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The curse of 1u chassis: loud 40mm fans!

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i recently laid my hands on a working but empty 1u chassis that was being disposed of (a supermicro sc813m), to hold the last few drives i can add to my "backup" server. hey, can't beat *free*, right?  anyway, bought a used power board off ebay (a supermicro JBPWR2) along with an SFF-8088 to 8087 bracket, fished out a breakout cable and a fan splitter out of stash of parts, assembled the beast... tested it in a large room -- hey, not too noisy... and racked it.

 

when i turned it on again, what the...?!? it's noisier than my 2u jbod drive array! (that quantum dxi6500 i posted about some time ago)

 

i quickly found out the 40mm fans (FAN-0061L4) are rated at 44db each, so 4 times that... either i get quieter fans or i put some in-line resistors that came with noctua 120mm fans i bought for my 4u boxes (norco 4224 & rosewill 'l4500).  For the fans, i know the FAN-0100L4 would fit, though it appears to be costly to purchase in canada and only drops the noise level 10db.  another fan that could be an option (Sunon 40x40x20mm 3 pin fan #KDE1204PKVX, https://www.amazon.ca/Sunon-40x40x20mm-pin-fan-KDE1204PKVX/dp/B006ODM76C), as it is cheaper & *much* quieter, though not sure it could really be used with a at supermicro 1u chassis like mine (20mm deep instead of 28mm, 10.x CFM instead of 16.3).

 

at the moment, am leaning towards using the resistors (cheapest known solution), but i have to make sure it's safe to do so.

 

or is there another option i'm missing?

 

thanks in advance!

 

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since you said you're using a fan splitter, can you rewire it to run fans in series instead of parallel?

your bigger issue will be, getting enough air flow to maintain cooling though.

 

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@sota: (quick reply) i am using a two-way fan splitter to power two of the fans, as the JBPWR2 power board only has leads for 2 fans.

i knew the fans would then be running at full speed (the powerboard has only 3 pin leads, not 4), but my initial "does this turn on, is anything burning?" test gave me the impression the 4 fans weren't that noisy. 

 

(never test on a couch that will absorb noise)

 

 

 

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If JBPWR2 power board have PWM fan control function ( 4 wire ), then main problem should be splitter not PWM support and cause all FAN in full speed.

 

You should connect two FAN to JBPWR2  and confirm speed control work frst, then DIY connect two FAN to four FAN as below

 

Red  Blue  Yellow  Black  ( FAN 1 )                 Red  Blue  Yellow  Black  ( FAN 2) 

Red  Blue             Black  ( FAN add on )        Red  Blue             Black  ( FAN add on ) 

 

Yellow wire usually are speed detect and Blue are PWM control signal.

Edited by Benson

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@benson : the powerboard (jbpwr2) doesn't have pwm fan control capabilities.  the connectors have only 3 pins on them.

it would have been nice if the board could have controlled the fan speed, but it doesn't.

 

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