Silenx 120mm fans and heater cores...?
 

Has anyone tried using these (quite expensive) fans to pull air through a 2" thick heater core? For that matter, does anyone have both the 14dB and the 11dB models? From the photos, the two look identical, both draw the same power, so I'd guess the difference is a resistor...? Which would mean the 14dB ones were more appropriate - and then I can add my own resistor/rheostat/diode-stack/whatever to adjust down if necessary.
I'm also guessing that I'd need to "stack" a pair of these to get sufficient pressure - but maybe not (?) as these fans are designed for low speed / low flow and may have stall points low enough that they're OK for what I'm doing.

The silentx stuff is mostly wishful thinking.

http://forums.silentpcreview.com/viewtopic.php?t=16393

spcr is slowly testing fans.. the nexus 120mm...
12V : 38~41 cfm : 22~23 dBA/1m
9V : 31~33 cfm : 19~20 dBA/1m
7V : 23~24cfm : <18 dBA/1m
5V : 15 cfm : <17 dBA/1m

nexus $20 the globe is $8... i woudln't bother trying anything else, at least other dc fans.

Hi bobkoure,

I have a 120mm silenX 11dBA fan, it does use a resistor to slow it down, which can be removed, I have also ordered a 2" thick heater core, so we're on the same boat with this one.

All I can comment on is that, they are ******* quiet, I mean, you just can't hear these things! And they do move a descent amount of air, as long as you use a shroud I don't see any problem.

Maybe someone out there has theirs' up and running with a 2" h/core?

Anyone?

(BTW Becks, that might be counterfeit silenX stuff you're looking at, that's not a genuine silenX PSU on that site.)

SilentX doesn't make anything, how could there be counterfit stuff? :P Adda makes their fans, if you want more realistic specs look at adda's fans... the silentx fans are quiet but their specs are made up... for $24 you're still better off buying a $19 nexus.. which is pretty much agreed upon to be the best.

"Highly Efficient Hypro Bearings" = an adda fan

You'll get better flow/noise ratios for 120x120x38mm fans when you hook then up to a radiator because thicker fans tend to have less steep flow verses backpressure graphs IIRC.

Right - but 120x120x38 (or thicker) quiet fans seem to be pretty thin on the ground. Panaflo L1As and...?

There are no 120x38mm DC fans that are really quiet. For quiet 120mm fans you either need to get a Nexus (by far the best choice), or a Globe S1202512L-3m and undervolt that. Both of those are only 25mm thick.
The other option is to use an AC fan. I use Sunon 2123XST 230V fans and run them on 120v. A 2 Watt series resistor somewhere in the 270 ohm to 750 ohm range can be used to lower the rpm further to suit your noise tolerance. These are 120x38mm fans and are very quiet when undervolted like this. They have a better airflow vs noise ratio than even the Nexus fans and do better against backpressure. They do have some vibration to them so it's best to mount them with vibration isolators. They are heavy metal frame fans, but only cost about $9 from http://www.alliedelec.com/Catalog/pf.asp?FN=551.pdf

In saying that though, I really can't compare Adda to silenX fans. My Lian Li had Adda fans. With silenX the blades are completely different, almost razor sharp and shaped different, they might be O.T.T specs on them, but they are very quiet. Just too damn expensive.

I've ordered a pair of those nexus 120mm fans. Will report back on how they do pulling air through a 6x6x2 heater core. Will probably only try on the pull side, both single and stacked (with spacer) and only have MBM to indicate "how I'm doing" flow-wise and ears for noise-wise.
Bob

Hmm, I just spun up my 120mm silenX,

14dBA at 1 meter? They wouldn't be that at 10 meters. Their 80mm fans are excellent, but their 120mm ones are no better than anything else on the market. Talk about marketing bullocks.

I think I'll jump off the silenX bandwagon now. But their PSU's and 80mm fans are excellent.

How have these worked for you in the long term?
Any overheating or other issues at 120v?

