Noctua NF-A14x25r G2 PWM Premium 140mm PC Cooling Fan - Ultra Quiet, Push-Pull Set of 2 (Brown) - Perfect for Gaming PC, Workstation & Server Cooling

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. 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 progressively bent forward further out. Working in tandem with the Centrifugal Turbulator hub, this design not only helps to push more air towards the outer blade areas where efficiency is higher but also assures maximum lift and near uniform loading across the entire blade span. SSO2 Bearing The NF-A14x25 G2 features the further optimised second generation of Noctua's renowned, time-tested SSO bearing. With SSO2, the rear magnet is placed closer to the axis to provide even better stabilisation, precision and durability. Ultra-tight tip clearance The NF-A14x25 G2 has a record tight tip clearance (distance between the blade tips and the inside of the frame) of only 0.7mm. This highly ambitious design sets a new benchmark for 140mm fans and helps the NF-A14x25 G2 to work more efficiently against back pressure, such as on heatsinks or radiators, by reducing leak flows through the gap between impeller and frame. Scope of delivery NF-A14x25r G2 PWM PPANF-A14x25r G2 PWM PPB2x NA-RC16 Low-Noise Adaptor (L.N.A.)NA-YC1 4-pin PWM splitter cable2x NA-EC1 30cm extension cable8x NA-AV2 anti-vibration mountsFan screws 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 and airflow demanding applications. NF-A14x25r G2 PWM NF-A14x25r G2 PWM Sx2-PP Add to Cart Add to Cart Customer Reviews 4.8 out of 5 stars 20 4.9 out of 5 stars 16 Price $53.84$53.84 $103.71$103.71 Connector 4-pin PWM 4-pin PWM Voltage 12 V 12 V RPM 1500 RPM 1500 RPM RPM with L.N.A. 1250 RPM 1250 RPM Acoustical Noise 24.8 dB(A) 24.8 dB(A) Acoustical Noise with L.N.A. 19.7 dB(A) 19.7 dB(A) Size 140x140x25 140x140x25 Colour Brown & Beige Brown & Beige Quantity x1 x2

Dedicated push-pull set (Sx2-PP) with two round-frame NF-A14x25r G2 PWM 140x25mm fans that are slightly off-set in speed (+/- ~25rpm) in order to avoid undesired acoustic interaction phenomena

State-of-the-art engineering (Progressive-Bend impeller with winglets and Centrifugal Turbulator, Flow Acceleration Channels, AAO frame) and construction (Sterrox LCP, ultra-tight tip clearance)

Ideal choice for push-pull applications on 14cm CPU coolers such as the NH-D15, NH-D15S or NH-U14S series, next-generation quiet cooling performance with unprecedented acoustic fine-tuning measures

Includes anti-vibration mounts, fan screws, Low-Noise Adaptors (LNA), extension cables and y-cable for running two fans on the same header

Trusted Noctua quality with premium-grade SSO2 bearing (MTTF > 150,000 h), safety certifications from UL and TÜV, protected against reverse polarity, over voltage and over current (short-circuits)