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Discussion Starter #1 (Edited)
Behringer iNuke NU1000 Amp Amplifier Fan Swap How-To w/ PICS & VID

It has been a while since I have posted here - my original EP4000 fan swap thread got stickied so I thought I would post a part 2 of the new iNuke series using a fresh out of the box NU1000 I received this week in the mail.

Upon being powered on the NU1000 had a definite fan noise while sitting on my kitchen table. I was hoping for an audible drop similar to what the EP4000 fan swap had improved on the original EP stock fans. The fan swap I made in the pair of EP4000s I am still using resulted in a very significant db drop yet never seemed to jeapordize the ability of the EP4000s to run cool (even while wired in 2 ohm stereo for extended durations).

The photos attached show the iNuke NU1000 on my kitchen table with the top being removed and the stock fan being swapped for an Adda Inc AD0812XX-D71 (Jameco part # 2095365......approx $8 ea).

Swapping the fan out on the iNuke amp was easier than the EP fans - 6 screws on top and then remove the 4 screws on the back of the amp holding the external fan guard.........then it is a simple matter of soldering on the new lead to the pigtail from the plug and the new fan bolts into place perfectly.

The bad news......the new Jameco fan IS quiter than the stock fan but it is NOT as significant of a drop as the improvement seen in the EP4000 fan swap. At best, I see the Jameco part as a temporary improvement.

If others have swapped their fans in the iNuke series and have had better results and more significant fan noise reductions please post your fan part # and vendor!

I have yet to test this amp, it will be powering a Dayton Reference Series RSS390HO-4 15" sealed sub. I will post my impressions of this amp in the next couple of weeks as the new system gets pieced together.
 

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I heard somewhere that using silicone mounts on the fan helps to reduce alot of the noise. maybe it is worth a shot if you have some?
 

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Discussion Starter #4
Silicone mounts may help but my opinion is that the main cause of the wind "noise" isn't so much the fan itself.....it is the sound of the air being vented by the black looking "cover" of sorts that has to be removed before the stock fan can be removed. The stock "shroud" seems to direct the flow of air from the fan in a downward manner and I think the rush of the air from the fan moving inside the shroud is the biggest noise culprit.

You can see in the last photo I posted a pic of the new fan installed without the shroud - when the amp was plugged in and tested this way it was very quiet even with the top off.....however when I then placed the black shroud back in place the noise returned and even with the amp cover back on the fan noise was worse than with the amp opened up being tested with NO shroud in place.

Perhaps the best solution is to ditch the shroud - my only concern would be overheating and diminished protection for the internal amp parts that may need it the most.

My amp will be sitting inside of a rather snug stereo stand and I think this may help mask some of the "wind noise" that I can currently hear with the NU1000 while I test it out on my kitchen table.
 

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Discussion Starter #6
Could you just open of the shroud a bit by cutting the inlet back some ?

Good question - here is the answer - follow the YouTube link below - today I shot a quick HD video of how to replace the fan in the iNuke amps and just posted it to YouTube......in the video I actually took your suggestion and removed the stock fan shroud and "trimmed it" to size. The end result is a somewhat improved fan situation - compared to the aftermarket fan/stock fan shroud, the new combo of aftermarket fan/modified fan shroud is an improvement.

Ultimately ditching the fan shroud would basically reduce fan noise levels to nearly inaudible......or making this simple mod to the fan shroud will get you one step closer to having a quieter fan. Check out the video for a look inside the NU1000.

 

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Discussion Starter #10
If you really want to drop the noise level, I recommend this fan:

http://www.vantecusa.com/front/product/view_detail/113

Thanks - may give it a try. I have lived with the current inuke/aftermarket fan combo for a while now and I definitely want to take the fan noise down another notch or two.

I am quite impressed with the amp - the 1000w rating may be a meaningless "max output" but this iNuke1000 bridged to 4 ohm mono driving a 15" small sealed sub is quite powerful.

For $200 I would choose this over comparably priced subwoofer "plate amps" any day of the week.
 