My pair of 120mm Nexus (Bright Orange) fans are set for delivery Monday ;) One is destined for the rear exhaust of my shuttle lan pc, the other for my "silent" pc rear exhaust.

Hope they live up to their reviews.

I just bought 3 SilenX 120mm fans and an 80mm, and I have to say they are the quietest fans I've heard. I have panaflo lows, and panaflo highs that are undervolted, and well as some Vantec stealths, and the SilenX are definitely the quietest, and they still move a nice amount of air..

You guys should keep in mind that Ahanix is selling rip-off SilenX stuff. I got mine from a registered Distributor (Bigfoot Computers) so I know they're authentic. I wouldn't buy them from anywhere that's not a registered distributor...

Yeah.... the thing is, the only fans in there that I wouldn't classify as "Loud" are the Panaflo L series ones, and even then only the 80mm ones are really quiet, with some QC problems in the newer ones and having to be undervolted to 7v or so to be properly quiet.

Nexus with 6x6x2 rad
 

I got a pair of Nexus 120mm fans in to try with my 6x6x2 heater core.
I had previously been using a pair of 120mm Panaflo L1As (grey label) at 5V, stacked on the pull side with a 25mm plenum (hollowed out fan body) between.
This previous setup worked about the same (MBM based - diode minus case) as a single L1A at 7V but was quieter.
While I was at all this, I tried various configurations of push/pull, push-stacked, and pull stacked and tended to get best results with pull stacked (typically push/pull offered no benefit over single pull)

So.. I have tried the Nexus fans
- single pull - same temps as 7V L1A / stacked pull L1As at 5V
- stacked pull - 1 or 2 C cooler than 7V L1A / (as above).

Single or stacked, they are quieter than a single L1A at 5V (which was useless with a 2" radiator, BTW).
Stacked, slightly louder than single (no idea if it's actually the theoretical 3dB or not - too quiet for my ears to tell - will try all this again the next time I'm up at 2AM and it's quiet around here...
I may also try speed-controlling the Nexus' down to the same apparent noise level as a single one and see how that compares temp-performance wise.

CAVEAT : I am measuring / comparing sound with my ears all be it late at night when background noise is low - and I am measuring airflow performance by looking at the delta between case temp and diode temp as reported by MBM which isn't any kind of accurate or even linear (although case temps seem to go up and down exactly in lockstep with the temp readings of the wall thermostat.)

note - I also posted this in this thread at SPR.

I got my 2 Nexus fans.. In open air with no electronics on.. ~11pm in my quiet neighborhood.. no room fans AC etc on... I couldn't hear the fan motor or air displacement in free air at arm's length.. I could only hear the soft air movement noise at ~ 5 inches likely a result of the air passing over my hear!

Of course I could be deaf but I don't think so..

No, they don't even get warm. They are exceptionally quiet, even better airflow to noise ratio than the Nexus.
The fans are available from Allied electronics for $9 stock number 997-2123
http://www.alliedelec.com/Catalog/pf.asp?FN=551.pdf
You can speed control them very nicely with a 1K 3 watt pot also from Allied for $5
stock number 522-0049
Allied has fan cords for them for about $1 Stock number 609-5642 for a 3' cord with a straight connector.
Dimmer modules and fan speed controllers don't work very well with them. Use the pot. You will need one pot for each fan, don't stick two fans on one pot. You can either just leave the fans plugged in all the time or use a pump relay to turn them on and off.

