Search found 124 matches

by ferdb
Tue Jan 01, 2008 12:57 pm
Forum: Fans and Control
Topic: Need fans but must be 120v ac
Replies: 9
Views: 3194

I can highly recommend the Sunon DP200A-2123XST. These are 230VAC fans, but will run on 120VAC at about 1300 rpm. They are exceptionally quiet for the airflow on 120VAC. You can buy them from allied electronics. http://www.alliedelec.com/Catalog/pf.asp?FN=551.pdf These fans are 120x38mm. These have ...
by ferdb
Sat Jun 18, 2005 11:00 am
Forum: Fans and Control
Topic: Did Diodes Die?
Replies: 35
Views: 11211

It's a common misconception that diodes always drop 0.7v each. It's a very rough rule of thumb and it depends on the diode and the amount of current you are pulling through it. The voltage drop of a diode depends on the type of diode and the current density through it. It is a logarithmic relationsh...
by ferdb
Tue Apr 26, 2005 5:10 pm
Forum: Fans and Control
Topic: The Top SPCR Quiet 120mm Axial Fans Compared + 120mmAC Fans.
Replies: 197
Views: 404985

Yes I should have made it clearer that the 5W pots are only suitable for the 230v fan models running on 120v that I mentioned in the threads or fans with similar current drain. Other than that you should definitely calculate out possible power dissipations. If you run into power dissipation limits w...
by ferdb
Tue Apr 26, 2005 7:09 am
Forum: Fans and Control
Topic: The Top SPCR Quiet 120mm Axial Fans Compared + 120mmAC Fans.
Replies: 197
Views: 404985

DrCR - I just don't around to any forums much these days. Doing other things. Everytime I don't 'hear' my computer running anymore I'm glad I found spcr forums to answer all my noise woes. As for speed controlling the AC fans, I found the 5 watt pots I mentioned in that AC fan thread to be the simpl...
by ferdb
Tue Apr 19, 2005 12:24 pm
Forum: Fans and Control
Topic: The Top SPCR Quiet 120mm Axial Fans Compared + 120mmAC Fans.
Replies: 197
Views: 404985

This is a late response to the question on 38mm vs 25mm thick fans. I don't frequent this board much anymore. 1) the thicker fans handle backpressure considerably better than the 25mm fans, the airflow isn't reduced as much when mounted on a radiator. However the 25mm fans have such a better startin...
by ferdb
Mon Feb 28, 2005 11:22 am
Forum: Fans and Control
Topic: Need a pair of 120mm fans that can push 80-100CFM
Replies: 15
Views: 4569

I would try the Nexus fans first, they will probably work better than you expect. Also don't pull hot case air through your radiator. Get cold air from outside the case through it or your system temperatures can be 10-20 degrees hotter.
by ferdb
Thu Feb 24, 2005 6:45 pm
Forum: Fans and Control
Topic: Need a pair of 120mm fans that can push 80-100CFM
Replies: 15
Views: 4569

If you haven't got the radiator yet, get the BIPro. You will get better results with it than the BIX because it's not so restrictive. The BIX has an advantage only when you put a howling fan on it, at lower fan speeds the BIPro will outperform it. BIPro is cheaper too. You can put a BIPro 2 in a Che...
by ferdb
Wed Feb 23, 2005 12:24 pm
Forum: Fans and Control
Topic: Need a pair of 120mm fans that can push 80-100CFM
Replies: 15
Views: 4569

It's unfortunate that you have a BIX radiator. The BIPro models work better when noise is a concern. The BIX models are too restrictive and you will have to run your fan faster to get the same airflow as the BIP. Also a double size radiator would have helped immensely in lowering noise. Ah well, nex...
by ferdb
Wed Feb 16, 2005 6:14 am
Forum: Fans and Control
Topic: Effect on blocking airflow?
Replies: 3
Views: 1185

If your PSU has a thermally controlled fan (speeds up when the PSU gets hotter) then there will probably be little effect other than your fan MAY run a little faster. The original reason that 120mm bottom fans were put in PSU was to help cool the processors back when they were starting to get out of...
by ferdb
Wed Feb 16, 2005 5:59 am
Forum: Fans and Control
Topic: simple question.....
Replies: 4
Views: 1523

