Always consult the Owners Manuals first

Drive block

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Drive block.PNG

Available on which Fractal Audio products

  • Axe-Fx III: 4x.
  • Axe-Fx II: 2x.
  • AX8: 2x.
  • FX8: 2x.

X/Y and channels

  • Axe-Fx III: 4 channels.
  • Axe-Fx II: yes.
  • AX8: yes.
  • FX8: yes.

Yek's Guide to the Fractal Audio Drive models

Forum member Yek has written a comprehensive guide (PDF) that covers all drive models, including demo presets.

This wiki page provides links to the guide and presets.

Yeks Drives Guide.png

Drive blocks in the Axe-Fx III

The number of Drive blocks has been increased to 4 in the Axe-Fx III. With each Drive block containing 4 channels, that’s 16 (!) drives per preset.

Also, some of the Drives have been integrated into the Amp block as clean boosts (“Drive on 0, adjust Level as desired") with adjustable level: Neutral, T808, T808 Mod, Super OD, Full OD, AC Boost and Shimmer.

"The drive block in the III uses a higher oversampling ratio and double-precision filters in some places compared to the II." source

How the virtual controls compare to the real pedals

  • If the original pedal has a single Tone knob, use the Tone control in the model for authentic results.
  • If the original pedal has active EQ controls (Bass / Mid / Treble), use the Bass/Middle/Treble controls in the model for authentic results.
  • If the original pedal has a Volume or Level knob, it is mapped to the Level control.
  • If the original pedal has a Drive or Gain knob, it is mapped to the Drive control.
"The Tone control works the same as the modeled pedal. The Bass, Mid and Treble controls are a generic EQ that can be used in addition to the Tone control to further shape the sound." source

CPU usage

If CPU usage is an issue, select the right Drive type. Some types use more CPU than other types. There's a list in Yek's Guide to the Fractal Audio Drive models (PDF).

CPU usage is amplitude dependent on the Axe-Fx II, AX8 and FX8. CPU usage will change when you hit the strings when the preset has a Drive block (bypassed or engaged). This does not apply to the Axe-Fx III.

Tips and tricks

Fuzz, buffers and impedance

"The Fuzz in the Axe-Fx reacts as though there is a buffer in front of it (because there is). It's a limitation inherent to all modeling products. I modeled it using a nominal source resistance. I forget what I used for the source resistance but it was probably around 100K ohms. To really simulate it you would need a controller to simulate the changing output impedance of the guitar." source
"You can simulate the effect of a guitar into a Fuzz-Face using the Input-Z feature." source

Forum member AustinBuddy recommends 90k for Input Impedance with presets which have a fuzz as the first block. Not applicable to the AX8, because the AX8 has a fixed input impedance.

Models based on Tube Screamer circuit

Models based on the Tube Screamer circuit include: (source)

  • T808
  • T808 Mod
  • Super OD
  • Full OD
  • BB Pre
  • Eternal Love
  • Zen Master
  • LED Drive

This list should probably include FAS Boost too.

Tighten the tone with a Drive block or Boost Type

A Drive block before the Amp block, with minimal Gain, will tighten the low end of dirty amp tones. It allows turning down gain in the Amp block. This works well in particular with Tube Screamer-based Drive types.

Alternatively, use a "blocking" PEQ, copying High Cut and Low Cut values from a favorite Drive type. This will apply the same coloring as the drive, without the gain and CPU usage.

The Axe-Fx III also provides Boost Types: integrated Drives replicating the oft-used clean boost technique (“Drive on 0, adjust Level as desired"). Boost Types are: Neutral, T808, T808 Mod, Super OD, Full OD, AC Boost and Shimmer. The Boost Level controls the amount of boost.

Turning an Amp block into a Drive

Insert a second Amp block before the main Amp block, set its Supply SAG to zero ("p.a. off") to switch off power simulation, and you have a virtual preamp pedal. Set the main Amp block to a fairly clean tone for best results. Try with these models: Euro Blue/Red/Uber, Friedman, Dizzy, 5153.

More information:

Using the Pitch Detector to add gain to single notes

Attach Pitch (internal controller) to the Drive parameter and use Slope in the modifier menu to fine-tune. This adds gain to single notes when played high on the neck. Source

Drive block parameters

The parameters are also explained in the Owner's Manual.

