[brschmid]

Quote:

Originally Posted by PinkFloyd This may sound stupid but why not either replace the fan with a quieter fan or take the existing fan to bits and grease the bearings? There's no point in slowing the rpm of the fan as it's there for a purpose..... to dissipate heat, if it's noisy then address the issue with a new fan / noise dampening.

there is many reasons as to why quiet a fan down. mine is only noisy because of the amount air it moves, i don't need it to move that much air, i just need it to draw out some heat.

 

[aos]

Adding a resistor in series (by the looks of it I estimate 5W) is a common way of slowing down fans, used by e.g. Zalman. Actually I buy their fans, then just use the adapter (which is basically a male and a female 3-pin header, with a resistor in between) and use it with a different fan (Zalman's isn't very quiet) because - when on sale - it's cheaper than me making them (if you count your time). I don't see why should you use LM317 - and besides you should rather use 780x series anyway as they require much less parts and are cheaper. Add a resistor to something like Panaflo and you'll get practically inaudible fans.

 

[flecom]

those little zalman boxes with the tiny knob are just LM317 regulators, you could get one of those at compusa and there you go done

 

[ooheadsoo]

Thanks for the tips, guys.

Making your own circuits sounds like an adventure, but I'm also thinking that either the resistor method or a nice panaflow would probably be the easiest. I'd have to buy or borrow a cheap multimeter to measure the current voltage or current draw, so I may end up just getting a low rpm panaflow once I unplug everything AGAIN and open it up AGAIN and measure the diameter of the fan. I wish I had an extra unit to tinker with

 

[randytsuch]

Quote:

Originally Posted by ooheadsoo Thanks for the tips, guys. Making your own circuits sounds like an adventure, but I'm also thinking that either the resistor method or a nice panaflow would probably be the easiest. I'd have to buy or borrow a cheap multimeter to measure the current voltage or current draw, so I may end up just getting a low rpm panaflow once I unplug everything AGAIN and open it up AGAIN and measure the diameter of the fan. I wish I had an extra unit to tinker with

Did you look at the fan? They usually have labels, which will tell you the operating voltage, and either current draw or power consumption. You might have to remove the fan to see the label, and I won't guarantee the information is there.

Otherwise, I have two meters, and work in WLA. Could loan you the cheap one for a little while, if you wanted.

Randy

 

[13405]

Firstly, you must ensure that whatever you do, it will be keeping the piece of equipment within the thermal guidelines.

The best solution would be to buy a quieter fan, possibly one with fluid bearings. If you read up on silent computing there is a great resource of information on these. try http://www.silentpcreview.com

Secondly try isolating the mechanical noise/vibration. There are many rubber/foam mounts specifically to do this. If you are creative enough im sure you can do you own version of isolating the vibration from the case - using elastic/foam.

If these measures are still not enough, slowing down the fan is the next choice. It can be acheived in many ways -
1/ using a manual fan controller (with a knob to control speed)- OTT for this application, also may have mounting problems
2/ using a thermal fan controller - there are some on the market which are extremely cheap and seem almost ideal for this app. look around.
3/ Manually reducing the supply - you can use diodes/resistors or regulators for this. There are more complex solutions, but IMO a resistor is adequate. To calculate the value (ask asked):

R = (Vin - Desired Vout) / current drawn

Typically, for example, an 80x80mm fan will run at 1 - 1.5W at 12V. This means assuming it draws 1.2W: 1.2/12 = 0.1A

If you want to run the fan at 7V, (12-7) / 0.1 = 50 Ohms

This does not always hold true due to the way the fans operate, but is a base for a good starting value. Try it and see.

Running a fan at 7v will give a large drop in noise, and generally gives an acceptable level or performance. Be careful if the fan is a low-RPM type. Running the fan at 5v may cause problems, depending on the fan - sometimes this is not enough for the fan to start up.

I would guess your fan is 60x60mm or 80x80mm - the other standards are 40x40, 92x92, 120x120. It is unlikely it is one of the more beculiar physical variants, in which case it may be harder to find a replacement.