Pedals & FX, Setup & Signal Chain

How to Set Up the NUX MG-400 With Your Amp (FX Loop)

Written By :Andrew Siemon

NUX gave me the MG-400 and the Trident to test out so I figured I would make some tutorials on how to use them as well. The process isn’t much different from the Trident which I showed earlier.

Michael from NUX Audio's Message (Trident MG-400)
The message that I got from the marketing specialist over at NUX Audio.

To set up the NUX MG-400 with your amplifier, run a cable from the Return of your amplifier’s FX Loop into Output (R) of the MG-400. Connect your guitar to the MG-400’s Input and then power the MG-400 with the included 9VDC power supply. Turn down the MG-400’s master volume before turning it on.

How to Connect the NUX MG-400 To Your Amplifier (FX Loop)

How to Set Up the NUX MG-400 Setup In Your Amp - Infographic
Run a cable from the FX Loop’s Return to the Output (R) of the pedal, and then another cable from the Input to the guitar. This is the long and short of setting up the MG-400 with your amplifier.

This will effectively bypass the pre-amplifier of your guitar amplifier, rendering its EQ and volume controls useless.

Once you’ve set it up in this way, you can crank up the volume to 10 if you wanted and it won’t do anything (I strongly suggest NOT doing this though).

The result of that is that the primary volume controls will be with your MG-400 going forward, and not the volume on your amp. This is why the volume is the 1st step:

1) Turn Down the Master Volume On the MG-400

1) Turn Down the Master Volume On the MG-400
The knob for the MG-400’s master volume.

This is a good move because you don’t want the MG-400 to be incredibly loud when you first start using it.

Like with the Trident, I found the MG-400 to be too loud by default. Obviously, not that big of a deal, but it’s something to know about before using it.

The same problem exists with the drum kits on the BOSS RC-5.

2) Run A Cable From the Amp’s Return (FX Loop) to the Output (R)

2) i) Run A Cable from the Amp's Return to the Trident's Output - 1
The Send/Return ports of the FX Loop are on the backside of the Orange 35RT.
2) ii) Run A Cable From the Amp's Return (FX Loop) to the Output
I tried the L/Mono port but it didn’t work.

It isn’t clear to me why the Mono port didn’t work, because the Mono ports are usually what work when you use a BOSS pedal, or any other for that matter.

It’s possible I had something set up wrong, or maybe the L/Mono port is supposed to do something different in this case.

3) Connect A Cable from the Input of the Pedal to the Guitar

3) Connect A Cable from the Input of the Pedal to the Guitar
The Input jack of the NUX MG-400.

Once you’re at this stage, you’re almost done.

4) Connect the 9VDC Power Supply to Your MG-400

4) Connect the 9VDC Power Supply to Your MG-400
Power the MG-400 with the included power adapter or a compatible power supply like the Voodoo Labs Pedal Power 3+ (on my page).

The MG-400 has a current draw of 280mA approximately, according to the Easy Music Centre.

5) Turn On the MG-400 First & Then Your Amp

5) Turn On the MG-400 First & Then Your Amp
The Power switch on the MG-400.
5) Power on the Amp - 1
Then you can power on the amp.

This is how you avoid that annoying popping sound whenever turn on all of your pedals with the amplifier turned on.

I find it’s especially loud when you’re using the Return/FX Loop method for connecting modellers like the Trident and the MG-400.

I’ve talked about this before in my guide on how I’ve optimized my setup with a one-click power-up.

6) Dial In Your Preferred Master & LEVEL Volume

6) Dial In Your Preferred Master & LEVEL Volume (Master & Volume)
From here, you can start dialling in the appropriate master volume.

I would go ahead and set your master volume fairly low to start. After, go through the various presets and find out the average volume.

The volume levels may vary between presets, with clean tones often being quieter than overdriven or high-gain settings. Adjust the master volume accordingly.

I found myself repeatedly reaching down and turning down the master volume whenever I would switch to a high-gain preset. This annoyed me a bit, but it’s not a huge deal.

1 Tip for Setting Up the MG-400

Rock the Expression Pedal Forward to Increase the Volume

I found that I also had to move the expression pedal up and down at least one time for the pedal to begin making sound through the amp.

MG-400 When the Pedal is Quiet - Rocked Backwards
The NUX MG-400 with the pedal rocked all the way backwards.

When you haven’t decided what effect for it to control, the MG-400’s expression pedal acts as a volume pedal by default, which is really cool.

You can set it up it to control other effects. For example, when you engage it by clicking the “Pedal” button on the MG-400, it’ll activate Wah-Wah within some presets.

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Andrew Siemon is the principal creator for, a website entirely devoted to all things guitar. From repairs, music theory, chords, and improvisation, to recording at home. I've been doing this for 20 years and I've got another 50 in me.

2 thoughts on “How to Set Up the NUX MG-400 With Your Amp (FX Loop)”

  1. Instead of connecting to Amp (FX Loop), I would like to connect the MG-400 directly to my Behringer UMC1820 Audio Interface to practice and Record tracks. Note that the Studio monitor speaker is connected to Main out of the audio interface. Will it work??
    Signal chain: Guiter -> MG-400 -> Behringer audio interface -> PC/Laptop (DAW).


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