Parameters table

Parameter Axe-Fx III Axe-Fx II AX8, FX8
Type yes
Basic - Drive yes
Basic - Tone yes
Basic - Mix yes
Basic - Level yes
Basic - Low Cut, Hit Cut yes
Basic - Bass, Mid, Treble yes
Expert - Clip Type yes
Expert - Clip Hardness yes
Expert - Bias yes
Expert - Slew Limit yes
Expert - Mid Frequency yes
Expert - Bit Reduce yes
Expert - Sample Rate yes
Input Select yes


Unlike other effect blocks, Mix at 0% in a Drive block is not equivalent to 100% dry signal ("True Bypass").

"The models let clean through even with the mix at 100%. It depends on the diodes though as to how much clean is mixed. Our models are based on the most common versions." source
"The mix control in the Drive block controls the ratio of clean to dirty in the distortion stage. It's not the same as the standard mix control in the other effects." source

The Mix control operates prior to any tone control. This lets you mix some dry in with the distorted signal but still maintain overall tone control.

Some players like to turn down the effects’s Mix level (80% or lower) to increase transparancy and decrease buzziness.

Sample Rate Deduction

Use Sample Rate Reduction to intentionally allow aliasing, for creative effects.

Bit Reduction

Use Bit Reduction to intentionally lower the resolution of the signal, for creative effects.

Slew Rate


Drive models

The Owner's Manual also lists the Drive models.

BB Pre (based on Xotic BB preamp)


  1. Based on: Xotic BB preamp, an overdrive pedal with a preamp stage. "BB" is an abbreviation of "Bluesbreaker".
  2. Cliff's comments:
    • "Works just like the real thing here. Tons of gain, too much IMO but I didn't design it." source

Bender Fuzz (based on Sola Sound/Vox Tone Bender)


  1. Based on: classic Tone Bender circuit, as used by Jimmy Page in Led Zeppelin's Whole Lotta Love.

Bit Crusher

  1. Custom Fractal Audio model, designed to warm up a sound or to deliberately degrade a signal, using the Bit Reduce and/or Sample Rate parameters.

Blackglass B7K (based on Darkglass Microtubes B7K)

  1. Based on: Darkglass Microtubes B7K (not the Ultra edition), an analog bass preamp, famous for its overdrive and transparency.

Blues OD (based on Marshall Bluesbreaker (Mk1)

  1. Based on: Marshall Bluesbreaker Mk1, which was designed to produce the mildly overdriven valve sound of the 2x12 Marshall combo amp used by Eric Clapton in John Mayall’s Bluesbreakers.

Esoteric ACB (based on Xotic AC Booster)


  1. Based on: Xotic AC Booster ("Almost Clean"), a thick, light-to-medium overdrive pedal.

Esoteric RCB (based on Xotic RC Booster v1)


  1. Based on: Xotic RC Booster v1 ("Real Clean"), a transparent boost pedal with additional gain en EQ.

Eternal Love (based on Lovepedal Eternity)


  1. Based on: Lovepedal Eternity, a pedal that covers clean boosting, overdrive and treble boosting.

Face Fuzz (based on Dallas Arbiter Fuzz Face)


  1. Based on: Dallas Arbiter Fuzz Face, made famous by Jimi Hendrix.

FAS Boost

  1. Custom Fractal Audio model, a clean boost, designed to boost vintage amps like Plexis.
  2. Cliff's comments:
    • "It's not based on anything. It's my take on an ideal boost pedal." source


  1. Custom Fractal Audio model, based on the Tube Screamer circuit, featuring LED clipping.

Fat Rat (based on modded Pro Co Rat)


  1. Based on: modified Pro Co RAT, for fuller and smoother sound.
  2. See Rat Dist model.

FET Boost

  1. Custom Fractal Audio model, gentle, smooth clipping with tone controls.

FET Preamp (based on BOSS FA-1 Fet Preamp)

  1. Probably based on: Boss FA-1 Fet Preamp, used by The Edge (U2).

Full OD (based on Fulltone Full-Drive 2)


  1. Based on: Fulltone Fulldrive 2, a thick overdrive pedal.
  2. Cliff's comments:
    • "The Full OD model is based on a Fulltone Fulldrive 2". source

Hard Fuzz

  1. Custom Fractal Audio model, a hard-clipping, 60s-style fuzz.

Master Fuzz (based on Gibson Maestro Fuzz-Tone FZ-1A)


  1. Based on: Gibson Maestro Fuzz Tone FZ-1A, as used in Satisfaction by The Rolling Stones.

Micro Boost (based on MXR Micro Amp)

