 volts.

Ya, I was actually going to buy my own resistor and pwm connectors but it worked out with the two connected. I read about the molex mod but I didn't have the spare connector nor felt like doing it that way.

I'm assuming you determined the CFM, SP and dBA mathematically. Is that correct?

Yes that is correct. I didn't know where my graphing calculator was so I wasn't able to make a graph/formula to get exact numbers but I used the same concept with a normal calculator.