Sonata PSU air channel/separation from CPU

akerr63 · Post by **akerr63** » Wed Jan 19, 2005 9:42 pm

Inspired by the many great Sonata mods on here, I'm currently prototyping a (cardboard) air duct/baffle/channel for the PSU intake. The idea is to direct air from the standard front panel intake to the PSU, and avoid the PSU sucking in hot air from the CPU (which is almost directly underneath the PSU intake). This is similar to the BTX case design - separate the PSU air from the CPU air. The benefit of this design is that it does not impact the 5.25 or 3.5 inch bays, nor the HDD bays. And it retains the visual appearance of the Sonata (the front door is still usable and can be closed).

The prototype channel has a full width plate underneath the PSU, sealing off the upper portion of the case with the PSU from the motherboard/cpu. This plate stops about 2" before the 5.25 bays, and joins up with a vertical plate that is about 1-2" to the left of the HDD bays. This vertical plate ends about half way down the HDD bays. Air is supposed to get pulled up this channel, across the HDDs and into the PSU. However I think the current prototype has too little space at the corner, next to the 5.25" bays.

Results below are with the inner bezel mod (removing the useless slats) already done, and with the "ANTEC" holes and all other air intake points, except for the filtered intake, temporarily taped up. (Note: on newer Sonatas the inner bezel slats have already been removed in the molding from Antec!)

Results so far are interesting but not great. The motherboard/CPU temperatures are identical, and the PSU fan spins about 100 rpm slower than with no channel (implies the PSU is cooler). However this is still about 100 rpm faster than with the side door completely removed providing a larger volume of cool air. Also there appears to be airflow restriction in the channel, since on immediately removing the side door the PSU fan speeds up by 50 rpm (although this is true even without channel).

Also it is not quite quiet enough yet - still need to swap out the rear fan and use a lower speed cpu fan (have both on hand). But I wanted to try this channel idea first.

My end goal is to have quiet _and_ sealed the Sonata execpt for one filtered air intake, due to being in a dusty environment (cats!). I'm also considering cutting a huge hole in the base, using a pleated air filter, putting the Sonata on longer legs, and sealing the front air intake. The PSU channel would then extend to the case bottom. However I wanted to start with less drastic mods first!

Do any of you creative talents on here have other suggestions other than PSU replacement or PSU fan replacement?

burcakb · Post by **burcakb** » Wed Jan 19, 2005 11:31 pm

Well, I once tried a duct with Sonata. I mainly tried to seperate the CPU area and the PSU, have the PSU suck in cool air from the Antec holes. I'm guessing the total area offered by the Antec holes is larger than the duct you created. Even that wasn't enough, the PSU literally SCREAMED for more air. Despite the hot air coming below from a hot CPU, the PSU seems to need the volume.

So I'm sorry, short of changing out the PSU, there's really no nice way. I've already done a fan-swap (I have an Acoustifan in there now), the antec holes are still open, there's no seperation between CPU & PSU, I use a MUCH cooler CPU but still the PSU is my noisiest component

j-azn · Post by **j-azn** » Thu Jan 20, 2005 6:34 am

I dont know if i'm talkin about the same thing here, but my Sonata came with a ONE fan PSU and i say its pretty hard to suck in hot air from the CPU because there are those holes on the side that spells ANTEC to give it cool air. Its not alot, but i think it is sufficient to overtake the hot air from CPU

akerr63 · Post by **akerr63** » Thu Jan 20, 2005 12:29 pm

Good comments. I just did some quick calculations on areas (should probably have done this first!). If you assume air in only comes from the four front slots/cicles underneath the plastic filter, then that area is about 7,000 mm2. The PSU inlet area, allowing for 15% metalwork reduction, is about 5,400 mm2. The rear case fan outlet size, allowing for 10% metalwork reduction, is about 10,200 mm2.

So the inlet area is less than half the outlet area, with negative pressure as well! No wonder the Sonata is starved for air.

However if you cut a large hole in the Sonata base next to the motherboard, and allowed for 2cm all round, that hole would be 31,000 mm2, or twice the size of the outlets. However that does not solve the cool air inlet duct to the PSU. It seems either a 5.25" bay duct is required, or a side/top inlet duct. Of course all these holes then need filtered, and noise reduction applied to reduce noise path to the outside.

