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Entertainment Center Cooling?
skubalon asks: "I have a decent bit of audio equipment for my home theatre. All of it is housed within a wooden entertainment center with a glass door. This doesn't do much for keeping my system cool. I have tested and found that the ambient temperature in the cabinet does not go higher than 100F (37.7C). I know that my receiver has a thermal shutoff, but is this safe? What have other readers done about cooling home audio equipment?"
Don't worry about it, the temperature is nice and low, and is unlikely to overheat unless theres a malfunction. The thermal shutoff too, is only likely to come into action as a result of malfunction, not as a result of normal operation.
Ambient temperatures of 100F aren't hazardous to most consumer electronics. In terms of durability: Given exclusion from severe catastrophic failure syndrome catalysts such as lightning strikes and 2-year-old children, anything in your cabinet which doesn't rely on moving parts is very likely to outlive you and a number of your descendants.
That said, neither the bearings in your DVD player nor the VHS tapes you play are likely to be happy, long-term, with such elevated temperature.
Additionally, the properties of the individual components (caps, resistors, transistors) change with temperature, so well-designed analog electronics are engineered with a specific temperature range in mind. They'll certainly sound best when operated at whatever ambient temperature they were designed for, which is likely to be at or slightly above room temperature (72F).
The thermal switch in your amp is not likely to trip until the heatsink is justabout hot enough to boil water. It exists as a safety feature, like a fuse, to turn things off under abusive situations or in catastrophic modes of failure. It is not, in any way, a device intended to ensure proper fidelity.
My parents have a similar situation at their house. They've got a 36" Sony CRT, on top of a glass-doored Sony stand. Inside this stand resides all of the extra components associated with the TV - a DVD player, VCR, and DirecTV TiVo.
After adding an 80-gig, 7200RPM Maxtor to the TiVo, things would get hot enough inside of the cabinet that the TiVo would lock hard every couple of days.
They simply removed the glass doors, and everything has been rock-solid stable since.
I recommend you do the same.
Not only will your components be more accessible, you won't need to worry about things being too hot. It's also free.
In my own living room, I solve the heat problem differently. I've got the line-level (minimal BTW/hr) stereo components stacked neatly on a shelf, the TV on its own seperate stand along with the PSX and DVD player, and a fan-cooled power amp in its own rack back in the far corner of the room, hidden behind a plush chair.
By spreading things out and avoiding confining furniture, heat becomes a non-issue. And I also get to keep the more dangerous components (the ones with volume controls, capable of producing dangerously-loud, eviction-level radio static) up out of reach of my 2-year-old daughter.
If none of these solutions are appealing, simply install a largish, slow-moving fan near the top of whatever cavity houses your AV components, exhausting air out the back. Maybe something like this would do the trick. If such an arrangment turns out to be too loud, wire a rheostat in series with it to slow it down even more.
You could also use a low-voltage DC fan, but it'd take all of the fun out of it and require the use of a seperate power supply.
Whichever the case, the purpose here is not to actively cool the components, but to simply provide a mechanism for exchanging the stale, warm air inside of a cabinet with cooler air from outside, be it by convection (avoidance of enclosed cabinets and glass doors) or force (a fan to push things around).
It won't take much.
Kid-proof tablet..
I have a similar set up, and I have two small children which means that taking off the door is not a viable option. I tried installing a standard muffin fan, but it vibrated the wood and made a lot of noise so I removed it (though a slow fan might have worked better). I did leave the fan hole open, though, and found that this made a big difference in the ambient temperature inside the cabinet.
So I suggest that you use a hole saw to cut some large holes (the larger the better) in the back of the cabinet. Just don't remove so much wood that it causes structural damage. :-)
The URL links to DigiKey don't work. Would you mind providing the part numbers?
The glass door is probably there for 2 reasons: aesthetics, and keeping the ambient noise level of the room to a minimum by attempting to keep noise inside the cabinet.
My suggestion: Cut a small hole in the backing of the cabinet and put in a small fan (standard 80mm case fan might work, but ya might want to find something a little larger to move more air.) It'll increase the noise level of the room by the noise level of the fan, but that will be less volume than taking the glass door off.
Now, I'm expecting someone to come along and respond to my post about how evil fans are and that he should be using water cooling...
Another suggestion, but this will increase the room noise and cut off any IR capabilities, is to put shuttered wood doors on the cabinet. These will allow at least some exchange of air, but unfortunately will block any IR remotes.
I've always thought an elegant solution would be to have an in the wall ventilation system sort of like those built in vaccumes. The noise would be in the basement, and you'd just hook up a hose that would draw air through whatever component needed air, and exhaust it elsewhere.
Use a 48U rack with a cooling fan setup in it.
You'll still have your glass door, comfortable tempatures, and it'll be a GREAT conversation piece.
Immerse it in mineral oil!
;)
It will stay cool *and* you can get a second story onto slashdot when you do it!
*everything* is Orwellian to cats.
Work with the hot air. Remove hot air from the top using holes and/or fans. You might want to put the fans in a separate box sound proof or outside the room with a hose to the enclosure. Have vents a the bottom also maybe with filters to keep the dust out. Remember to make sure there is are flow from shelf to shelf.
It can be hard to know what to do with all those components these days. Now that you've overclocked your graphic equalizer, CD player, and DVD player, how do you keep them cool?
How about a nice big refrigerator? You ought to be able to get an old one for cheap. If you're handy with tools, you can cut a hole in the fridge and make a plexiglass window (Otherwise, watch the overclocker hardware sites, as they'll undoubtedly start selling pre-modded fridges). That way, you can keep your TV cool too. Throw a few colored lights in there, and you've got quite a geek setup. As a bonus, you can keep a few beers cold and within easy reach.
