Reddit mentions of CRJ DC Power Supply for 2 x 3/4-Pin 12V Computer PC Case Fans

Hopefully amazon links are allowed here:

https://www.amazon.com/dp/B071FNN9W7/

I got 1 of those adapters (which includes a 2-fan splitter). I had extra fan splitters so I tried to go from that, split twice in a 1-2-4 fashion, but found out that it was overheating the AC unit which was rated for 1 amp, causing the fans to turn on and off repeatedly.

Surprised, I used a Kill-a-Watt to measure the actual power draw and confirmed that those 4 fans and their LEDs were definitely drawing less than 1 amp. I was annoyed about it not living up to its 1A rating, but it was still the reality, so I briefly bought a second one of those adapter sets linked above and powered 2 fans from each.

But it was further annoying me that it was now using up 2 outlets in my rack with 2 very bulky wall warts, so I ended up searching for a replacement AC adapter rated for 2 amps, and settled on this:

https://www.amazon.com/dp/B07BV8WKCP/

That's working great and handles all 4 fans. It's still connected to the 2-fan adapter included with 1 of the first items I ordered, and then splits again with my own fan splitter to power all 4 fans from one AC unit instead of 2.

PAPST is a pretty common computer fan brand - I wouldn't worry too much about the brand.

For example on Amazon you can pick up a 120mm fan for $7.49:

https://www.amazon.com/ARCTIC-F12-Standard-Configuration-possible/dp/B002KTVFTE

Then pick up a 12V transformer for $10

https://www.amazon.com/CRJ-Power-Supply-4-Pin-Computer/dp/B071FNN9W7/ref=sr_1_fkmr3_1?keywords=case+fan+12v+transformer+kit&qid=1549654218&s=Electronics&sr=1-1-fkmr3

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Under $20 and you're good to go.

I need to go clean some things up before I post some awesome photos like everyone else on here, but here's what I use in my entryway coat closet which I've retrofitted to be a server closet (while still serving as a coat closet):

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• Tripp Lite SRW12U SmartRack 12U Low-Profile Switch-Depth Wall-Mount Rack Enclosure Cabinet (I originally ordered from Amazon, but they destroyed it in shipping and then couldn't get a replacement for some time, so I used Wal-Mart after I got refunded from Amazon.)
  
• AC Infinity Vented Cantilever 1U Universal Rack Shelf, 14" Deep, for 19" equipment racks. Heavy-Duty 2.4mm Cold Rolled Steel, 60lbs Capacity - I have 2 of these in the rack so far, and love 'em!
  
• be quiet! Silent Wings 3 120mm PWM High-Speed, BL070, Cooling Fan - excellent, and as the name implies, quiet fans. The reason that I went for the PWM high-speed model is mostly for future-proofing, where I can replace the plug with something that I can tie to temperature and ramp up to high speed when I need to (bonus points if I can tie this to Z-Wave since that's what I run my house on.) For now, they run at full-speed all the time, and it's good enough.
  
• CRJ DC Power Supply for 2 x 3/4-Pin 12V Computer PC Case Fans - for powering both of the "Be Quiet!" fans
  
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  As far as air, electrical, and a ton of Ethernet goes:
  
  
• Air - I use ducts like what you'd find for bathroom exhaust fans that are the same diameter as the vent holes in the server cage. These literally sit on top of the server cage, and come through the sheetrock ceiling and vent into the attic (it's already hot up there and has vents, so I don't really care about venting the heat from the server closet into the attic.) I still need to improve this (e.g. better seals) and waiting for a friend that's *GREAT* with sheetrock to help me on this.
  
• Electrical - I ran Romex down from the attic and mounted an "Old Work" outlet box into the sheetrock, and then had an electrician connect it into my panel. I did this after buddy and I mounted the server cage so that power is directly inside of the cage. The 2 plugs are used: 1 for the server power rack, and the other for the heat exhaust fans.
  
• Ethernet - I used conduit that I cut 2 equal segments of. Like the air ducts, they sit on top of the server cage and go directly into the attic. There's a board that conveniently sits above (I think it's called a "collar tie"?) which I whittled down with a knife, and use to support the weight of the Ethernet cables that loop over it and drop straight into the conduit.
  
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  Since I've had a bitch of a time getting cable run into some of the rooms (for whatever reason, I can't just drop straight down from the ceiling since some boards cross horizontally) then I use MoCA. Specifically, Actiontec MoCA, and then the one that's in the server closet is run PoE via an adapter.

If I want to power several 140mm PC case fans, and be able to control their speed, do I need anything more than:

Power supply: https://www.amazon.com/gp/product/B071FNN9W7/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=AQ8OIL3FGVKZE

Control knob:
http://www.ebay.com/itm/RV-LAMP-DIMMER-SWITCH-12V-DC-/252811650686

Ideally I'd like to power 4 fans. could I run 4 140mm case fans off that one power supply?

Yes you can. Check this out! You can plug two 3/4 pin pc fans in as long as the Amp rating together doesn’t exceed 1A if I’m not mistaken.


CRJ DC Power Supply for 2 x 3/4-Pin 12V Computer PC Case Fans https://www.amazon.com/dp/B071FNN9W7/ref=cm_sw_r_sms_c_api_i_Y1HRDbG51FCC3

I recycled an old 12V 1A transformer. After cutting the barrel connector I soldered the female half of the fan extension cable that came with one of Noctuas (kept only the black and yellow +12V wires).

Of course you can also buy the whole thing on amazon for $11 but where's the fun!

I then connected the fans power supply to a smart power strip piloted by the ThinkPad charger so, when I shutdown or put the laptop to sleep the external fans (along with my external monitors and audio amplifier) shutdown as well.

If you are buying parts... 12v wall power supply w adapter for 3 pin fans (2) CRJ DC Power Supply for 2 x 3/4-Pin 12V Computer PC Case Fans link:https://www.amazon.com/dp/B071FNN9W7/ref=cm_sw_r_cp_apa_i_fk33Cb5JSB898 $10 no soldering or bare wires. Supports 2 fans May also be cheaper ones, or if you have a similar 12v wall power supply, may be able to get just cord adapter. Good luck

make one https://youtu.be/ITLFlFDoBG0

or

buy one https://www.amazon.com/CRJ-Power-Supply-4-Pin-Computer/dp/B071FNN9W7/ref=asc_df_B071FNN9W7/?tag=hyprod-20&linkCode=df0&hvadid=309807187084&hvpos=1o2&hvnetw=g&hvrand=9679690604448268138&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9028161&hvtargid=pla-569172351768&psc=1

Grab one of these: CRJ DC Power Supply https://www.amazon.com/dp/B071FNN9W7

Makes testing/filling trivially easy.