Axiom Home Page Forums General Discussion Home Theater cooling hot receiver

I just purchased an Onkyo tx-sr805 receiver. I have it on a shelf in my TV stand. The stand is open on all sides and there is about 5 or 6 inches from the top of the receiver to the shelf above for the amp to breathe. The Onkyo 805 is replacing an Onkyo 502 so I know how the Onkyo's run warmer than other receivers. I never had any problems having the receiver setup in the same TV stand for about 4 years. The Onkyo 805 seems to run a little bit warmer, probably because it has a much beefier amp. I was considering adding an external fan(s) with a built in thermostat. Something like one of these.

http://coolerguys.com/840556082491.html (also has link to 2 or 3 fan version on this page)

or http://cgi.ebay.com/AV-RECEIVER-AMP-120m...1QQcmdZViewItem

How many fans would I need to do the job? Are these reasonably priced items? Has anyone else used these types of items?

Thanks in advance for any replies.

- Nick

I have no experience cooling amps but lots in cooling PCs. Extra cooling is always good but I will add one small caution.

If you are thinking about modding the box to add a new fan(s) into the chassis to compliment the already existing fan, there is one small danger. Adding a more powerful fan can sometimes push or suck so much extra air through the existing fan that it ends up moving faster than it's motor wants to turn it and it can possibly burn it out. Some fans are sensitive to this while others, not as much.

You have to give a little thought to maintaining a balance of air flow in verses out when you go with multiple fans. Other than that, it can produce great results.

If you are thinking of adding fans externally to your shelving, then no problem. Find something that balances strong flow vs. noise. More air flow = more cooling but you don't want to introduce too much noise either. Again, a bit of research will get you a strong but quiet solution.

Murph,


The fans that I am considering in the links are ones that sit on top of the receiver and help suck out more hot air than can naturally flow out. The Onkyo 805 doesn't have any cooling fans so it shouldn't be a problem just adding one, two, or three external fans. The fans that I was looking at in the links have thermostats that measure the air temperature and kick on when the receiver gets hot enough. So, installation is just a matter of setting the fans on top of the receiver and plugging them into an outlet, just like in the picture on the ebay link. It's just that these fans seem a bit expensive. I was wondering if anyone has seen this same type of fan setup cheaper somewhere else? As you suggested I want the fans to be quiet. How many of these fans would be sufficient (without being overkill) for the receiver?

- Nick

I had an AC powered fan for a very short while. It was a 12cm fan from Rat Shack, and it was incredibly noisy. YMMV.

These should work fine to keep the 805 cool.

I use a fan to cool my Denon 3808 similar to the ones you're looking at. Mine is mounted on the back of my AV cabinet--you can see it in the third picture of the Wagner home theatre in the gallery section. It's plugged into the receiver so when you turn it on, the fan comes on. It's whisper quite and makes a big difference in the cabinet. I was told that if your receiver is too hot to touch, or it shuts off on it's own, then it's just fine as is. However I figure $50 is a small investment for a $1500 AVR.

Based on my extensive experience cooling PCs...I can say that you probably want 2 fans. One pushing air in, and one pulling air out (or visa versa if they are mounted internally). That's the standard computer chassis setup, which is a bit larger than an AVR, but produces less heat.

You want high CFM, low RPM fans, anything under 1000 RPM will be fairly quiet, anything over 1500 RPM starts to get noisy, and 2500+ RPM is just crazy talk. For PC cooling I'm a big fan of Scythe fans. Typically I'd hook my case fans up to a fan controller that fits in a drive bay and has little knobs with digital readouts I can turn to adjust the fan speed. That way I can buy 3000 RPM fans in the event I need the extra cooling, and just dial them down to 1000 RPM or turn them off entirely when I don't want the noise. You can get a top of the line 120mm fan for under $15, so most of the price of those kits is going towards the thermostat and associated wirings.

If you could get a setup like that, with manually adjustable fans, it would probably be ideal, and cheaper than a built in thermostat. The thermostat is nice, but I don't tend to trust them, just like I often don't trust thermal sensors in PCs. If you can buy the thermostat or speed controller separate, I'd go for that. This will probably save you a bit of money over a kit, and you can get much nicer fans.

There are lots of good choices for high flow low rpm fans. Yate Loon and Noctua are another two that come to mind.

If you want to go full bore pedantic and find the absolute best for you check out this site on silent computing.

Nick, if you're gonna mod this thing you gotta at least cut a hole in the chassy somewhere.

Second on the Yate Loons. They have some very nice low RPM silent fans with high CFM and a low profile, and are pretty cheap to boot.

If your cabinet is open on all sides and with 5 to 6 inches on top, I'd guess that you'll be fine without needing additional cooling.

Has anyone tried anything like this before?

http://www.sportsimportsltd.com/19ramocofans.html

Or this one?

http://www.sportsimportsltd.com/2fanelcocoun.html

I did exactly this for my (first Marantz then 3808) I bought my silent PC fan from http://buyextras.com/cacoso.html and bought the AC (to molex) adapter for the DC fans from the same sight. Works like a charm. The only other thing I did was to buy those fuzzy furniture protectors from Home depot. this way, it doesn't rattle at all.

Nick, if as you say the 805 is just running "a little bit warmer", e.g., no smoke and flames, there wouldn't appear to be a compelling reason to bother with a fan. Running hot may reduce the long-term service life, but shouldn't be a matter of significant concern if the unit is operating well.

Agree with all. If there are no internal fans, any solution should be safe to do. Just check for dust buildup now and then as it will be sucking in more dust than usual and eventually, the dust buildup can defeat any cooling you add. I'd also probably agree with running it a while, as is, before I spent any money.

ON the other hand, I think you should go out and build the first water cooled amp. Trick it out with alien green LED lighting and fluorescent coolant. Mod the case with a see through panel in the shape of an Axiom symbol so you can see all the glow bling. Have the LEDs tied to the thermostat so the more it cools, the brighter the glow.

OK, maybe you shouldn't do that. But if you do, we want pictures so we can make fun of you.

Good luck watching a movie in the dark with that thing!