Cooling the HT cabinet with a computer fan

Discussion in 'Home Theater Projects' started by Alex-C, Jul 22, 2006.

  1. Alex-C

    Alex-C Screenwriter

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    Can this be done without a computer power supply in the cabinet ?

    I have done this with my computer desk...adding a separate computer fan outside of the computer, attached to a part of the desk to help the air flow out; it gets really hot in there especially in the summer, etc. etc.

    My HT cabinet gets really hot too, my denon 3806 just blazes, so I wonder if it would be possible to cut a hole out the back of my wall unit where the components are and attach a fan to help get the air out of there.

    I am really only wondering about how to power the fan. The rest of this is rather easy.(getting a cheap fan, maybe one with some lights on it, attaching it to the back, etc.)

    I dont know why this comes to mind today (its 114 degrees outside and inside my house is only getting so cool with the A/C running, above 80 !)
     
  2. Seth=L

    Seth=L Screenwriter

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    Yes it can be done with out a computer power supply. If you have an old ac adapter laying around you can use it to power a dc fan which is what they use in computers. You just have to be sure that the power output of the ac adapter doesn't exceed the limits of the fan. for instance if you have a ac adapter that outputs 12v at 300ma and you have a fan that can take up to 6v at 500ma the fan will fry more than likely unless it is underated but I wouldn't take any chances. the way to make sure the fan will accept the feed is to multiply the voltage of the ac adapter by it's amperage (take into account your decimal places 300ma is .3 amps) then do the same steps with the fan if the number you got from the the ac adapter is greater than the number you got for the fan then don't use that fan.

    If you don't have a ac adapter you can likely get one from radioshack.

    Hope all this helps.

    Seth=L
     
  3. chuckg

    chuckg Supporting Actor

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    Let me try to add some clarity to that response.


    The DC adaptor VOLTAGE should equal the fan voltage. nearly all computer fans are 12v, though there are some at 5v.

    The DC adaptor CURRENT shoud be equal or larger than the fan current. I would guess that 300 mA (milliamps) is plenty enough for any fan.


    A 12v 300mA DC adaptor should be less than $20 at the Shack.
     
  4. Seth=L

    Seth=L Screenwriter

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    Chuck if a ac-dc adapter is rated at 6 volts and 300ma and the fan is rated at 12 volts and 150ma wouldn't that be a working combonation, because i have a fan rated at 12 volts and 120ma powered by a 7.2 volt and 180ma adapter that works just fine? (I'm not going to start a fire am I?)

    Seth=L
     
  5. Seth=L

    Seth=L Screenwriter

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    OK I just finished doing some research on this and found this I there is a 12 volt fan and a 12 volt power supply (ac-dc adapter) and the current (amperage) that is output by the supply is higher than that rated on the the fan ex.(300ma power supply and a 200ma fan.), then the fan WILL FRY and could possibly create a fire. This is physics you can not force more power into something than it can take. That would be like trying to put 50 psi into a bicycle tire that can only handle 30 psi it would obviously and certainly burst.

    Under powering the fan does not present a problem. Just like running a hose with the valve half open it isn't going to damage anything.

    Seth=L


    I am here[​IMG]
     
  6. DelRay

    DelRay Stunt Coordinator

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    I'm also using an ac adapter. Mine is one of the adjustable voltage types. I'm using a 12 volt fan. When I first set it up I wanted to keep the fan noise low, so I kept adjusting the ouput voltage lower until I was satisfied with the amount of air being moved vs the noise level. Alex, if the Denon has switched outlets, you can plug the ac adapter into one of those, Then, the fan only comes on when the Denon is on.
     
  7. Seth=L

    Seth=L Screenwriter

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    I also have my fan plugged into my switched outlet with a voltage regulator though I generally leave the fan set to high because it is fairly quiet.
     
  8. Alex/d

    Alex/d Stunt Coordinator

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    If you wanted to be really cheap.. box fan. Then again, it would be loud... [​IMG]

    Also, when's the last time you took the cover off your reciever and blew compressed air through it? [​IMG]
    If you have a lot of dust inside it... a fan won't do much good.
     
  9. Seth=L

    Seth=L Screenwriter

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    GOD ALEX/D YOU ARE SO GOD DANG STUPID JUST GO DIE SOMEWHERE!!!!

    Just kiddin bud, but seriously he isn't going to use a box fan. That is just silly.
     
  10. chuckg

    chuckg Supporting Actor

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    Seth, don't take this as mean, but you are wrong. The adaptor in your example can provide up to 300mA. The fan will draw only 200mA, and that will be just fine. No fire, no trouble. The adaptor will not "force more power into the fan," any more than you can drink more water than there is in a glass. It is nothing at all like a bicycle tire. The adaptor will quite happily supply 200 mA to the fan, and have an easy time doing it.

    The trouble would come from having a fan requiring 300mA and an adaptor which can only supply 100mA. The adaptor in this case would get quite warm, and possibly burn out.

    The voltage on the fan and the adaptor should match. If the adaptor provides a lower voltage, the fan will probably run slower. If the adaptor provides a higher voltage, you could overheat the fan, causing it to burn out.

    I've been building electronic devices for 35 years, and do have some experience to back up what I am saying.
     
  11. Seth=L

    Seth=L Screenwriter

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    Sorry, I guess my source is also misinformed. Come to think of it the power supply I am using does get a little warm sometimes.

    Thanks Chuck,

    Seth
     
  12. SoCalSooner

    SoCalSooner Auditioning

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    If you really want it cooled and quit. Buy a fan with a "Sones" rating of
     
  13. wallandgrom

    wallandgrom Auditioning

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