  1. Based on: MXR Micro Amp Boost, a clean booster.

Mid Boost

  1. Custom Fractal Audio model, designed to boost the mids.

M-Zone Dist (based on BOSS MT-2 Metal Zone)


  1. Based on: Boss MT-2 Metal Zone, the metal pedal.

Octave Dist (based on Tycobrahe Octavia)


  1. Based on: Tycobrahe Octavia, an octave up fuzz.

Pi Fuzz (based on Electro-Harmonix Big Muff Pi)


  1. Based on: Electro-Harmonix Big Muff Pi fuzz.
  2. Cliff's comments:
    • "Our model uses a shelving filter but it's not based on a Ram's Head version." source

Plus Dist (based on MXR Distortion +)


  1. Based on: MXR Distortion +, designed to get more distortion from an already overdriven amp.

Rat Dist (based on Pro Co RAT)


  1. Based on: Pro Co Rat.
  2. Cliff's comments:
    • "The filter knob has been modeled but it works backwards." source

Ruckus (based on Suhr Riot)

  1. Based on: Suhr Riot distortion pedal.

SDD Preamp (based on preamp in Korg SDD-3000)

  1. Based on: preamp in Korg's rackmount SDD-3000 digital delay, used by The Edge.

Shimmer Drive

  1. Custom Fractal Audio model, designed to boost models of vintage amps (Plexi, Vox).
  2. Cliff's comments:
    • "The Shimmer Drive is my own creation. It is primarily intended to be used as a boost for Non-MV amps like AC-15/30's, Fenders and Plexis." source

Shred Dist (based on Marshall Shred Master)


  1. Based on: Marshall Shred Master.

Super OD (based on BOSS SD-1 Super OverDrive)


  1. Based on: BOSS SD-1 Super OverDrive, competitor to the Tube Screamer.

T808 Mod (based on modded Ibanez TS9 Tube Screamer)


  1. Based on: modded Tube Screamer, more bass, more gain, more transparency.
  2. Notes: see T808 OD model.

T808 OD (based on Ibanez TS9 Tube Screamer)


  1. Based on: Ibanez Tube Screamer TS9.

Tape Dist


  1. Based on: the clipping of an overdriven reel-to-reel Ampex tape deck.
  2. Cliff's comments:
    • "It's just a generic tape distortion simulator. I used an old Ampex EQ curve basically."
    • "The tape drive is meant to be used anywhere in the chain. I've been using it after the amp to fatten things up and it work really well for that. Be careful though, the drive block is mono so you can get phase issues if you put it after a stereo effect."

Timothy (based on Timmy overdrive by Paul Cochrane)

  1. Based on: Timmy pedal by Paul Cochrane, a transparent boost/overdrive pedal.
  2. Cliff's comments:
    • "The pedal has bass and treble controls. Low cut and Tone, respectively, are equivalent to these controls." source
    • "They are labeled Bass and Treble but they are Bass Cut and Treble Cut controls." source
    • "To get "flat" turn Low Cut all the way down and Tone all the way up." source

Treb Boost (based on a vintage treble booster)


  1. Based on: a silicon-based treble booster.
  2. Cliff's comments:
    • "Boost was a switch and engaged the effect. Set was the amount of boost and is equivalent to Drive." source

Tube Drv 3-knob (based on 3-knob Tube Driver)


  1. Based on: Tube Driver with 3 knobs, a pedal that contained a 12AX7 tube.
  2. Cliff's comments:
    • "The 3-knob version sounds very different than the 4-knob version." source
    • "Both of my actual pedals go silent with the Drive set to zero as would be expected looking at the design." source

Tube Drv 4-knob (based on 4-knob Tube Driver)


  1. Based on: Tube Driver with 4 knobs, a pedal that contained a 12AX7 tube.
  2. Cliff's comments:
    • "The idea with the 4-knob version is to use the tone controls on the EQ page and leave the single Tone knob at noon. You can still use the Tone knob if you want but the model is only accurate with the knob at noon."
    • "Both of my actual pedals go silent with the Drive set to zero as would be expected looking at the design." source

Zen Master (based on Hermida/Lovepedal Zendrive)


  1. Based on: Hermida/Lovepedal Zendrive, the Dumble-in-a-box pedal.
  2. To emulate the pedal's Voice control, use Low Cut. source

Pictures of the modeled pedals

Gallery of modeled pedals, by MDProd).

Simulating other drives