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Tried this mod on my 3000. The standard fan is actually pretty quiet with the lid off. Once the lid goes on its intolerable....and this is with the amp cool. Once it warms up, the fan sounds like a wind tunnel!

My solution was to fit a 120R 2w resistor in series with the original fan. The fan is totally off until the amp warms up (5mins) & is now tolerable fully ramped.

On the 3000, there are flat heat sinks which will take adhesive fin heat dissipators.
 

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I replaced the very noisy original fan with a Nexus Basic 80mm, cant hear a whisper from this as they claim " worlds quitest fan"!

The funny thing is that the Nexus fan looks exactly as the Behringer fan, same shape on chassie and fan blades.

regards, Jonas
 

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Cant figure this out.......

The original fan itself is not that noisy with the top cover off. Once the cover is on, there is a resonance coming from the air as it is pulled thru the vents. The only way to quieten the fan is to reduce the air flow, which is what the resistor does.

Are you saying the Nexus fan achieves the same thing by spinning more slowly?

Also, the noise varies as the fan ramps up. With the resistor, the fan is actually off when you switch on & starts to spin as it warms up.
 

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Maybe I've got hold of a particular noisy iNuke, as I can't enjoy the music with the amp located in the same room..I think that the Behringer fan has very cheap bearings, and that this bearing noise is
spreading to the fan shroud and top cover. The Nexus fan typically also rotates at lower speed, which in conjugate with superior bearings almost totally kills fan noise.
 

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Yes, connect black to black and red to red. Carefully cut away the yellow cable as close as possible to the fan motor. Keep in mind that I, due to neighbors, haven't run the iNuke at full level for any longer timespan with the Nexus fan, but this far there has been no problems, just very cool air emerging from the backside. I will not take responsibility for damages that can arise due to this modification!
 

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I will not take responsibility for damages that can arise due to this modification!

Of course :nono:

Will let you know how fan compares to my resistor mod..........
 

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hey guys :)

the inuke and special the dsp version is really intrested.
but the fan is not to accept in home cinema :(

a slower/silent version is critical under max load. (some people write on thomann.de and parts-express.com the amp was still quiet the job :( )

so i thin to a new "really" mod.

can we discuss if its really possible what i like to do? :)
1. using equal zalmann ZM-NBF47 (pc northbridge colling heat sink) on top of the mosfet
2. if it thermal perfectly we can change the heat pad under the heat sink with thermal adhesive grease (arctic silver)
3. change the fan to a silent 12-16db one

what do you think about it?

(and sorry for the bad english :))
 

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Agree....fan noise not acceptable in home environment.

Must point out this mod relates to my NU3000DSP

Problem I found is you cannot tell how loud fan is going to be until unit warms up & is giving maximum voltage to fan. My solution was to try several resistors & eventually settle on 120R.

Fan showing resistor:


You can use stock fan which does not spin until unit warms up, & then the speed is kept to an acceptable noise level.
I have also found blowing the air using the fan at the rear creates turbulence noise as the air passes through the front louvres.
So far, the quietest solution I have found is mounting the fan on top. altho the original fan with resistor is acceptable compromise. I had a piece of perspex lying around which I cut for this purpose. I have positioned the fan directly on top of the heat sensitive components:



and eliminated cowling of favour of adhesive heat sinks mounted to all the transistors.




Heatsink here:
http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=1773319

In this way the air is draw through the top of the unit & expelled from the front & back which is much quieter. I have used a fan I had lying around for this experiment & the stock fan is left in position but not used.
 

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Maybe I've got hold of a particular noisy iNuke, as I can't enjoy the music with the amp located in the same room..I think that the Behringer fan has very cheap bearings, and that this bearing noise is
spreading to the fan shroud and top cover. The Nexus fan typically also rotates at lower speed, which in conjugate with superior bearings almost totally kills fan noise.
Did this fan mod. It is certainly much quieter than the stock fan as the fan is lower power, so acceptable in home environment. The fan in the top cover is quieter still, but alot more work.
 
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