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So as I understand it the issue of using an 80mm to 120mm fan adapter on the back of the amp is that the 120mm fan extends down below the amp's feet. There are actually several different offset and angled (45°, 90°, etc.) 80mm to 120mm adapters available that would solve that issue and a single 120mm fan feeding through the original 80mm fan opening seems to be the most elegant solution. The offset one in the first two images below is the one I'd probably go with:




 

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Discussion Starter #22
So as I understand it the issue of using an 80mm to 120mm fan adapter on the back of the amp is that the 120mm fan extends down below the amp's feet. There are actually several different offset and angled (45°, 90°, etc.) 80mm to 120mm adapters available that would solve that issue and a single 120mm fan feeding through the original 80mm fan opening seems to be the most elegant solution. The offset one in the first two images below is the one I'd probably go with:




That is a nice solution too if you have space above and/or below. Where can those be acquired?
 

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That is a nice solution too if you have space above and/or below. Where can those be acquired?
I just did a Google search for 80mm to 120mm fan adapter and went to Images. I think all the images I linked to were from eBay. For example, the offset one sells on eBay for $17.24 plus $5 economy shipping from a seller called elegantmarketing.
 

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The new nx lines fans are not even loud.... Is this even needed?
 

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The new nx lines fans are not even loud.... Is this even needed?
My NX6000D is pretty loud. You can definitely hear it from 15 feet away. Even at its quietest (I measured about 5V) at start up it’s still audible from 15 feet away.
 

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My NX6000D is pretty loud. You can definitely hear it from 15 feet away. Even at its quietest (I measured about 5V) at start up it’s still audible from 15 feet away.

I've got a 3000d and it's not loud at all. I mean, I can hear my projector fan from 15 feet but it's not loud. Of all the pro amps with fans I've ever heard, the nx line is by far the quietest.
If that's still too loud, then I guess have at it.
 

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My NX6000D is pretty loud. You can definitely hear it from 15 feet away. Even at its quietest (I measured about 5V) at start up it’️s still audible from 15 feet away.

I've got a 3000d and it's not loud at all. I mean, I can hear my projector fan from 15 feet but it's not loud. Of all the pro amps with fans I've ever heard, the nx line is by far the quietest.
If that's still too loud, then I guess have at it.
Well this is my first pro amp that I’ve used in a home setting so I guess I have no other reference to compare. The spec sheet on the fan used in the NX6000d says it is rated at 40dB which is hardly quiet at all (though it produces a ton of static pressure and airflow). If that’s quiet enough for you then great but that is definitely distracting for me (I don’t use a projector either). I’m big on dynamics in sound (quiet should be quiet and loud should be loud) but I understand some people may just like loud.
 

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Well this is my first pro amp that I’ve used in a home setting so I guess I have no other reference to compare. The spec sheet on the fan used in the NX6000d says it is rated at 40dB which is hardly quiet at all (though it produces a ton of static pressure and airflow). If that’s quiet enough for you then great but that is definitely distracting for me (I don’t use a projector either). I’m big on dynamics in sound (quiet should be quiet and loud should be loud) but I understand some people may just like loud.
The inuke series as a whole seems to have gone through a couple fans, to add to the confusion. Some later model inukes report not having noise, others do. That being said, my 6000dsp is pretty loud, but I haven't bothered swapping the fan yet. I probably will, however. My projector fan is pretty quiet in comparison, even when it's right above my head and the inuke is about 10' from me.
 

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Consider that dB is not the whole story on noise annoyance. Pitch also plays a big role with higher pitched fans generally more annoying to more people than lower pitched fans. It's the lower pitch along with the lower dB of a slower turning 120mm fan that makes it more acceptable to more people. That and the simplicity of an external mount with no drilling or cutting required are what makes the offset 80mm to 120mm fan adapter so appealing to me. Of course I don't have one of the Behringer amps yet so this is all just future planning for me. :)
 

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Discussion Starter #32
Well this is my first pro amp that I’ve used in a home setting so I guess I have no other reference to compare. The spec sheet on the fan used in the NX6000d says it is rated at 40dB which is hardly quiet at all (though it produces a ton of static pressure and airflow). If that’s quiet enough for you then great but that is definitely distracting for me (I don’t use a projector either). I’m big on dynamics in sound (quiet should be quiet and loud should be loud) but I understand some people may just like loud.
The stock fan is a Jameco JF0825B1URTR. Closest I could find is JF0825B1UR-R. 52 CFM @ 4000 rpm and 40dB. Yikes! I see nothing about static pressure ratings. These draw 370 mA. It takes a lot to spin at 4000 rpm.