Donate background CPU time to fight cancer.
If you don't want to take the door off, use either vents or fans. Pre-made vents and fans specifically for entertainment centers are available from several suppliers, including this one.
Try these vents, or these, or these. Put some vents at the bottom and some at the top along the sides or the rear wall and the case will draw cool air from the bottom while the heat rises out of the top vents. If you need still more cooling, add a power fan which includes a dust filter.
Two different setups I have gone to Radio Shack and purchased a pair of 6" fans. I also went to Home Depot to get little rubber grommets to use in mounting the fans to the entertainment center (prevents vibrations and rattling noises). Use a coping saw or large hole saw to open the vent, and use a small bit for the four holes that screw the fans to the cabinet.
I Place one fan blowing in, at the back of the center, right behind the major equipment. I place the other at the top of the cabinet blowing out. Both times I've been lucky enough to have a receiver/amp that has one of those piggy-back plugs in the back - you just plug the fans into that and you have controlled power, as well.
I find that these fans are just quiet enough for general use, but audiophiles may not agree.
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I bolted 4 80mm case fans to the back of the entertainment center, daisy-chained their molex connectors, then soldered a 120VAC->12VDC converter to the chain. Then I plugged the adapter into the power outlet on the back of the AV Receiver so they spin up when the power is on. A bit loud, but really does the trick.
Don't forget to make the fans do air EXCHANGE, not just blow over the components - one facing each direction on a shelf will ensure that the hot air is exhausted and the cooler air is brought in.
Also, component placement is important - heat rises, so put the hottest component (usually the amplifier or receiver) on the top with a good 6-8 inches of clearance above it. Cooler or less-frequently used components go closer to the bottom of the stack/on a lower shelf.
I also have a PC in the entertainment center, so I extended a fan header from the motherboard to the outside of the case and did the same with two smaller fans.
The TiVo in the cabinet doesn't get about the high 40's (Celsius), and I don't have lm_sensors on the PC yet, but it's not terribly warm in the cabinet.
There's an easy answer. Buy an axial fan that is meant for 205 volts AC operation. They run silently at 115 volts AC, but still move an acceptable amount of air. Alternatively, it might be possible to buy a very quiet 115 volt AC fan and use it at its intended voltage, 115 volts. Fans meant for 230 volts AC may work, also.
I have no experience with this model, but this is the kind of fan that I use: Whisper AC. The 29 dBA noise level of the WR2A1 model may be low enough. A fan that is very quiet and is used at a slightly lower than rated voltage may work also.
I bought 5 axial 205 volt fans from a local surplus electronics dealer. They cost me $3.95 each. They are expensive fans, but were being sold cheaply because they were the wrong voltage. Who would want a 205 volt fan?
I use a fan on top of the vent holes on my stereo power amplifier. I also use a fan on top of each of my computer monitors. Heat is the enemy of electronics. Heat accelerates chemical change; if it is working now, you don't want changes.
You could also use a 12 volt DC computer cooling fan and run it at perhaps 7 volts. An old 6 volt DC wall transformer (wall wart) meant for some old appliance might supply the correct voltage at the small load of a fan. (At small load, the output of a transformer/rectifier wall wart combination is higher than the rated voltage, sometimes considerably higher.) If you use a resistor to lower the 12 volt output voltage of an old computer power supply, remember that the resistor generates heat, and should be outside the stereo enclosure.
Stereo entertainment center enclosures have have a small vent at the top of the glass door in front; the glass does not come all the way up to the wood. If you put an axial fan at the bottom in back, blowing in, you create flow-through ventilation that is helped by the tendency of hot air to rise. Stereos don't require much ventilation; it is the completely dead air of an entertainment center without forced ventilation that causes the problems.
If you use a fan on top of a computer monitor, get a block of foam rubber. Put a fan-size hole in it and glue it to the fan. The foam rubber will hold the fan on the sloping top vent holes of the monitor with friction.
The big problem here is that the entertainment center manufacturers don't design a quiet fan into their products. These fans are VERY cheap when bought from the Chinese or Taiwanese fan manufacturers in quantity.
You're taking a gamble if you don't do anything to lower the temperatures of your components. Some quiet squirrel-cage style fans mounted appropriately can circulate enough air to lower temperatures considerably (20degF higher than ambient is likely attainable, of course depending upon the internal layout of the cabinet).
Use more, larger, slower-turning fans to keep things quiet. Baffles also help reduce the noise while only minimally impacting airflow.
I can't count the number of satellite TV receivers I've rebuilt, because they were kept on top of the video recorder, in a glass-fronted cabinet, and switched on all the time... The PSUs just fry up in weeks.
Yes, I know about shaded-pole motors. Yes, it would be better to have a very, very quiet fan that was designed for the operating voltage.
However, running these fans at less than the rated voltage works. There are two running now in the room in which I am working. They've been running for at least 7 years, except when all the power is turned off to the monitors. There is another that I've used for about 10 years, that now happens to be off. The idea works, with no drawbacks. The fan motors do NOT get hot, for the obvious reason: The fans cool them.
She's also very interested in the computer, but her idea of using the mouse is to pound it on the keyboard or floor. If I leave them "unprotected" for even a second, she's there pounding on it. The keyboard is holding up well (have to stick a key back on now and then. The mouse is working, but there is some broken bit rattling inside. Optical mice are great though, no amount of cruft or slime seems to effect them.