Like with the new NF-A14 range the new NF-SA12A also come in 3 flavors the FLX, ULN and PWM
As where the older NF-S12B is limited to just the FLX and ULN
| 3 speed settings for full flexibility (NF-S12A FLX) Providing 1200, 1050 and 900 rpm speed settings via the supplied Low-Noise and Ultra-Low-Noise Adaptors, the NF-S12A FLX (Flexibility) can be fine-tuned for superior airflow or maximum quietness. |
ULN stands for Ultra Low Noise, quote:
| 2 speed settings for maximum quietness (NF-S12A ULN) Providing 800 and 650 rpm speed settings via the supplied adaptor, the ULN (Ultra-Low-Noise) version is tailor made for serious silent enthusiasts who demand super-slow running speeds and utmost quietness of operation. |
And then we have PWM (Pulse-width modulation), which basically means a power source is turned on and off in rapid succession (pulses) and by changing their frequency slows down or speeds up the fan. PWM is also used in dimming LED lights these days as you can’t dim LEDs by ramping down the voltage… thus PWM is used. You can actually see these pulses with the naked eye if you pay close attention to the LED rear lights on cars these days and swiftly shake with your head and you’ll see what I’m on about.
More info on the PWM subject visit http://en.wikipedia.org/wiki/Pulse-width_modulation
Quote:
| Custom designed PWM IC with SCD Supporting fully automatic PWM speed control, the NF-S12A PWM uses Noctua’s novel, custom designed NE-FD1 PWM IC that integrates Smooth Commutation Drive (SCD) technology. By providing smoother torque impulses, SCD suppresses PWM switching noises and thus makes the fan quieter at low speeds |
For more info about that check out http://www.noctua.at/main.php?show=ne_fd1_pwm_ic
We can also find this chip in the latest NF-A14 series that we reviewed a while back. So apart from an extra model what more does the new series have to offer!