Any comments? I'll think about these ideas for a day or two before cutting into my Sonata!

stighenning · Post by **stighenning** » Thu Jan 20, 2005 12:42 pm

I can't wait to this gets out.. weeeee

akerr63 · Post by **akerr63** » Fri Jan 21, 2005 7:19 am

One comment on separating the PSU from the CPU area with a duct or other divider. I noticed that the "tonal" quality of the system noise changed and was less annoying, particularly from the rear case fan. I'm guessing that with the PSU not sucking air from around the CPU/rear case fan that air flow is more linear / less chaotic.

peterson · Post by **peterson** » Fri Jan 21, 2005 7:47 am

akerr63: I did just this. And from my experience it works just fine.

I made a duct from a sheet of aluminium and put it on the 'beams' in front of the PSU. Well, it's more just a plate working as a duct.

My theory was to get fresh air from the 'ANTEC' holes in the chassi rather than warm air from the CPU. I can hopefully show you a picture tomorrow.
Oh, and btw, i also made a fan swap + installed a second fan pushing air into the PSU. Piece of cake if your the least handy

And having larger output area than input. Colder air is denser and therefore it requires smaller area.

/Lars Peterson

burcakb · Post by **burcakb** » Fri Jan 21, 2005 1:27 pm

akerr63,

peterson's mod has a second fan on the PSU. While a second fan might increase the noise, since you've covered the antec holes and have a duct "down", the second fan might turn out to be inaudible AND the setup could work. Worth a try definitely

JanW · Post by **JanW** » Fri Jan 21, 2005 2:07 pm

Just a quick question, akerr63: did you seal your downward duct towards the front, and if so, how do you feel about the (now absent) cooling of the optical drives?

Some background: Just yesterday I did a similar mod on my Sonata to resolve PSU intake issues (for a 120mm fan PSU), that involved sealing the case towards the front (I'll put up a post, once it has stabilized). And that has left my DVD burner lined with foam on the bottom, and "cooled" only by some really slow moving hot air exhaust from the PSU on the top

Don't quote me saying "it's been done" 'cause I haven't yet dared to burn a CD/DVD with the new setup...

akerr63 · Post by **akerr63** » Fri Jan 21, 2005 3:20 pm

JanW wrote:Did you seal your downward duct towards the front, and if so, how do you feel about the (now absent) cooling of the optical drives?

Jan - You raise an excellent point that I was wondering about too. My duct is formed using the front HDD, 3.5" and 5.25" bays, with a vertical panel between the rear of these bays and the motherboard. Also my burner has an empty bay below, and an almost empty bay above. However there will not be a lot of actual airflow over those surfaces. I suspect any air is likely flowing round the rear/sides and not over the top/bottom surfaces. I now have a DigitalDoc 5+ and plan on experimenting this weekend. I'll post results here.

StarfishChris · Post by **StarfishChris** » Fri Jan 21, 2005 3:58 pm

If you have a rear exhaust and a PSU intake fan at the top with panel holes uncovered, would this help get cool air through the holes?

I have the later PSU version with front-facing air holes and may contemplate attaching a 60mm or 80mm fan to them.

JanW · Post by **JanW** » Fri Jan 21, 2005 9:36 pm

akerr63 wrote:My duct is formed using the front HDD, 3.5" and 5.25" bays, with a vertical panel between the rear of these bays and the motherboard.

Forgive my stupidity, but just to be painfully clear: You have two vertical panels for your downward duct, one immediately behind the bays and running all the way to the top, sealing it towards the front, and one 1-2" further into the case sealing it towards the M/B area?
In that case we are in a very similar situation. I'm extremely curious to hear about your temperatures.

akerr63 · Post by **akerr63** » Fri Jan 21, 2005 10:22 pm

Starfish - I also have the later PSU with only front-facing holes and a rear exhaust fan. But I am covering my "ANTEC" holes to prevent dust intake. If the holes are uncovered, the PSU runs cooler (slower fan). I'm not sure about the extra fan idea. I've come to the conclusion the biggest issue is lack of air into the case. Reading many forum posts the solutions are variations of: keep the holes open, close them up and live with noise, replace the PSU fan or PSU, or duct cool air in.

Jan - I only have one vertical panel 2" further into the case. I was trying to use the entire drive bay stack as part of the channel to (try to) funnel extra air to the HDDs and optical drive. It did help the PSU, but I didn't record any drive temperatures yet.

lenny · Post by **lenny** » Fri Jan 21, 2005 10:44 pm

j-azn wrote:I dont know if i'm talkin about the same thing here, but my Sonata came with a ONE fan PSU and i say its pretty hard to suck in hot air from the CPU because there are those holes on the side that spells ANTEC to give it cool air. Its not alot, but i think it is sufficient to overtake the hot air from CPU

The exhaust from my Sonata's PSU has always been hotter than the exhaust from the 120mm fan below. Significantly hotter. System power draw shouldn't be that high (estimate 150W AC draw max, so assuming 70% efficiency, there'll be 45W of heat dissipated in the PSU).

