Low Noise Adapter for Noctua fan with Splitter

Wesaboo

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Jun 18, 2014
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I recently put in 3 Noctua fans, 2x 92mm and 1x 80mm. However my motherboard only has 2 4 pin connector for fans, one of which is being used by the CPU heatsink/fan. With just one left and knowing the motherboard 4 pin connector can only support 2 fans I bought

http://www.amazon.com/Akasa-AK-CBFA06-30-Flexa-Splitter-Cable/dp/B008FZBF7E

My question is if I decided to use the included Low Noise Adapter (LNA) will I have to attach one from each fan (using 3 total) or can I get away with attaching the LNA at the motherboard connector using only 1 LNA adapter instead. Reason for this is that using 3 LNA will make cable management a nightmare lol.

Thanks, any advice would be appreciated.
 
Solution
The LNA's incorporate an inline resistor designed to step down a single fan. Using a single LNA upstream of multiple fans is something Noctua specifically recommends against, both on the website, and in the product literature. My guess is that doing it would simply reduce the effect of the stepdown per fan, but based on my respect for the quality of their work, if the Austrian engineers say don't do it, I'd be inclined to listen.
The LNA's incorporate an inline resistor designed to step down a single fan. Using a single LNA upstream of multiple fans is something Noctua specifically recommends against, both on the website, and in the product literature. My guess is that doing it would simply reduce the effect of the stepdown per fan, but based on my respect for the quality of their work, if the Austrian engineers say don't do it, I'd be inclined to listen.
 
Solution
If you already have the Akasa 3-way PWM splitter, one option depending on what case you're using and the fan locations is to use the 30cm extensions that should have come with the fans. Connect each fan to an extension, run the extensions back to a centralized location in the cable management area behind your mobo tray. Connect each extension to an LNA, then each LNA to the Akasa, then run the Akasa mobo connector back to the 4-pin header. It's not very elegant, but it works. Once it's all connected, you can bundle up all the cables in the back and secure them out of the way. As you're looking at the backside of the mobo tray, there's usually open space along the right side where you can secure all the cables where they won't interfere with the rest of your non-fan cables. If any of the fans is close enough that it doesn't need the extension to reach, you can double up the extension for a fan that's farther away. I've done this with four Noctua 120mm fans and it works fine. I have a pic of the setup somewhere- I'll post it when I find it.

A word of warning though - this all assumes that the fans are all actually PWM fans. If they are 3-pin models, they're all going to run at their max RPM regardless of settings. If that's the case, you're better off connecting them to the regular fan headers, with or without LNAs, and controlling them through bios or software.

Also, while not ideal, those fans have low enough wattage and amperage draws that you could daisy chain them with the included y-splitters and connect them directly to the 4-pin header. If you do that, I wouldn't use the LNAs at all.