Quieter Behringer NX6000D Amp: Fan Replacement Guide

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Intro

Just like my Yamaha PX series amp, the Behringer NX6000D amp was quite loud out of the box. It appears that the same modifications will have to be done on this amplifier to ensure it operates more quietly in my home theater. In this guide, I’ll walk through the necessary steps to change the Behringer NX6000D chassis fans to quieter ones, if you would like to do the same.

Why Noisy Fans?

Since this is the second PA amp I am using in my home theater, it raises the question: why do so many of these PA amps have fans on the louder side?

Wouldn’t you want silent fans, no matter the use? It would bring less noise pollution, after all, and I am sure we would all appreciate that.

The reason is fairly simple: when designing and producing these amps, there are always trade-offs to consider. One key trade-off is between cooling efficiency and noise levels. High-powered amps generate a lot of heat, and manufacturers often prioritize cooling performance to ensure reliability and longevity over quieter operation. This is especially true for professional audio equipment, which is typically used in environments where the amps are far from the sound field and often outside. Therefore, they can be as loud as needed since no one will hear them during operation.

So, if louder fans equal better cooling performance, wouldn’t it be unfavorable to replace them with quieter ones? Not necessarily. Designing efficient and quiet fans takes extra design considerations and tends to cost more. Manufacturers tend to focus on cooling performance over noise reduction in order to keep costs down and meet the reliability needs of professional audio equipment. This cost is usually too great for the market and scale that these amps are designed for, but for those who are only buying a couple of fans, the cost is manageable.

For home theater enthusiasts like us, we strive to have the quietest room possible so that the only noise we hear is from what we are actively listening to rather than background noise. This greatly improves the clarity and dynamic range we can experience in our home theaters. Plus, we are not usually running these amps as hard, as long, or in as harsh environments as professional audio equipment. With a bit of modification, we can achieve both effective cooling and quiet operation.

Fan Choice

Since both the Yamaha PX series and the Behringer NX series amps use the same fan size, the same fan can be used for both modifications.

The Noctua NF-R8 redux-1800 High Performance Cooling Fans are super quiet at 17dB and have close to the same airflow as the existing fan. The original fan’s airflow is 46 CFM while the new fan is a little bit lower at 31 CFM. This should be close enough to not cause concern as we are not using the amp in as harsh environments as the amp is rated for. The main benefit of the Noctua fan is that it is over 20 dB quieter, which means that it is subjectively 25% as loud as the stock fans.

Replacing the Fans

Procedure:

Step 1: Disassembly

1. Make sure the device is unplugged.
2. Remove the top cover (6 screws).

Step 2: Remove Fans

1. Unplug fan wires (there may be hot glue holding the fans in, just gently pry it off with a small screwdriver).
2. Using a #2 Phillips head screwdriver, unscrew the fans from the outside (4 screws per fan).
3. Remove fans from the case.

Step 3: Mount New Fans

1. Screw in the Noctua fans using the screws from the original fan.
   • Note that you can either orient the fans as exhaust or intake. I positioned them as exhaust fans, so they blow out Screw in the Noctua fans using the screws from the original fan.
     Note that you can either orient the fans as exhaust or intake. I positioned them as exhaust fans, so they blow out through the back of my case. This setup is better for the airflow of my equipment rack. To learn more about how to effectively cool your equipment rack, check out How to Keep Your AV Equipment Cool: Passive and Active Cooling Methods.

Step 4: Remove Board Connectors

To connect the Noctua fans to the amp’s board, we need to first remove the existing plastic fan connectors from the board.

1. Carefully, with your hand, pull up on the plastic connector until it lifts off the two leads. It will require some strength to get them to start moving. You can use a small flat head screwdriver to pry up on the connector if necessary.
   • Note: Be very gentle and careful, as it is possible to break the leads or damage the board if you are not cautious.
2. Repeat this process for the second connector.

The picture below shows how it should look with one connector removed:

Step 5: Wiring the Fans

1. Route the new fan wires as show in the picture

Option 1: Without Fan modification ( Easy Method)

1. Plug in Noctua connectors as shown in the second picture. Note that the leads coming out of the board are labeled as well: black wire to (-) and red wire to (+).
   • Note that in both cases, the yellow wire is not going to be connected to anything. This is okay, the yellow wire is only used as speed control. The fans will work just fine with only power.

This is the easier method but may not be the most reliable way of wiring due to the stock connector on the Noctua fan being slightly oversized for the leads coming off the Behringer board. The Noctua fan connector is fairly loose on the leads coming out of the board. This shouldn’t be a problem if you are not planning to move the amp around a lot or turn it over, but it was a little too loose for my liking. That is why I spent a little more time to complete method 2.

Option 2: With Fan modification ( More Difficult Method)

To address the loose lead issue, we are going to remove the Noctua connector and solder on a new connector that will be tighter on the leads for more security. The easiest way to accomplish this is to remove the connector from the end of the Noctua fan, then solder the JST extender cables to the wires of the Noctua fan.

1. Remove connector from the end of the Noctua Fan.
2. Cut back black wire on the JST cable extension (it is not needed as the PX series only runs off 2 wires).
3. Solder the Noctua Fan to the JST cable extensions.
   • Red Noctua → Red JST
   • Black Noctua → Black JST
   • Yellow Noctua → Not connected
4. Plug in JST connectors as shown in the second picture. Note that the leads coming out of the board are labeled as well: black wire to (-) and red wire to (+).
   • Note that in both cases the yellow wire is not going to be connected to anything. This is okay, the yellow wire is only used as speed control. The fans will work just fine with only power..

Step 6: Finishing Up

Once fans wires are installed and tied back. Reinstall the top cover.

Before installing the unit back into the rack, power it on and ensure that the fans turn on. They should activate about 10 seconds after powering on.

After ensuring that the fans do in fact work, everything should be good to go to enjoy quiet operation.

Results

Just like my experience modifying the Yamaha amp, this one yielded the same results. I could no longer hear the chassis fans outside my rack. In fact, with both amps running, the cooling fans on my AVR are louder than both of these amps combined.

This is an inexpensive way to silence this amp, and since Behringer uses the same chassis for the entire NX line, I bet you can apply this modification to all NX models.

Thank you for reading. If you are into DIY home theater, do not forget to check out our Display and Audio Calibration Guides or Speaker Building Guides to elevate your home theater to the next level.