Cases with 2 120 mm or bigger fans on the back

[satanicoo]

hi peep.

i am here looking for this info:

-does anyone know of a case with 2 Large fans in the back?
i prefer larger fans than 120, but those must be rare ( if exist at all), so does anyone know of a case with 2 120 mm ones in the back?

thanks in advance.

[sn_85]

Lite-On Mid Tower ATX Case Model FS-020
http://www.newegg.com/app/Showimage....128-111-05.jpg

its the same case that comes with the swiftech qpower. lots of room and good build quality. cheap too.

[Brad]

The FS020 is the only case available this side of a large server case with 2x 120mm fan spaces at the back. There are however a number of cases out there that have just one 120mm fan at the back.

Your other option would be to buy a large server case www.servercase.com is a good place to start, and modify it yourself

[satanicoo]

the lite-on looks damn sexy, thanks

cheap too!

damn! this server ones really look cute, and spacey, maybe could be modded to 2 fans, must think about it.

server cases

[JokerCPoC]

Cheap? At $125.00 They aren't really cheap, But for the money It's the Best I've seen, Most other cases are too modded or in the Case of the Antec Sonata/Lan Boy, Too Restrictive on air flow from front to back and the Lan Boy is Just too Flimsy (1.2mm thick Aluminum, Most use 2.0mm with folded edges) for My tastes and is just about as bad as the Sonata. No I'd rather Buy the Lite-On FS020 from Newegg than buy either of those two Antec cases, Even If You can use My Favorite fan size "120mm" in them.

[Since87]

One thing to be aware of with the FS-020, is that it will obstruct the intake fan of some of the higher end PSU's.

I'm currently wrestling with what to do about this.

Remove some drive bays and drill out some rivets to remove the fan intake obstruction?

Buy a 530W Fortron supply that doesn't intake air from that direction?

Get an Antec TP and mod it so that it intakes from 'the end' rather than the bottom?

[JokerCPoC]

I was thinking about water cooling mysellf, I only need 3 more parts:

Teflon Tape,
Gemini Cool GF4 Water Block,
120vac relay kit.

That should just about do It, I just wish My Pyramid V fan controller (48watts max. capacity) would get here, It was an RMA return of a dead Pyramid II fan controller (24watts max. capacity) to Cobalt3 and It's been since May 26th that I sent It in and so far I havn't received much besides excuses from them. It seems that on startup fans will use twice their rated wattage, So 6watts becomes 12watts on startup, and I had 36watts on startup, It was still under warranty too and Cobalt3 said They would replace It.

[iggiebee]

Also at newegg.com, and to complete the setup you only need a .SparklePower 550W rated at +12V 36A, so you can add all the pelts you want later on.

I've been using a Sparkle 550W for a month now, powering a swifty + pelt (MCW462-UHT), and an Eheim 1046 (12V DC version), with no problems.

[Since87]

Originally posted by iggiebee
Also at newegg.com, and to complete the setup you only need a .SparklePower 550W rated at +12V 36A, so you can add all the pelts you want later on.

I've been using a Sparkle 550W for a month now, powering a swifty + pelt (MCW462-UHT), and an Eheim 1046 (12V DC version), with no problems.

What motherboard have you been using?

I thought the 550W Sparkle would only work with server motherboards due to its having a 24 pin ATX connector rather than the standard 20 pin.

[iggiebee]

Originally posted by Since87
What motherboard have you been using?

I am using an Asus A7S333 w/ Athlon T-bred 2100+

I thought the 550W Sparkle would only work with server motherboards due to its having a 24 pin ATX connector rather than the standard 20 pin.

If you read the specs, you will notice it says it's compatible with both AMD Athlon/P4 and Server setups. It brings an adabter for the regular ATX connection. Be prepared for extra long sets of wiring though .:shrug:

Also it is very compact, silent, and relatively low temp.

[pHaestus]

You can fit 2 120mms into the front of a Chenbro Genie with a bit of modding...

I always wanted a Liteon FS020.

[satanicoo]

I have decided to build my own Cube case, for water cooling. They are sexy, just waiting for stirling cycle motors to apear in the market...

