Always consult the Owners Manuals first.
Note: the wiki is currently being updated with information about the FM3.

FX Loop block

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Axe-Fx XL Plus rear.png

Available on which products

  • Axe-Fx III and FM3: no
  • Axe-Fx II: 1 block
  • FX8: no
  • AX8: 1 block

Channels or X/Y switching

  • Axe-Fx II: no
  • AX8: no

What is the FX Loop block (FXL)

I/O 2 on the Axe-Fx II and AX8 can operate as an effects loop: FX Send (Output 2) and FX Return (Input 2). Alternatively, I/O 2 operates as auxiliary Input and Output ports.

The FX Loop block (FXL) enables the effects loop on the layout grid.

Possible uses of I/O 2:

  • Four Cable Method (4CM)
  • connect an additional instrument
  • insert an external device in the routing
  • duplicate or create independent output signals

Note: to make Output 2 act only as a duplicate of Output 1, the use of the FX Loop is not needed. Just enable ECHO OUTPUT 2 in the I/O menu.

On the Axe-Fx III and FM3, the Input block and Output block replace the FX Loop functionality.

Setting output levels

Signal to next block — LEVEL in the FX Loop block sets the level of there signal going to the block AFTER the FX Loop block. The Level value is stored per scene.

Signal to Output 2 port — use the OUT 2 knob on the front/top panel to set the outgoing signal level. Note: to enable unity gain on the AX8, you need to set the OUT knob on the hardware to its maximum position.

Nominal output level — the default nominal output level of the AX8 and Axe-Fx II is +4dB. This can be changed to -10 dB. Read this: I/O menu

Echo Output overrides FXL

The ECHO OUTPUT 2 parameter in the I/O menu lets you send a copy of the Output 1 signal through Output 2. The OUTPUT 2 MODE parameter determines whether this signal is stereo or mono.

IMPORTANT: if a preset contains the FX Loop block, ECHO OUTPUT 2 is ALWAYS ignored.

Special FX Loop scenarios

Signal with Cab Modeling to FOH, signal without Cab Modeling to backline

Use the FX Loop block to create two separate output signals:

  1. to FOH / studio monitors / headphones etc.: with cab modeling
  2. to backline (power amp and traditional cab): without cab modeling

Create a regular routing with the Cab block at the end. Insert the FX Loop block, either in series right before the Cab block, or on a separate row (connected to the block before the Cab block). Make sure that the FX Loop block is connected to the Output block. Connect OUT1 to the FOH / FRFR etc., and OUT2 to the power amp. Use the OUT 1/2 knobs on the top/front panel to control the output levels.

The Axe-Fx II and AX8 provide a factory preset specifically created for this task.

Route a signal from Input 2 to Output 2

The trick below does not work with the AX8, because it requires the Feedback Send and Return blocks.

You can connect an instrument, music player etc. to Input 2, use FXL to let its signal enter the grid, and then send the processed signal to Output 2:

  1. Connect the external gear to Input 2.
  2. Select the correct Input Mode for Input 2 in I/O > Audio.
  3. Add a Feedback Return block to a separate row. Set Mix and Level to 100, to start with.
  4. Add a FXL block after Feedback Return (and effect blocks if desired). Set Level at 100.
  5. Add a Feedback Send block after FXL, with Send at 100.
  6. Turn up Output Level on the front panel to get signal out.

The described routing lets the signal from Input 2 enter the grid through FXL, to be processed by the effect blocks after FXL. FXL's Level parameter sends signal to Feedback Send, which routes the signal back to Feedback Return. From there it enters FXL again, but this time to send the signal to Output 2.

If you want this routing to go to Output 1 as well, connect Feedback Send to the grid's output. WARNING: this will cause extremely loud and high-pitched feedback when nothing is connected to Input 2!

If you want to add signal from Input 1 to Output 2, connect that row to FXL.

Split FXL into a mono effects loop and an auxiliary output

The FX Loop block is stereo. By panning, you can have an external loop and still use it for an auxiliary output.

"Put the FX Loop block in front of the amp block and hard pan the signal going into the FX Loop block from that row hard left. In the amp block, set input select to left only. Put a feedback send block before your cab block. Put a feedback return block in another row before the FX loop block and set its balance to hard right. Connect the feedback return block output to the FX Loop block input. The rear Input 2 L and output 2 L jacks are then used for pre-effects and output 2 R is used to feed your power amp and cab on stage. The front panel output 2 knob will control both sides together, so you'll have to play with the levels in the FX loop and feedback blocks to get it all set right."

Or use FX Loop for two loops in series:

"It's possible to use the FX Loop as two mono loops in series, with a certain routing using feedback send/return." source

Add sound from the computer to the output

Set USB Digi SOURCE in the I/O menu to OUT 2. source

AX8: preventing a feedback loop

The Axe-Fx II has a sensor on Input 2. If nothing is connected, the effects loop will not run, which prevents feedback loops. source

The AX8 does not have this sensor. That's why you should ALWAYS put the FX Loop in a split (parallel) path, when using it to create a separate output signal.

Avoiding feeding signal to Output 1

If the FX Loop block is used to send a signal to Output 2, it probably should not feed Output 1 as well. In that case do not connect the FX Loop block to the grid output. If that can't be avoided, turn down FXL's LEVEL to -80. In the odd case that this does not suffice, set the BALANCE controls in the FX Loop block and output mixer oppositely.

Change FX Loop from stereo to split

How to change FX Loop from stereo to split