Noctua NF-A14x25 G2 PWM Sx2-PP, Dual Fan Set for Push-Pull and Side-by-Side Applications (Brown)

About this item Dedicated dual fan set with two NF-A14x25 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 as well as situations where two fans are operating side by side (280mm water cooling radiators, case intake or exhaust fans, etc.) Includes anti-vibration mounts, anti-vibration gaskets for tighter seal on radiators, 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) Product Description The NF-A14x25 G2 PWM Sx2-PP is a set of two NF-A14x25 G2 PWM square-frame 140mm fans that are offset in speed, which can be beneficial in push-pull operation as well as in situations where two fans are operating side by side, such as in case cooling applications or on 280mm water cooling radiators. When two fans are running at almost the same, constant speed in a push-pull configuration or, albeit to a lesser extent, side by side, 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-A14x25 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 leverage extra torque headroom to keep the exact desired speed even when working against significant flow resistance such as on water cooling radiators and 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. Dual fan set for push-pull and side-by-side usage Bundling two NF-A14x25 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 as well as situations where two fans are operating side by side such as on 280mm radiators or in typical case cooling applications. 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-A14x25 G2 PWM PPA NF-A14x25 G2 PWM PPB 2x NA-RC16 Low-Noise Adaptor (L.N.A.) NA-YC1 4-pin PWM splitter cable 2x NA-EC1 30cm extension cable 8x NA-AV2 anti-vibration mounts 2x NA-AVG2-LR anti-vibration gasket for water cooling radiators Fan 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-A14x25 G2 PWM NF-A14x25 G2 LS-PWM NF-A14x25r G2 PWM NF-A14x25 G2 PWM Sx2-PP NF-A14x25r G2 PWM Sx2-PP Add to Cart Add to Cart Add to Cart Add to Cart Add to Cart Customer Reviews 4.8 out of 5 stars 31 3.9 out of 5 stars 5 4.8 out of 5 stars 13 4.7 out of 5 stars 29 4.9 out of 5 stars 13 Price $39.90 $39 . 90 $39.90 $39 . 90 $39.95 $39 . 95 $76.90 $76 . 90 $76.95 $76 . 95 Connector 4-pin PWM 4-pin PWM 4-pin PWM 4-pin PWM 4-pin PWM Voltage 12 V 12 V 12 V 12 V 12 V RPM 1500 RPM 800 RPM 1500 RPM 1500 RPM 1500 RPM RPM with L.N.A. 1250 RPM 600 RPM 1250 RPM 1250 RPM 1250 RPM Acoustical Noise 24.8 dB(A) 11.4 dB(A) 24.8 dB(A) 24.8 dB(A) 24.8 dB(A) Acoustical Noise with L.N.A. 19.7 dB(A) 8.6 dB(A) 19.7 dB(A) 19.7 dB(A) 19.7 dB(A) Size 140x140x25 140x140x25 140x140x25 140x140x25 140x140x25 Colour Brown & Beige Brown & Beige Brown & Beige Brown & Beige Brown & Beige Quantity x1 x1 x1 x2 x2