Home Theatre cooling

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757 posts

Ultimate Geek

#397201 29-Oct-2010 10:19

timmmay:

That link is to an IDE/USB adapter, but I get your idea about noise, controllers, etc.

The pre-made kit is sounding better and better, it'd avoid most of the problems mentioned.

The kit contains the power supply. The USB/IDE part you can throw away. When I built my fan controller for my modded Xbox 360, I needed the power supply and I couldn't find just the psu by itself.

You could simply use something like a simple Zalman fanmate if you aren't fussed about temp monitoring.

The ebay pre-built unit doesn't mention 230V either, so I'd be asking for clarity on that before pulling the trigger.

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timmmay

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#397222 29-Oct-2010 11:04

Thanks for all the thoughts and advice, I appreciate it.

The ebay kit does support 240V, I did ask. Those fans are rated 21db at full speed, so probably <18db at half speed. It comes pre-wired, selectable fan speed, with a power supply, nice connectors, digital thermostat, etc, for US$130 shipped. I think that's reasonable, and really easy, so I suspect i'll go for it rather than diy. DIY would be a little cheaper, and more work, and I value my time over small amounts of money.

Asmodeus

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#397268 29-Oct-2010 12:10

I have a 300mm fan on one of my pc cases and it is basically silent, certainly quieter than 120mm fans or smaller. It does mean you'd need a foot wide hole in the back on your cabinet tho... :)

timmmay

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#397279 29-Oct-2010 12:25

300mm is pretty crazy!

illicit

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Ultimate Geek

#397293 29-Oct-2010 12:48

I've done a few fan setups for customers a/v cabinets.

12v 120mm PC Fan
USB Cable

Cut USB cable, solder red and black wires to fan, heatshrink, DONE.

Plug into a device with a USB port and it will switch on/off with the device (eg TV), and only uses 5v so the fan runs quietly but still more than adequate for cooling

timmmay

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#397311 29-Oct-2010 13:11

That sounds like a nice, simple, effective way to do it illicit. A TV USB port sounds like a good option, because in practice if the TV's on the receiver will probably be on too. I'd want to run two fans, as it's a two section cabinet, but I think the USB port's 500ma can handle it.

DIY is quite a bit cheaper... $30 for a good 180mm fan, $5 for a USB cables, heatshrink, cable, and a little time, and i'm done. The other option's a thermostat controlled unit from the US, for about $180, but it's a neater solution.

richms

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#397322 29-Oct-2010 13:33

If the amp has a 12v trigger out on it, you can just use that into a mosfet to switch the fans off and on (low voltage side of the power supply) or a solid state relay to control the high voltage side.

The power supplies like the one included with the IDE adapter kit are a dollar on ebay plus another dollar to ship to NZ, that should tell you what the quality is like.

I got a few hoping to use for a project, but they are unreguated, load up the 12v side and the 5v goes up heaps, and also they are very very noisy, both in DC output, RF noise, and crap they put back onto the AC line. Not what I would be wanting to wedge in by my stereo etc.

Also I doubt they have any form of actual compliance certs, just the marks printed all over them.

If you really want to try, I will send you one I have here.

Richard rich.ms

timmmay

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#397329 29-Oct-2010 13:41

I have no idea if my amp has that, it's an Onkyo TX-SR508. I think illicit's idea is the best so far, using the USB power from the TV.

elldizzle

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Master Geek

#398943 2-Nov-2010 07:02

Due to suggestions from this thread and others Iv'e read, I am now in the process of sorting out some cooling myself. I had a 120mm 12VDC case fan from an old build a few years back. So on the suggestion from a poster here I cut the connectors off and first wired it to a 12V power supply wall wort. And it worked perfectly. So I decided to see what it was like with half the power, so I wired it to an old USB chord. Plugged it into the USB port on the back of the T.V and worked perfectly. No real change in speed or airflow. So as a little experiment I just sat it in the cabinet side blowing at the side of my amp (still crudely wired and everything). And I was surprised how well it kept everything cool. After an hour or so of watching select movie scenes and playing with some calibration. The Receiver was noticeably cooler than before.

So now Im gonna get the jigsaw out and mount about 3 fans in the back of the cabinet. My questions are Could I wire three off one USB port, connected in parallel?... Or would a 3 port USB hub be better?....Or exactly the same?.... Or am I best wiring them too a 12VDC wall wort in parallel?.......The only drawback being it wont turn on and off with my display...

timmmay

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#398951 2-Nov-2010 07:49

Good to hear about your success Ell. My reading suggested a USB port can supply 0.5A, so a multimeter should answer that problem for you. I plan to wire two fans to my TV in parallel.

illicit

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Ultimate Geek

#399079 2-Nov-2010 13:03

elldizzle - try just two fans first, I think you'll find it enough.

most fans only use about 0.15 or 0.20 amps so two should be fine but check the box for the fans, they usually have the amperage written on it

timmmay

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#399082 2-Nov-2010 13:08

The fans I got draw (Evercool 140mm) draw 0.3amps at 12V. My vague memory of uni electronics is as voltage drops so does current draw, so 5V suggests a 125ma draw.

richms

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#399105 2-Nov-2010 13:54

Ohms law isn't relevant for a load like a fan, If the power is constant as no change in airflow suggests, then current will go up as voltage drops.

Modern fans have a proper speed controller in them with a 4th wire to control the speed, If you lower the speed thru the 4th wire, then the current will drop, but speed controlers will be lengthening the on time for the windings inorder to keep the speed.

Richard rich.ms

timmmay

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#399148 2-Nov-2010 15:08

So, given I have the fan above, should I just connect the two power wires to the USB power and not worry about anything, or should I be trying something else?

richms

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#399167 2-Nov-2010 15:29

Check the current with a multimeter, the USB port will definatly supply 500mA, but will probably be able to supply a lot more since they expect people to plug in non compliant things like external 2.5" harddrives etc. But you dont know if there is any over current stuff on the port or if you are possibly going to toast it.

I would use a seperate power supply and just switch it from the USB port with a transistor or solid state relay.

Richard rich.ms

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