[Seyeklopz]

162mm fans here

This case is supposed to have a 180mm fan at top and behind cpu. Could it be a typo?

This review says 4 80mm fans.

[Seyeklopz]

I found a 172x50mm fan on www.nmbtech.com. Browse their site for Distributors, Fans to buy. I have the pdf file on my http here.

Can get it with a black aluminum housing, snazzy.

[Phalanx28]

Originally posted by Since87
One thing to be aware of with the FS-020, is that it will obstruct the intake fan of some of the higher end PSU's.

I'm currently wrestling with what to do about this.

Most people just turn the PSU upside-down. Those with two fans on their PSU who are worried about the heat pocket that may be created between the unit and the top of the case choose to put a blowhole there.

I don't think I'd go that far.

Phalanx28

[jafb2000]

Originally posted by Seyeklopz
I found a 172x50mm fan on www.nmbtech.com. Browse their site for Distributors, Fans to buy. I have the pdf file on my http here.

Can get it with a black aluminum housing, snazzy.

You will not get the deep 172mm fans, nor the NMB x38mm deep
172mm fans to be particularly quiet. They are also very very hard
to get hold off in the lower-noise versions, and not cheap.

PWM can easily make them group, and undervolting whilst
working is /non-linear/. Specs for the temp-variable versions
often show the caveat - which for them is bearing noise.
o 50% 35dB(A) -- not the ~21dB(A) conservatively hoped for
o 100% 51dB(A)

Also, to feed them, they require very very open enclosures in
terms of "ease of intake". A 55mm fan of that type can create
very high suction forces, if allowed to develop into turbulence,
stall or thrust on the bearings due to inadequate intake then
the noise will be simply obnoxious. Also, the intakes must be
kept free of any major object for at least 8cfm in front of them,
otherwise again you get very considerable intake noise.

120mm is a reasonable biggest-size-to-use unless you come
up with a way of fitting 45dB(A) 254x89mm Caravels in there.
They are much quieter for the airflow, but ... A Bit Big.

Bearing rumble on a steel case without huge reinforcement
is likely to result in some interesting industrial sound effects.

You could borrow that rather high Nasa windtunnel building.
"Intel in 2050 released their new processor today, it powers
the planet's CPU needs, and its heatsink just fits in the building.
When asked about how windows 2050 performed, they were
quite confident office applications would be smartly responsive".

A 30W fan is ~1/25th of a horse-power, watch fingers :-)

[V12|V12]

I have several RoTron-Comair 172mm x 50mm DEEP and it runs at 5v without any startup problems AND it's DEAD silent. The only way you can tell it's on is to actually put your ear RIGHT next to the intake... and at 300CFM at 12v, this baby at 5v would DESTROY any puny 120 at 12v... Oh wait, I have heard those NMB's and they barely make a sound, you don't know what you're taking about, until you ACTUALLY OWN/Test the fan in person...pdf's are misleading. Bearing noise/rattle? What kind of POS fans are you talking about? I've heard and played around with 172mm NMB's, Comairs, Nidec Torins, BOxers etc... and they are INDUSTRIAL fans, not some cheap PC cooling toy. They last over decades of HARSH heat and operating conditions. The bearings are nearly impervious to dust and contaminants etc... if the pdf states 80,000hrs MTBF it WILL last at LEAST that long and londer if the load conditions are less than stated. These are professional fans, not cheap plastic toys. If you can get one of these monsterous fans, I'd surely get one and most quality made fan controllers can handle 18-20W taming one shouldn't be too hard. Good luck

[pHaestus]

No experience with the NMBs but I have used 12V and 24V Comair Rotron Patriot fans before. jafb2000 is right about them; they don't respond as well to voltage reduction as you'd expect. The 24V running at 12V is ok but there is a definite bearing noise coming from the motor. Not annoying but present. 12V at 6V same thing. I had no luck running the 24V fan at 7V btw.

And he was referring to the noise that fans make while in PWM. If you haven't run fans with PWM controllers then YOU don't know what YOU'RE talking about until YOU actually do so. Ball bearing fans can quite often develop some extremely annoying and industrial sounding noises when you adjust their power with PWM. I haven't put the Patriot on PWM yet (though that's a fine idea) but I wouldn't doubt that it does this when I think about how other beefy fans (Vantec Tornados, Delta EHEs, etc etc) react.

