KHE + Fractal AxeFx III in 4-Cable-Method


This guide explains how to use the Fractal AxeFx III as a multi-effects unit with the KHE amp switcher in a 4-Cable-Method (4CM). This enables to:

  • Use the AxeFx’s Pedals (Boost, Overdrive, Gate and such) in front of the amps (like normal pedals).

  • Use the AxeFx’s Effects (Delay, Reverb and such) in the fx-loop of the tube amplifiers (post-preamp).

  • Remotely control the KHE by MIDI with the AxeFX Footswitch.

  • Use the KHE’s Master-FX-Loop Bypass Switching to remove the effects-chain from the fx-loop.

In this setup, the AxeFx functions as a mono multi-effect unit. Only the stompbox- and effect blocks are active. All amp- and speaker-modelling blocks are disabled. A Mono Loop Block is inserted to create the insert point for the amp fx-loops.

In combination with the FX-Loop Switching function of the ACS 4x4FX (or ACS 8x4 / ASX 8 with the AFX 8), it enables to use the AxeFx as a multi-effect unit in 4-CM with all connected amps.

Connections & Setup

 
 

  1. Connect the Guitar to the AxeFx’s guitar input INPUT 1.

  2. Connect the AxeFx’s OUTPUT 3L to the KHE GUITAR INPUT jack. This sends the guitar signal after stompbox section to the guitar input of the amp switcher.

  3. Connect the AxeFx’s INPUT 4L to the KHE FX INPUT jack. This connects the master-fx-send of the amps/KHE to the input to the AxeFx’s effect section (post-distortion).

  4. Connect the AxeFx’s OUTPUT 4L to the KHE FX OUTPUT jack. This sends the signal after the AxeFx’s effect section back the master-fx-return of the KHE and back to the power amp of the activated amplifier.

Check the AxeFx III’s User Manual Section 4 “Setting Up” => “Four-Cable Method” for all details on how to setup the preset and routing. IN1 / OUT3 are assigned to the pre-effects section, and IN4 / OUT 4 are assigned to the post-effects section. Use shielded instrument cables (TS) for all AxeFx connections (or Humbuster Cables for OUT3/4). Make sure to deactivate all amp- & cab-models on the preset.

On the KHE, press the small FX Button to activate the fx-loop. The FX light turns fully on. If the FX light is dark or dimmed, the entire effects chain is true-bypassed. The on/off state of the master-fx-loop is individually saved for each amp and gets recalled automatically when switching amps.

Make sure the amp fx-loops are all set to serial or parallel with 100% mix setting. In case an amp has a bad fx-loop design that still passes some dry signal, it will be mixed with the AxeFx signal which causes a bad phasing or chorusing sound due to the latency of the AD/DA conversion.

Notes

  • A few KHE users reported a hum- or ground-loop issue with this type of setup. For most users it seems to work fine without any problems, but in some cases, there may be a ground loop problem. To solve the issue:

    • Try experimenting with the AxeFx’s and KHE’s Ground Lift switches.

    • If using Humbuster cables, try using normal instrument cables instead. If you use normal instrument cables for OUT 3L and OUT 4L, try Humbuster cables if you already have them (as mentioned in the AxeFX Manual).

    • As a last resort, insert a high-quality signal isolation box (with transformer) between the AxeFX OUT 3L and the KHE Guitar Input to remove the ground loop. (add link little helpers).

To build this 4-CM amp switching setup, you need a KHE amp switcher with the Master-FX-Loop Switching feature. For up to four amplifiers, check the KHE ACS 4x4FX which has the fx-loop switching feature built-in. For the KHE ACS 8x4 or ASX 8, the fx-loop switching can be added by the KHE AFX 8 extension unit. All KHE units can be fully linked and daisy-chained to expand the switching channels.

Links:

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