I was just toying with this very idea. I'm surprised it didn't make more difference.

stighenning · Post by **stighenning** » Sat Jan 22, 2005 1:54 am

lenny;
I experience the same as you do, with the PSU exhausting alot hotter air than the 120mm fan below.

I have read alot of messages...puh..
And it seems that the harddrives are making alot of heat.
And they should have a better airflow - to make them last longer, and also to reduce the heat in top of the box.
I tried mounting a Papst P4412FGL beside the harddrives, and it did cool them down, but the fan makes to much noise. Probebly because it goes at full speed. (1600rpm), so next is to buy a FANMATE2, and connect this - so that I can controll it down to 1000rpm.

I read alot about the Tagan PSUs. They seem to to a great job, having 2 fans, and are very, very quiet. (I just read this, but haven't check it myself)

I was thinking of buying the Nexus NX-3000. Got great reviews and also doesn't make that much noise.

..but then again, if my sonata is to warm, I guess the NX-3000 will also spinn up the speed - making it noise aswell.

So bottom - is the best way to use PSU with 80mm fan in back, and a 120mm in the bottom ?

btw; my friend bought the Silentium T1. And it has a great design inside!
Keeping the PSU at bottom, and 2 fans at the top. Brilliant!
Look at the pictures on this link. (sorry, text in norwegian)
http://forum.hardware.no/index.php?show ... 63977&st=0

peterson · Post by **peterson** » Sat Jan 22, 2005 2:44 am

Well this is my current solution in the PSU duct subject.
I will cut out the PSU case behind the fan later but i just wanted to test if there waas any difference. The two fans (one at the inside/rear of PSU) are Pabst spec. to 12dB. They're very quiet but still audible. So either my ears are great or they're not 12dB.

The "duct" is just a peice of aluminium whit a hole for the cables. The CPU may be one or two degrees warmer but the PSU gets up to three degrees cooler. And that's more important IMO. I use a sensor in the PSU connected to a T-Balancer.

nici · Post by **nici** » Sat Jan 22, 2005 5:27 am

Looks nice

Im actually just doing something similar.. More details when its finished soon

stighenning · Post by **stighenning** » Sat Jan 22, 2005 6:38 am

Great work, Mr Peterson

Your papst is running at high speed. You should have a FANMATE2 or something to regulate the power.
(I'm going to put a FANMATE2 on the 120mm fan in the back of sonata'n.)

peterson · Post by **peterson** » Sat Jan 22, 2005 6:57 am

stighenning wrote:Great work, Mr Peterson
Your papst is running at high speed. You should have a FANMATE2 or something to regulate the power.
(I'm going to put a FANMATE2 on the 120mm fan in the back of sonata'n.)

Max speed for my Pabst is 1500rpm. And in stead of a Fanmate i use a mCubed T-Balancer

So all my fans are changing speed automatically. So at idle, it's very silent.

andyb · Post by **andyb** » Sat Jan 22, 2005 10:58 am

A question for everyone here who has posted to this topic.

Can you state.

1, Whether you have Version 1 or 2 of the PSU.
2, What speed your fan is running idle/load, and ideally your PC spec + mods as well.

Mine is currently, idle 1GHz

Only Mod is front intake vent opened with stanley knife (didnt make a lot of difference.

CPU Temp 45
NB Temp 37
CPU Fan Speed 743
PSU Fan Speed 1360

System Specs are below.

Andy

JanW · Post by **JanW** » Sat Jan 22, 2005 1:49 pm

Here you go:

PSU version: 2 (same as in petersons pictures)
PSU fan speed: 1467 (that's under load (F@H), don't know about idle - it never is )
Antec holes: uncovered
Mods: almost exactly like peterson (AcoustiPack foam coating for the case, PSU area separated from M/B - only I used cardboard covered with dampening foam, not aluminum, and it looks way messier )
System spec: see sig

stighenning · Post by **stighenning** » Sat Jan 22, 2005 3:41 pm

PSU v.2

CPU Temp 47
MB Temp 33
CPU Fan Speed 1360
PSU Fan Speed 1630

StarfishChris · Post by **StarfishChris** » Sat Jan 22, 2005 7:17 pm

PSU v2. No mods (yet)

CPU Temp 28
Motherboard 35
CPU fan speed too slow for detection
PSU fan speed undetectable by motherboard (trying to fix this one)

stighenning · Post by **stighenning** » Sun Jan 23, 2005 1:31 am

peterson;
Wonder if this idea would work with a fanless PSU ?
Or do you think it would get too hot ?