People have had some success taking fine grain sandpaper and sanding the blades of the rotrons smooth. I have heard that this will reduce noise considerably. People sometimes also have to oil the bearings of the Rotrons which came from surplus stores...

[V12|V12]

Ball bearing fans can quite often develop some extremely annoying and industrial sounding noises when you adjust their power with PWM.

Hrmm, I've tried that before and don't know how or what PWM has to PHYSICALLY do with bearings making noise. Unless the bearing is physically damaged or severaly worn, it will NOT make any noticeable noise based on the type of electrical control of voltage powering the fan. PWN, Or any other type of speed control doesn't have an affect on physical bearings, unless you're touching the rotor... I think it has more to do with sine-wave noise and frequency... the bearings and rotor are totally separated from any current produced by the magnetic field/coils...

People have had some success taking fine grain sandpaper and sanding the blades of the rotrons smooth. I have heard that this will reduce noise considerably...

Again... I've had every fan I've gotten form a surplus store tested before I bought it and NONE of them make these mysterious noises. That and when I'm hand picking a fan, I spin and listen, shake and move the fan to vaguely test for wear/damage etc... Unless you get a full speed 172mm+ fan (4500rpm+) THen if you're running them (12v fans, anything more just won't like lower voltages than 12) at full 12v, and even then they don't make THAT much noise as compared to a full 12v 120mm... in my exp. Again, I just think people are making poor choices when they choose them? I've got LOTS of experience with big fans, I basically spend hours and hours trying them out, to get the best one and even the one's I don't choose are in great running order. :shrug:

People sometimes also have to oil the bearings of the Rotrons which came from surplus stores

I would NOT recommend that at all! Unless you totally overhaul the bearing (IE soaking them in solvent to remove all grease and buildup), b/c of all the fans I've overhauled, every one is grease packed, usually some sort of molybdenum disulfide grease, b/c it's great for high temps, rust inhibitor, resists dust build-up and lasts MUCH longer than oil. Mixing oils with grease packed bearings can result in serious degradation of the grease and result in strange compounds which could actually attack the bearing, depending on the type of oil added and grease inside etc... blah blah.

Either way... if you've got the space for a nice MONSTEROUS fan, I'd recommend trying it out, you won't be sorry. Though, most of those types of fans are around 18-20W+! So if you can find a really high wattage Rheostat (very pricey!) or a fanbus that can handle 18W+ then I'd get one... PWM would need some tweaking based on, I guess others no so good noise experiences? Right now I'm planning on getting more Rotron 120x38mm Whisper XL's since they are ultra quiet, reliable and draw tons of air with minimal noise and high static pressure capabilities... Good luck all!

[jafb2000]

PWM noise is a function of 3 components:
o Bearing thrust & slippage noise from PWM on/off pulses
o Motor IC noise from PWM "average" voltage re rise/fall
o Harmonics as a result of the PWM frequency

1) Bearing thrust & slippage noise from PWM on/off pulses:
o PWM frequency applies voltage as "1 0 1 0 1 0" re on/off
o So there is a resulting mechanical kick to the bearings
o This will result in some noise from acceleration
o Similarly, some noise from deceleration
o The net result is a mechanical addition to rotation noise

PWM relies on mechanical slippage to work - that the rotor-fan
& magnets keep on turning during the "off" period. Thus the
fan rather than using a continuous analog signal is using a
digital signal whose *average* voltage (like r.m.s to a.c.) is
less that the peak voltage of "1" (12V, 24V, 36V, 48V etc).

2) Motor IC noise from PWM "average" voltage rise/fall
o Motor ICs for all DC fans are self-starting
o Many self-starting circuits trigger at a certain voltage
---- and involve a cut-out + delay + re-start process
o This inevitably results in noise varying by fan & PWM specs
---- varying by fan re form of self-start circuit
---- varying by PWM frequency
---- varying by PWM voltage (not all are Vs re fan rating)
---- varying by PWM duty-cycle re 50-70%
o Motor ICs are also designed for V-continuous not chopped
---- the chopper frequency can affect motor-ic quiet-operation
---- quiet hard drives phase head movement into start/move/stop
---- a similar technique is applied to "new low noise motor ic's"

This is usually one of the loudest noise inducers:
o Because self-start circuit involvement results in mechanical noise
o Which has it's own amplitude, frequency & natural frequency

Vis., some fans perform terribly under PWM.