A guess would be that your fan controller is using the 3rd wire that's normally used for the RPM sensor for supplying full voltage to the LEDs, while it reduces the voltage to the fan motor itself. You could check this hypothesis by connecting only the fan motor connections and not the 3rd wire. The...
by ferdb
Mon Feb 14, 2005 6:09 pm
Forum: Fans and Control
Topic: 14cm fans versus 12cm fans - diminishing returns?
Replies: 3
Views: 3607

Theoretically you are correct. However when you try to apply that in the real world you run into problems. Such as that fans larger than 120mm almost invariably have ball bearings which constitute a large noise source if you are running things slow. The larger fans also are usually designed to flow ...
by ferdb
Mon Feb 07, 2005 2:30 pm
Forum: Fans and Control
Topic: Stupid physics question: Will impedance effect RPM?
Replies: 4
Views: 1454

Typically fans draw less current and spin faster with lower flow (increased airflow impedance). I would suspect an electrical or fan difference in your case, not an airflow difference.
by ferdb
Thu Feb 03, 2005 3:08 pm
Forum: Fans and Control
Topic: Magnetic Floating Bearing (MFB)
Replies: 6
Views: 3199

I've played around with a Sunon Maglev fan before. It was not any quieter than other fans, about average really. Still had significant bearing noise.
by ferdb
Wed Feb 02, 2005 2:41 pm
Forum: Fans and Control
Topic: Alternate Adda/Ahanix/SilenX supplier?
Replies: 12
Views: 2760

The SilenX fans are not better than the Nexus fans, although they aren't that far off. The Silenx published noise figures are complete marketing bullshit and have no basis in any reality. The fans are comparable to the Globe fans, but at several times the price. I've developed a dislike for Silenx b...
by ferdb
Mon Jan 31, 2005 10:43 am
Forum: Power Supplies
Topic: What's recommended available 400+W supply for Nforce4 PCIe
Replies: 3
Views: 1343

What's recommended available 400+W supply for Nforce4 PCIe

Need to build two quiet systems, both Nforce4 based (not SLI) PCIe. They will have med-high end power sucking graphics cards in them, Fast clocked 90nm AMD64s, and 4 SATA drives in each. I'm intending to build these in Antec SLK3000B cases, with XP-120 HSF. If anybody has comments or suggestions abo...
by ferdb
Fri Jan 28, 2005 2:59 am
Forum: Fans and Control
Topic: Will resistors really do the job?
Replies: 29
Views: 9838

To measure this drop I used a small brick transformer, the diode cable & a 12cm Panaflo fan. I have since repeated this test & got broadly the same result. I have also taken measurements from a spare 3pin plug on my PC & got quite a different result :? Anyway, here are the figs. If you could make s...
by ferdb
Thu Jan 27, 2005 3:01 am
Forum: Fans and Control
Topic: Will resistors really do the job?
Replies: 29
Views: 9838

I was surprised to find 3 Rectifier Diodes in series. They are marked 1N5401 gave a voltage drop of 4.6v. Using a string of diodes is an old tried and true method of dropping voltage. I'm a bit puzzled by your results though. The 1N5400 series are 3 amp rectifiers and usually have a drop of around ...
by ferdb
Wed Jan 26, 2005 3:47 am
Forum: Fans and Control
Topic: Easiest way to slow down a 240v AC fan?
Replies: 8
Views: 5349

you can stick the bulb in a lamp obviously. connect one wire (or prong of the plug) of the lamp to one wire of the fan. Connect the other wire of the lamp to one wire of the AC socket, connect the remaining wire of the fan to the other wire of the ac socket. You should end up with a loop from one AC...
by ferdb
Wed Jan 26, 2005 2:58 am
Forum: Fans and Control
Topic: Easiest way to slow down a 240v AC fan?
Replies: 8
Views: 5349

usually multi-speed fan motors have different winding arrangements to allow the different speeds. Not something you can modify really.
A quick and dirty way to slow it down though may be to put the fan in series with a light bulb, try different wattages to see what you get.
by ferdb
Tue Jan 25, 2005 3:32 pm
Forum: Fans and Control
Topic: Easiest way to slow down a 240v AC fan?
Replies: 8
Views: 5349