I have an embarassingly large collection of 120mm fans. The Silenx 120's are pretty decent, but very overpriced. They perform almost identically with the Globe S1202512L for noise vs airflow except they have a bit of motor tick noise that the globes don't have. There is no point in getting the Silenx 120's when you can get the globes for considerably cheaper and the globes run a bit faster at 12V also. The Nexus 120 beats them both easily for airflow vs noise and so is the best choice as long as it flows enough air for your application at 12V. If you need more airflow than that it's not going to be really quiet no matter what you do. You could go with a globe. The problem with the 120x38mm DC fans from Panaflo, Papst, and Sunon is they have a lot of motor noise that you just can't get rid of at any speed. The only decent option for 120x38 fans is the Sunon 2123XST 230V ac fan running at 120V

SilenX are famous for quoting mysterious figures of dubious origin on their products. Nexus or globalwin are the best quiet fans to go for so get a pair of those if you want. almost bought some myself til research lead me to various rants :D

ferdb,
How do you think those 240v sunon fans compare (at 120, potted) to these 120x25 deltas (that I'm using for my heater core now, but at 7v)?
http://www.cooltechnica.com/Merchant...ategory_Code=F

The Sunon 2123xst are a 120x38mm fan so they handle backpressure better than 25mm fans. They are superior to every 120x25mm fan I have by a large margin, and I have a lot of fans (Adda, Compuman, Zalman, Nexxus, Globe motors, Globe Fan, T&T, NTB, Papst, Panaflo old and new, Sunon DC, Silenx, Bi-Sonic and some others I can't remember). They have almost no bearing noise. As far as I know they are the best 120mm fan for airflow/noise that's available. Just dial them up to your rpm/noise preference.

At 120V (125Vac in my case here) they run at about 1200rpm down to about 650rpm at the minimum pot setting. I find 1200rpm is more than sufficient for me as an upper limit. If you need higher rpm than the Sunon's run stock at 120V then put a 2.2uf capacitor in series with the fan and it will boost the top speed considerably to a brisk 2500rpm. At this point it is no longer even remotely quiet but it is moving a serious amount of air (about 85CFM free air). a 4.7uF cap will boost the top speed to around 2100rpm, adds less heat to the pot than the 2.2uf, and fan rpm is less sensitive to line voltage fluctuations. Unless you need the speed though I would not put any cap in as it increases the heat dissipated in the pot. Don't forget to use a non-polar cap that's rated for the voltage. These fans never get more than slightly warm running at any speed from 2500 down to 0.

The fans are here http://www.alliedelec.com/Catalog/pf.asp?FN=551.pdf stock number 997-2123 at $9 ea
Pots are here http://www.alliedelec.com/catalog/pf.asp?FN=1233.pdf Stock number 522-0049 at $5 ea
2.2uf caps are here http://www.alliedelec.com/catalog/pf.asp?FN=1127.pdf stock number 612-0553 about $1
4.7uf caps are on the same page stock number 613-0500 about $2
Fan cords are here http://www.alliedelec.com/catalog/pf.asp?FN=549.pdf Stock number 609-5642 for 3' cord straight connector for $1.2

Allied has a minimum $25 order, but 2 fans plus parts covers that.

Note that the pots are rather large but they will fit into a 5 1/4" drive bay panel.

I have designed a fairly cheap and simple circuit that allows me to control my AC fans with the programmable T-Balancer fan speed controller (or any speed controller for that matter). It works well but it's a linear solution with about 4 watts dissipated in it worst case so I'm working on a switched mode design to see if I can avoid the heat without generating an unacceptable amount of noise in the fan. It's neither as elegant nor as noise free as I'd like yet.

Currently I use a Criticool pump relay to turn the fans on and off with the computer
http://www.criticool.com/Powerplant.html
This one is convienient since I just glued some perf board to the card and added my extra control circuitry for the T-Balancer. You could also just leave the fans on all the time.

I would love it if somebody else besides me would try out these 2123xst fans and leave some feedback on their experiences.

I just ordered a pair of those sunons to go on a BIP 2 I also ordered. I'll update this post with my observations.

Those are nice fans. On the black ice pro 2, they are very quiet and move a decent amount of air...more air and much quieter than the delta 1212M's I had at 7v on my old heater core.
I'm running them on straight AC here (no pots or caps)...110v I suppose.

In my rig dT water/air is between 4-6C, depending on load (6c under cpuburn, 2415 MHz 1.95 Vcore, plus the OCed 9800p).