Taking Papst System 3000 PWM 12V controller & Papst 6212NM:
o This sucks re noise quality at lower PWM settings
o The fan will *growl* at a volume *louder* than it's full-Vs use
o The "PWM growl" negates the benefit of the PWM at <80% duty

Most systems aim to run fans at 70% duty cycle, since that is a
good realisation of cfm & static pressure, whilst at the same time
having a disproportionate benefit in terms of bearing longevity.

Taking Papst System 3000 PWM 24V controller & Papst 6224NM:
o Blissful smooth operation from 50-100% duty cycle
o No PWM noise, but no "halving of dB(A)" at 50% duty cycle
o Reason being that the fans have very large ball-bearings

This feature of very large fans isn't unusual:
o Noise is a component of rpm - and also bearings
o Big fans like Comair Rotron Caravel don't half dB(A) at 50%
---- taking a 115/230vac model 450cfm & 45dB(A)
---- at 50% duty cycle you will not see 22.5dB(A) but 30-35dB(A)

Can't recall the figure off hand as I don't use it, since PWM gets
a different dB(A) for reasons 1-2-3 on that fan. However, on the
very big fans there is a base-level noise due to bearing rumble.

It's small - and not unpleasant - just something that shows up in
the dB(A) figure in absolute levels, and subject to preference.

3) Harmonics as a result of the PWM frequency:
o This can be a biggee
o PWM frequency of 1-2kHz on most fans means run
---- they motor and *amplification thro fan mechanics* will growl
---- specifically they will emit a 1-2kHz noise during PWM
o PWM frequency of 10-20kHz is more preferable
---- and tends to increase the number of fans PWM "works" with
o Some work is being done into ultrasound
---- however noise damage in watts in ultrasound is *tiny*
---- so whilst we can't hear it, it can damage us - so vital research

As a function of this PWM frequency, you have bearing interaction.

Overall, there is a critical path of PWM frequency, motor ic type
& self-start circuitry, bearing type & size, bearing/magnet
mechanical characteristics re slippage, and mechanical slippage
of the overall system. Each varies according to each fan. Some
fans seemingly identical bar voltage *sound* very differently.

This is why PWM implementation in industry ends up specifying
a fan which has been proven - another can be unpredictable,
and why PWM is disliked in that production lacks substitution.

Personally I prefer:
o Proven fan/controller combination = PWM if cost permits
o Variable fan in use/replacement = use 2-voltage operation
---- this requires a consideration of hysterisis re control

Hence for the latter I use 24M1A at 12/24V operation, since for
a 128 fan application the PWM array to control it is >400$US. In
comparison a 12/24V controller using industrial DIN 12V PSU in
either series of parallel (designed to permit it) is cheap, 6$US.

My comments were & are re PWM.
However, the bigger fans do have bigger bearings - whilst the
rpm may be far lower (just 1350rpm or less for 254mm fans), so
more of the base-level-noise can be from the bearing themselves.

This becomes especially true into the bigger (300mm+) EBM fans.

The noise, however, may not be intrusive or annoying.
Some people even like the sound of very big industrial A/C, it is
quite loud - but sufficiently white-noise to be easily masked. A
lot of smaller-scale fan "white-noise" has low-period harmonics
in it and these are more easily selected by human perception.

Within about 7-10yrs fans will integrate PWM as standard, not
as present forms, but completely serial-port programmable; may
only be possible for distributors, but is an industry end-goal. In
terms of temperature profiles, low-temp operation & so on.