It just occured to me you are probably on a 230V system and would need a 230V compatible Variable transformer (Variac) for your application. I would direct you toward Ebay, where I have seen a large variety of such items that would satisfy your requirements. Good luck
by ferdb
Tue Jan 25, 2005 3:29 pm
Forum: Fans and Control
Topic: Easiest way to slow down a 240v AC fan?
Replies: 8
Views: 5349

There is no super cheap method. What is reasonable depends on how much current your fan pulls. You can use series resistors of sufficient wattage to reduce the voltage on the fan, they generate heat though. You can use series capacitors to do essentially the same thing without generating excess heat...
by ferdb
Tue Jan 25, 2005 2:33 pm
Forum: Fans and Control
Topic: Will resistors really do the job?
Replies: 29
Views: 9838

Putting zener diodes in parallel to share the power dissipation is a bad idea. Because the breakdown voltages won't be exactly the same one of the diodes will hog all the current and get hot and the other will not. Just get higher wattage zeners, or if you must, put two in series that are half the v...
by ferdb
Sat Jan 08, 2005 2:05 pm
Forum: Fans and Control
Topic: 120x38mm AC fans - the ultimate quiet 120mm fan?
Replies: 55
Views: 42865

I'm using 1 inch standoffs and rubber grommets to mount them to the Radiator, but it would be nice to come up with something a little better in the way of support and isolation.
by ferdb
Fri Jan 07, 2005 12:13 pm
Forum: Fans and Control
Topic: L1A heatsink fan longevity? any fail safe options?
Replies: 9
Views: 3249

Undervolted sleeve bearing fans last much longer than when running at full voltage. The primary mode of failure of sleeve bearings is the oil in the bearing gets spun out by centrifugal forces leaving the bearing short on lubrication and thus accelerating wear of the bearing surfaces. Lower RPM not ...
by ferdb
Fri Jan 07, 2005 6:52 am
Forum: Fans and Control
Topic: 120x38mm AC fans - the ultimate quiet 120mm fan?
Replies: 55
Views: 42865

I've been caught up in other demands lately, but I did receive two of the A2123HST fans from pdf27 (thanks again). I mounted them on a Black Ice Pro II radiator and did some rpm/airflow measurements and comparative noise tests between them and a Nexus 120 and Sunon 2123xst at similar rpms. At the sa...
by ferdb
Mon Dec 20, 2004 5:42 am
Forum: Fans and Control
Topic: 120mm recommendations? I don't need silent, just quiet.
Replies: 3
Views: 1572

Get a Fanmate for $4 to control the fan speed. The Nexus and Globes are pretty close to the best airflow vs noise ratio so you aren't really going to do any better. Just put it in, and dial it up to the airflow / noise level you want.
by ferdb
Sun Dec 12, 2004 4:41 pm
Forum: Watercooling
Topic: CSP-750 pump failure.
Replies: 6
Views: 2572

CSP-750 pump failure.

The CSP750 pump I had running for the last 2 months or so failed. Apparently the shaft seal leaked, the coolant seeped into the motor cavity (and then out the wiring hole) and finally the motor failed. I have a spare CSP750 that I've put in the machine (which makes a lot more noise than the other CS...
by ferdb
Wed Dec 08, 2004 6:42 am
Forum: Fans and Control
Topic: SilenX crusty?
Replies: 23
Views: 13124

If you can just barely hold your finger on something to a count of 5 it's roughly 70C. Unless you are a waiter at a Mexican restaurant, in which case it would be 140C. Honestly, I have no idea how they can hold those cheese enchilada plates in their hands. They are clearly of the Nexus 6 generation.
by ferdb
Sat Dec 04, 2004 9:28 am
Forum: Power Supplies
Topic: Noisey Super Silencer 350
Replies: 20
Views: 4429

just order the Nexus. the panaflo bearing noise is hit or miss
by ferdb
Thu Dec 02, 2004 4:20 pm
Forum: Fans and Control
Topic: Silentx 80 mm (14dba) vs Vantec Stealth 80mm(8025 21dba)
Replies: 24
Views: 6633

I didn't mean to compare the Silenx price to the Nexus price, but rather the Globe fans which they perform very similar to. The globe 120's are 1/4 the price of the Silenx. CFM is directly related to RPM under Free air flow conditions. If you halve the RPM the CFM drops by half. This is no longer tr...