Power supply for single PC case fan to cool AMP in a cabinet

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afe66

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Topic # 145433 17-May-2014 15:56

Dear All,

I have a Denon amp which the specs say must have 30 cm clearance above it for cooling purposes but I need to put it in a cabinet which will have only 3-5 cm clearance above it.

One cooling option are a small directional USB fan which I could drive using the USB port on the amp.

Second option is to use a case fan of some sort which would require a power supply. I could use an old pc power supply but that seems very bulky.
I also found a fan like what cools a laptop cpu ie sucks air from the underside and ejects it at 90 degrees. (only 2 cm tall)

Another thought I had would be to get a 12V 400mA power supply unit from Jaycars like use to drive a Roku or similar then get the cable and wired it into a modinex type connector ?

Is this reasonable ?

Other thoughts/suggestions are apprecated.

A.

Niel

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Reply # 1047216 17-May-2014 20:55

Any 12V power supply, but the fan might be a bit too noisy. Can run it off a 9V power supply. Just cut the wires, strip and twist together (noting polarity). Or better, use some cable joiners like insulation displacement connectors.

You can never have enough Volvos!

Dynamic

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Reply # 1047232 17-May-2014 21:11

I would be tempted to pull apart one of the laptop coolers that is powered from a USB connection so it can be powered from the amp and only runs when the amp is on. The fans will be low powered but should give plenty enough airflow to circulate the air.

"4 wheels move the body. 2 wheels move the soul."

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MikeAqua

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Reply # 1054288 27-May-2014 13:01

If you run it only when the amp is producing a lot of heat (ie working hard), you wont hear the fan above the speakers.

Mike

afe66

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Reply # 1054327 27-May-2014 13:54

I had a look at laptop coolers when in Singapore and wondered about putting the cooler above the AMP but wondered how effective it would be blowing straight up 4cm to underside of the cabinet rather than across. Then got distracted by finding the fan which sucked from underneath and blew horizontally.

( I now see your point that I could disassemble the fan assembly and position it at 45 degrees and utilise the USB power supply)

Over the last week or two I have left a small digital thermometer on top of the AMP to get idea of how hot it gets when not enclosed. Seems to peak at 33 or so.

I'm going to give it a couple more weeks to confirm what the maximum AMP temperature is before placing in cabinet and noting max temperature without cooling, then will try the small usb fan is then the ?laptop cpu cooler but that will require a 12v power supply

A.

PS why is there an inverse relationship between body size and size of cellphone screen in Singapore women..

illicit

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Reply # 1054969 28-May-2014 12:06

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What model is your Amp? Does it have a 12v trigger out on the rear?

I use that on my Integra amp to run a PC Fan

afe66

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Reply # 1054979 28-May-2014 12:20

Denon x3000 bought at Christmas.

Your thought sounds interesting, I think it does have a trigger at the back.
I'll try to dig out the manual as I don't know how trigger works..

(very happy with AMP, compatible with DD+ from W8.1 Netflix App on NUC HTPC)

Thanks

A.

afe66

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Reply # 1055869 29-May-2014 13:03

OK after a bit of looking the AMPs trigger out is 12V 150mA which is the same as the fan I bought which sounds optimistic (and also for several case fans I've seen).

So is the trigger actively supplying this voltage when ever its on or does it "spike" a signal then stop.

Do I just need to find a plug of the correct size and wire it to the fan so that when the AMP is on it goes or do I need to find some circuitry ?

A.

illicit

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Reply # 1056998 31-May-2014 11:17

12v Triggers are consistantly on - Just cut a cord off an old pair of headphones = 3.5mm jack & wire to fan DONE!

afe66

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Reply # 1057182 31-May-2014 18:58

Thanks.

Will getting the polarity wrong damage the fan or will it rotate in opposite direction.

A.

Dynamic

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Reply # 1057195 31-May-2014 19:59

It will rotate opposite but check the side of the fan for rotation direction arrow and ensure you are going the right way 'just in case' it affects the lubrication of the bearing or something silly like that.

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richms

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Reply # 1057199 31-May-2014 20:08

Wrong polarity will not turn the fan at all. None I have abused like that when case modding etc have ever had any permanant damage, just not turned.

Richard rich.ms

afe66

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Reply # 1132738 20-Sep-2014 14:45

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Final product working well. After a couple of months I might solder those joints.

Only one point of panic was when it was all connected up to the AMP and didn't work, was as richms mentioned, if the polarity if wrong the fan doesn’t turn (as opposed to rotating in the opposite direction).

amp cooler

3.5mm mono plug to a corsair case fan into the screen trigger of a Denon x3000.
Quiet, but also only turns when the AMP/speakers are going to cant hear it any way.

Thanks again to the above posters.

A.