Biggest gripe over PWM is quiet enough at low temp operation,
yet enough airflow at high temp operation without jumping there
too fast. This is obviously load dependent - and why a quiet PSU
with PWM control may be quiet on one PC yet noisy on another.
In such cases, the noisy PC often has higher thermal output and
often is using the PSU fan as per the ATX spec & profit-remit to
cool not just the PSU but the entire PC - hence high cfm & noise.
If 38cfm is needed at 35dB(A) for a PSU-PC-cooled solution then
offloading it to 2 fans allows 36cfm at a combined silent 17dB(A).


Nothing wrong with larger fans, but ideally one should redesign
a PC case to house them (or multiple PCs in a box similarly). Very
easy to pick up flight cases on castors, portable, rugged, dense.
Then make the PC structure out of nylon & ABS, or aluminium. A
perforated T3R5 alloy (3mm hole, 5mm pitch) is pegboard PC.
Such solutions avoid obsolescence (AT ATX BTX etc), and can be
very economic if used to house multiple PCs in self-made racks.
Vertical racks allow narrow form-factor, passive 1U heatsinks &
use high airflow from larger fans running as required. Keep the
air resistance low (blow bottom to top, blow-thro-cases) and it
can be very quiet whilst very easily and cheaply made.

BTX cases are a very short-term solution, Intel trying to play
catch-up to the Apple Dual G5 - and quite a clumsy nasty design.
That is case manufacturer/integrator/OEM profits speaking tho.

[V12|V12]

WOW! I MUST applaud that response! Very nice, Now I know, and knowing is HALF the battle! G.I. Jo...er okay nm... Okay I see what you mean about the bearing thrusting. Still seems as if a fan with a not so good bearings (Less tolerance between race/ball Bearings) would suffer from this.... but any how, I went and tested a 172mm Rotron I had laying around and at 5v it spins quiet well, good flow, no noise, but you can hear a little whine, but it's not noticeable when inclosed in the computer with every thing one etc...

[jafb2000]

That's great - sounds like a 12V version.

Always check the codes on the Comair Rotron fans, there is
quite a range from ~200-300cfm - and noise varies even more.

The main comments are re PWM, and simplifies to:
o If using a PWM solution try a fan with it before you buy more
o Realise you may have to try several fans re "PWM growl"
o Realise just because one doesn't work, doesn't mean all will not
o Use a high PWM frequency for easier fan+PWM compatability

That's it :-)

[G33k]

My elctronics knowledge is shakey to say the last, but couldn't you use a capacitor to smooth the output from the PWM. That way you'd get less 'kick' in the bearings.. ?

[msv]

jafb2000, of course 45dB at full speed won´t drop to 22.5 dB att half speed. The decibel-scale is logaritmic, not linear. 22.5 dB is slightly less than a quarter of 45dB in noise level.
35 dB is quite much half the noise of 45 dB.
regards
Mikael S.

[jafb2000]

Yes sound pressure level is logarithmic, not linear.
Fan rpm is linear with voltage, the main determinant in fan noise.

For small fans a small drop in voltage gives a large drop in dB(A).
o Ex 3450rpm-2150rpm, gives 69-43cfm and 43-27dB(A)

For large fans, the bearing system is a major noise component
o Ex 1650rpm-975rpm, gives 450-228cfm and 50-38dB(A)
o For another makers same fan the 50% duty is given as 42dB(A)
---- they sound like crap too, just a technical data point :-)

Bearing noise is not necessarily linear with fan rpm/voltage,
the large fan I cite has sealed IP54 bearings & high-temp ok.

Bearing noise need not be objectionable.
Walk into a big supermarket, or even big old mainframe room
and you'll hear a lot of bearing noise that isn't too obnoxious.
At least in contrast to a PC 60mm Delta fan doing >6800rpm.

For PWM control of fans, the dB(A) figures can go out the window.
The quieter 38dB(A) large fan I cite at 50% voltage, is a dog
with PWM and growls louder than at 100% voltage operation.
The noisier 42dB(A) large fan works fine with PWM - reason is
the kinetic energy of the bearing/rotor/magnet-structure has
far more slippage and negates the PWM mechanical interaction.

Sometime someone should print a PWM-ideal-per-exact-fan test.
Instead many bi-voltage fans, eg, 24/12V switched for hi/lo as
Compaq & many more do (IBM) - far cheaper than PWM solutions.