https://www.jameco.com/z/JF0825B1UR-R-Jamicon-Corporation-Fan-12VDC-52-CFM-80X80X25-52-CFM-Dual-Ball-Bearings-12-Leads-UL-CUL-TUV_2081078.html

From the Noctua website: 17.1db and 64.6 m3/h (38 cfm) @ 1600 rpm, 11.6dB and 51.1 m3/h (30 cfm) @ 1250 rpm with L.N.A. resistor and 8.4dB and 42.9 m3/h (25 cfm) @ 1050 rpm with U.L.N.A. resistor. Not too bad. Static pressure is 1.62, 1.04 and 0.71 mm H2O. These fans draw 0.07A max so two of these draw half of what the stock fan draws.

https://noctua.at/en/nf-a9-flx/specification

I wouldn't run the fans at full speed. I like Noctua for their renown quality and longevity and will run them with the U.L.N.A. resistor. You can put whatever fans you want on there. There are lots of other good brands, pick one you like.

At my work, we design systems with pumps. We like to oversize the pumps and run them slower. It takes less power and the pumps last gignificantly longer.
 

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I run the Noctua Redux fans in my Beheringers, they have worked great so far.

The only issue is with their wiring gauge, its too big to fit in the 2pin, snap connector so I had to splice them.
 

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Well this is my first pro amp that I’ve used in a home setting so I guess I have no other reference to compare. The spec sheet on the fan used in the NX6000d says it is rated at 40dB which is hardly quiet at all (though it produces a ton of static pressure and airflow). If that’s quiet enough for you then great but that is definitely distracting for me (I don’t use a projector either). I’m big on dynamics in sound (quiet should be quiet and loud should be loud) but I understand some people may just like loud.
Ahhh, well that explains it. The crowns are decent quiet but if you get into the bigger power ones, they are wayyyyy louder than the nx line. They are considered about the quietest pro amp you can get (that has a fan)
 

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At my work, we design systems with pumps. We like to oversize the pumps and run them slower. It takes less power and the pumps last gignificantly longer.
Not to derail this thread but why would oversizing pumps (or anything) and running them slower save power? Pump power is a function of head, flow, pump efficiency and motor efficiency. Using a larger pump and slowing it down doesn’t change any of those unless you picked a smaller pump with the incorrect efficiency at operating conditions (closed loop system).
 

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Assuming the pumps are designed for the same life, the oversize pump is running at less than its rated capacity, so lower stress levels.


Not to derail this thread but why would oversizing pumps (or anything) and running them slower save power? Pump power is a function of head, flow, pump efficiency and motor efficiency. Using a larger pump and slowing it down doesn’t change any of those unless you picked a smaller pump with the incorrect efficiency at operating conditions (closed loop system).
 

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Assuming the pumps are designed for the same life, the oversize pump is running at less than its rated capacity, so lower stress levels.
I was just commenting about the part of how it would use less power. According to every applicable engineering equation it wouldn’t. Less wear and tear by operating at a lower speed makes sense but not the power part.
 

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I was just commenting about the part of how it would use less power. According to every applicable engineering equation it wouldn’t. Less wear and tear by operating at a lower speed makes sense but not the power part.

While you are right, the larger pump would use less voltage to achieve the same vacuum power with a bigger piston. It’s not just motor size, think about woofer size, the bigger the woofer the less power is needed at lower frequencies.

Also less heat and less resistance, bigger bearings having less restriction. It all adds up but I imagine the biggest effect comes from lasting longer and needing less maintenance.


Sent from my iPhone using Tapatalk
 

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I was just commenting about the part of how it would use less power. According to every applicable engineering equation it wouldn’t.

Oops, read too fast, missed that.

It is possible that power consumption is less.

Fans have a lot of slip, and viscous fluid friction increases with the square of velocity.

The net result will depend on the integrated blade velocity profile with radius.

I'm too lazy to think it through but my guess is that for the same tip velocity, a number of smaller fans with the same flow area as a larger fan will produce less total flow, and that when the flow is equalized by increasing rpm, they will have more viscous losses.

Oops, still reading too fast, just noticed your second sentence.

Which equations are you referring to?
 

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Oops, read too fast, missed that.

It is possible that power consumption is less.

Fans have a lot of slip, and viscous fluid friction increases with the square of velocity.

The net result will depend on the integrated blade velocity profile with radius.

I'm too lazy to think it through but my guess is that for the same tip velocity, a number of smaller fans with the same flow area as a larger fan will produce less total flow, and that when the flow is equalized by increasing rpm, they will have more viscous losses.

Oops, still reading too fast, just noticed your second sentence.

Which equations are you referring to?
Standard hydraulic power equations. The link below is for pumps but it’s basically the same for fans.

https://www.google.com/amp/s/www.engineeringtoolbox.com/amp/pumps-power-d_505.html
 
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