StarfishChris
What are your computer specs ?

peterson · Post by **peterson** » Sun Jan 23, 2005 2:02 am

stighenning wrote:peterson;
Wonder if this idea would work with a fanless PSU ?
Or do you think it would get too hot ?

That's a different story. I think it would be difficult for air to go that way w/o help. But i don't know. I plan to get a Phantom 500 when it get's out so maybe i'll get an answer then

These are my values as reported by T-Balancer.
PSU: 716rpm @ 59°C
CPU: 788rpm @ 46°C (3.0GHz Prescott, XP-120 cooler)
GPU: 1213rpm @ 62°C (6800GT w VF700 cooler) (non calibrated is 50°C, but i compensate to be safe)
MB: 422rpm @ 41°C. (Measured on northbridge heatsink.)

StarfishChris · Post by **StarfishChris** » Sun Jan 23, 2005 4:51 am

Now with handy signature!
I always thought it was the PSU fan causing most of the noise on my PC (except for the optical drives, but they need a disc to take off), so I turned off fans using SpeedFan and went to standby mode. Everything turned off except for PSU fan, the difference was just audible (that of the hard disk).

peterson, was the exhaust air any cooler after what you did?

peterson · Post by **peterson** » Sun Jan 23, 2005 6:30 am

StarfishChris wrote: peterson, was the exhaust air any cooler after what you did?

I really don't know since i reduced speed i suppose it's a bit warmer now than before. But it should be cooler at full speed even though the fans only do 1500rpm and the original fan used to spin at 1700rpm. I hope the extra fan compensates to better airflow than before. But i can't measure it.

akerr63 · Post by **akerr63** » Sun Jan 23, 2005 7:41 pm

Finally built version 2 of the duct and it seems to works very well (although currently all cardboard and tape!).

1/ Blanked off the entire LHS of the HDD bay (on the motherboard side) so no air can get into the motherboard area but the HDD bays are still usable. The HDD bays now form a sealed tower except for the standard air inlet, and the top.

2/ Added a divider 2" away from the rear of the 3.5" and 5.25" bays. This divider joins to the top of the HDD bay and seals off the height of the case from here to 3/ below. So air from the front air inlet can only go through the HDD bay and then through the 3.5"/5.25" bays and the extra space in front of the divider.

3/ Placed a full width plate under the PSU that joins with 2/ above, and sealed the "ANTEC" holes. So the PSU sucks the air from the front air inlet, through the drive bays, and out the rear.

4/ To provide air to the now sealed off motherboard compartment, cut a 7"x5" hole and covered it with (cut-out part of a) pleated HVAC air filter. Currently the hole is in a cardboard side covering (for testing), but it will be in the base with the Sonata raised about 3" to allow air in. The 3/4" filter is mounted in 3/4" aluminum channel which is attached to the Sonata with magnetic adhesive tape.

This, along with a new front filter and sealing the front door edges, should keep out the dust. Temperature wise the unmodified original TP380S runs about 1430rpm, the Seagate 160Gb HDD runs about 30C idle (about 35C under load), and the XP2500+ CPU/SI-97 is about 44C idle (ambient is 24C). I need to reseat the CPU - used to much TIM the first time. With more air in the motherboard area, I was also able to reduce the rear case fan to minimum using a Fanmate2. Also the single HDD, mounted on the drive bay as standard, appears quieter. It is in the internal top bay slot, so either the drive cage is more rigid there, or by mounting higher less noise escapes from the front.

I've got some other ideas, including trying peterson's idea of a fan in front of the PSU, ducting the new inlet air straight to the CPU, and swapping some fans around. Silent (and dust free!) computing is addictive

. Thanks for all your posts!

JanW · Post by **JanW** » Mon Jan 24, 2005 12:53 am

Sounds like excellent work!!

akerr63 wrote:...along with a new front filter...

What did you use for that front filter?

stighenning · Post by **stighenning** » Mon Jan 24, 2005 1:43 am

Pictures, dude!! Give us pictures

(read this thread on how to post, simple: http://forums.silentpcreview.com/viewtopic.php?t=18650 )