Noctua NF-A14x25r G2 PWM Sx2 PP 1500RPM 140mm Next Gen Push-Pull Fa

The NF-A14x25r G2 PWM Sx2-PP is a set of two NF-A14x25r G2 PWM round-frame 140mm fans for push-pull operation on heatsinks such as the NH-D15(S) or NH-U14S. When two fans operate in a push-pull configuration running at almost the same, constant speed, their acoustic interaction can lead to undesirable harmonic phenomena such as intermittent vibrations or periodic humming due to interference, which can be heard as beat frequencies. Therefore, the two NF-A14x25r G2 PWM fans contained in the Sx2-PP set are slightly offset in speed (±25rpm) in order to avoid such phenomena. This fine-tuning is made possible by the fans novel etaPERF motor and its NE-FD6 driver IC that achieves extremely precise speed control and, thanks to its SupraTorque feature, can leverages extra torque headroom to keep the exact desired speed even when working against significant flow resistance such as on heatsinks. With one fan running 25rpm slower (PPA) and one 25rpm faster (PPB), the overall cooling performance can be kept the same while efficiently preventing intermittent vibrations or periodic humming. Since the perception of beat frequencies can vary depending on psychoacoustic preferences, users can easily further optimise acoustics by slowing the PPA fan down a little more through PWM control or the supplied Low-Noise-Adaptor, which will result in an even smoother sound signature due to the increased offset. Push-pull set Bundling two NF-A14x25r G2 PWM fans that are speed-offset by ±25rpm in order to avoid undesired acoustic interaction phenomena, the Sx2-PP set is the ideal choice for push-pull configurations on 140mm class coolers such as the NH-D15(S) or NH-U14S. Next-generation performance Noctua’s NF-A15 is renowned as being among the best round-frame 140mm fans on the market and has received more than 100 awards and recommendations from the international press. With its further improved efficiency and novel, state-of-the-art engineering, the NF-A14x25r G2 represents another step up in performance and manufacturing. Highly optimised P/Q curve for all applications The NF-A14x25 G2’s sophisticated aerodynamic design allows for a pressure to airflow (P/Q) curve that is extremely strong in the critical mid-section. This means that the NF-A14x25 G2 is a true jack-of-all-trades with excellent performance in both static pressure demanding and airflow demanding applications. Excellent on-application acoustics While many fans produce unpleasant, high-pitched noises when installed in typical applications such as on heatsinks or radiators, the NF-A14x25 G2 has been carefully fine-tuned for optimal on-application acoustics. It produces a smooth, pleasant frequency profile and surprisingly low sound pressure levels (SPL) when working against back pressure. Progressive-Bend impeller The NF-A14x25 G2 features a unique Progressive Bend Impeller with Flow Acceleration Channels and winglets. Its nine blades are swept backwards close to the hub and