Another cooling fan question. (1 Viewer)

[David Preston]

Which would be the better way to mount a cooling fan for my receiver? It is enclosed in a ET center. Would it be better to have it blowing across the top of the receiver or blowing out the back of the cabinet to get the hot air out? I thought it would be better to have it blowing on the receiver not directly into it or out the back becuse it don't get that hot in the cabinet just the receiver get hot. Another question how do you hook on of the little fans up. I want one of the Radio Shack or Parts Express fans but not sure how to plug them in to work. Thanks in advance.

 

[TomCW]

Generally it works better to have the fan mounted at the top, blowing out, as hot air rises. If you use a 12 volt DC fan, you can use a variable power adapter (RS 273-1667 would work) and set the voltage for the speed you need for cooling while keeping the noise down.
Tom

 

[Bob McElfresh]

You have to think in terms of a circle. You can:

- force cool air in the bottom and let warm air escape out the top.

- force warm air out of the top and let cool air in at the bottom.

Assuming you have the proper space above your receiver, either technique works. When in doubt, blowing the air over the receiver to force the warm air away is likely the safest.

The easiest thing to do is buy a small AC fan like a clamp-on fan or small box fan and just put it behind your rack blowing into an opening. These little fans can be found at the drug/department store.

(You DO have your receiver on the bottom shelf - right?)

If you want to buy some "muffin" fans, get the square ones from Radio Shack and be sure to buy the 12 volt DC ones. Radio Shack sells a neat little system of "battery eliminators" with interchangable plugs. Get the "Test Lead" and the power supply that allows you to adjust the voltage from about 6-15 volts. Wire up the fans with 12 volts, then check the noise levels. Turn the voltage down to reduce the fan speeds so they are not audible during quiet parts of a movie.

Good Luck.

 

[David Preston]

Thanks my receiver is on the bottom with about 10" of clearence above it and 1" on the sides. The back has to stick out a little so I cut a hole just big enough for the receiver to stick out. I was thinking anbout cutting a hole just big enough for the fan to fit in above the receiver to blow across the top. Hey Bob how small of a fan can you find at the dept or drug store. I want something small.

 

[Bob McElfresh]

If you want small, you can pick up 6" Muffin fans at Radio Shack for about $15-$20. Cut a hole in the back of your rack to frame the fan and attach with screws. But you have to wire up the 120v AC to it yourself.

If you are not comfortable with this, the pre-built fans are your best bet. I've seen mini box-fans that are about 9 inches, and other "personal cooling" fans that are smaller still. It's funny, but cheap fans are about $12. The really small fans run $30+. You just have to run out and look at your local drug stores or department stores.

But hurry. Summer is here so the selection is good, but these are seasonal items so they disappear in about a month.

When the temp reached 100+ at my house, I just bought a "turbo" fan for about $15 and put it behind my rack blowing over the receiver. I have no back on my rack because I play around so much back there.

 

[anth_c]

If you are looking at 12 DC fans, you should check out the computer sites such as 2coolteck.com:

http://2cooltek.safeshopper.com/23/cat23.htm?582

They have tons of fans in sizes less than 4 inches. They also list the cubic feet per minute (cfm) and the sound level of each model.

Note: the Panaflo fans (actually made by Panasonic) are well regarded in the computer circles for their cooling to noise ratio.

 

[Bob McElfresh]

Yes, an old PC power supply and PC cooling fans can create a neat cooling system.

For about $24 at Frys I found a PC Temperature Monitor. This thing has 4 thermosensors and 4 power cords for PC cooling fans. It has a blue front-panel display with controls that allow you to pick a temperature for each of the 4 sensors. When things get too hot, the unit turns on an associated fan to cool things down. The front panel includes a real-time temperature display and is sized to slip into a drive-bay in a computer.

I also found a similar drive-bay unit with simply 4 knobs to control 4 fans with independent speeds for each. The controller was about $15

(Note: I did not find these for a HT cooling application. I was playing around with the idea of controling the air into a BBQ for temperature control over long 15-hour cooks.)

The best part is everything just plugs together with the standard PC power connectors. Very handy if you dont want to mess around with bare wires.

 

[Luis_RC]

I have a couple of PC cooling fans on top of my receiver, blowing out, and powered by a variable power adapter exactly as TomCW suggested. It works great The voltage is set at just 4.5 volts, and the fans are inaudible; except when up close and nothing is playing.

My recommendation would be to get some good standard 80 mm PC fans (Panaflo, Sunnon, Delta, Pabst, etc), or larger (120mm), and run them SLOOOWW. Don't get a small fan since you'd have to run them really fast, and *noisy*, to get the same airflow.

Look at the link provided by anth_c

 

[Ben_Ly]

Um, actually, you shouldn't have your computer on the bottom shelf if you want the best performance. If you think about physics, hot air rises and your receiver produces the most amount of hot air. To maximize performance you want your receiver on top that way its hot air doesn't rise into the other components.

 

[Bob McElfresh]

you want your receiver on top that way its hot air doesn't rise into the other components

This is a common misconception.

As the heat moves away, it cools so by the time it reaches the second/third shelf it's warm, but not hot.

But heat needs a path to escape to (think of water in reverse). Putting the receiver on the top shelf of an enclosed cabinent is like putting a blanket on it - no place for the heat to flow. You NEED the shelves above the receiver for venting/chimney effect.

And the receiver on the bottom is better for stability, and cable management.

 

[Simon Ngan]

While on the topic, I'd like to know your opinion on blowing air to the equipment or sucking warm air out of the equipment.

I have a Primare P31.7 Processor and it runs fairly warm even on STANDBY. At the moment, I have a 120mm Vantec Stealth case fan connected to an universal wallwart with 7.5V. It runs very quiet and I use a filter on the fan so it will not blow dust to the processor.

However, I'm not sure if sucking hot air out is more effective?

Thanks,

Simon

 

[MikeTz]

David:

I've had excellent luck with the 115 Volt fans available at www.markertek.com (search on "fan" at the site and click on 4.5" Orion muffin fans). If you pick one of the quiet fans (22dB or 25dB) and allow them to blow over your amp and out of your cabinet, your unit will run cool and safe. Markertek also makes cheap 115 VAC plugs for the fans available on the same site.

Good luck.

MT

 

[Bob McElfresh]

I'd like to know your opinion on blowing air to the equipment or sucking warm air out of the equipment.

Well, I'm one of the guys who scratched his head over thermodynamics as I found it to be counter-intuitive.

I'd have to say Blowing air across the top of the receiver is the better choice over sucking air out the top of the cabinent.

My reasons (subject to debate) are:

- The fan immediatly pushes the warm air away from the receiver which is the main problem

- The fan can be filterd (good choice Simon ) which reduces dust moving into the cabinent. Venting air from the top means air must come in from cracks in the cabinent which also pulls in dust, dog hair, etc.