SPCR

Hello,

Hopefully this is in the right place.

I have been looking around the internet for any expertise on killing the fan noise from my 5.1 receiver. I could find nothing specifically geared toward audio electronics, so I figured I would ask you all.

I have a cheap RCA 5.1 surround sound receiver. I didn't realize when I bought it that it had a fan. The fan is intolerably loud (the high pitched buffeting, not mechanical noise from a broken fan).

The heat sink is a square tube, and I believe that it acts as a echo tube for the fan noise and amplifies it. I've tried reversing the fan and buying quieter 40mm fans. Reversing the fan helped slightly. Quieter fans didn't move as much air, and the unit got hotter than I was comfortable with. I bought a rubber gasket and rubber rings for mounting the fan. Not even sure that helped.

I've tried to hunt down a different heat sink, but couldn't find anything like it anywhere. I am pretty much at a loss of what I should try next.

Here are some pictures of the situation.









Thanks in advance!

Does it even need the tube?

Cut it off and mount a larger fan on top?

It hard to tell exactly what you need with that tube in place, but I would suggest you look for two or more smaller heatsinks that would do the job. A few PC chipset heatsinks attached with thermal tape may do the job. You may also want to see if you can put a slightly larger but slower fan in place. You might get a 60mm in there.

Cistron wrote:Does it even need the tube?

Cut it off and mount a larger fan on top?

Interesting consideration. What if I cut only the top side of the tube off with a dremel and blocked the small side vents so that all air must flow out the rear exhaust port? There would be considerable room inside the case where the fan wires are currently ziptied to the ribbon cable to cut a vent for an 80mm, 92mm or possibly even 120mm fan mounted inside the case pointed down.

Thoughts?

washu wrote:It hard to tell exactly what you need with that tube in place, but I would suggest you look for two or more smaller heatsinks that would do the job. A few PC chipset heatsinks attached with thermal tape may do the job. You may also want to see if you can put a slightly larger but slower fan in place. You might get a 60mm in there.

The tube has 4 points of contact to 4 evenly spaced audio output transistor chips (I believe they are output transistors, I could be wrong). There are three evenly spaced screws that go from underneath the board into the bottom of the heatsink. I considered getting a physically larger fan, but the inside of the case itself is only 53mm tall. I couldn't find a 50mm fan that had a considerably better noise/fan speed ratio.