Always consult the Owners Manuals first

FX Loop block

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Axe-Fx XL Plus rear.png

Available on which Fractal Audio products

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

X/Y and channels

  • Axe-Fx III: n/a
  • Axe-Fx II: no
  • FX8: n/a
  • AX8: no

What is the FX Loop

The Axe-Fx II and AX8 provide an effects loop, aka FX Send/Output 2 and FX Return/Input 2. These jacks also function as a separate Input resp. Output port. The FX Loop block (FXL) enables the loop.

Possible uses include:

  • Setting up the unit for 4CM.
  • Connect a 2nd instrument to Input 2.
  • Insert an external device in the routing.
  • Duplicate or independent output signals.

Note: to make Output 2 act only as a duplicate of Output 1, FXL is not needed. Just set ECHO OUTPUT 2 to Output 1 in I/O.

Setting levels

To set levels, you need to look at the FXL block settngs as well as the OUT2 knob on the front/top panel.

The Level parameter in the FXL block affects the signal flow to the block AFTER the FXL block, not the signal to OUT 2.

On the AX8 set the output knob on the hardware to its maximum position to enable unity gain.

The Level value is stored per scene.

Be aware that the Input 2 and Output 2 levels on the Axe-Fx II are fixed at +4dB. These settings are adjustable on the AX8.

Sending a signal with cab modeling to FOH and a signal without cab modeling to power amp and traditional cab

Use the FXL block to send two different output signals:

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

Create a regular routing with the Cab block at the end. Insert the FXL 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 FXL block is connected to thge 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.

Routing a signal from Input 2 to Output 2

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

Double duty: effects loop AND auxiliary output

The FXL block is stereo, so by panning you can have an external loop and still use the FXL's auxiliary output.

(Mr Fender): "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."
(Bakerman) "It's possible to use the FX Loop as two mono loops in series, with a certain routing using feedback send/return."

Using the computer as input source

Set I/O > USB Digi Source to: OUT 2. source


FXL versus Echo Output parameter

ECHO OUTPUT 2 in the I/O menu lets you copy the signal from Output 1 and send it through Output 2. OUTPUT 2 MODE determines whether it's a stereo or mono signal.

But when a preset contains the FXL block, the parameter ECHO OUTPUT 2 is ALWAYS ignored.

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 FXL in a branched off (parallel) path, if you use it for a separate output signal.

Avoiding feeding signal to Output 1

When FXL is used to send a signal to Output 2, it probably should not feed Output 1 as well. In that case do not connect FXL to the grid output. If connecting FXL to the output block cannot be avoided, turn down FXL's level to -80. In the odd case that this does not suffice, set the FXL's and output mixer row's Balance controls oppositely.

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