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Drive block

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Drive block.PNG

Available on which Fractal Audio products

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

X/Y and channels

  • Axe-Fx III: 4 channels
  • Axe-Fx II: X/Y
  • AX8: X/Y
  • FX8: X/Y

Yek's Guide to the Fractal Audio Drive models

Forum member Yek has written a comprehensive guide (PDF) that covers all Drive models, with accompanying showcase presets. Click on the image below.

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") with adjustable level: Neutral, T808, T808 Mod, Super OD, Full OD, AC Boost, Shimmer, FAS Boost.

A Graphic EQ has been added.

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

Drive blocks and CPU usage

The various Drive models take up different amounts of CPU. The numbers are listed in Yek's Guide to the Fractal Audio Drive models (PDF).

CPU usage is amplitude dependent on the Axe-Fx II, AX8 and FX8. This means that CPU usage will change when you hit the strings (even with the Drive block in bypassed state). This does not apply to the Axe-Fx III.

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

Tips and tricks

Fuzz, buffers and impedance

Forum member AustinBuddy recommends to set Input Impedance to 90K in presets with a fuzz as the first block. This doesn't apply to the AX8, because the AX8 has a fixed input impedance setting.

"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

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 Input Boost types: Drive models which are integrated in the Amp block, 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, Shimmer and FAS Boost. 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


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
EQ 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



The 10-band Graphic EQ was added in firmware Ares 1.16 for the Axe-Fx III.

The EQ is reset when changing the Drive type.

Pictures of the modeled pedals

Gallery of modeled pedals, by MDProd

Other drives and devices


Forum member Leon Todd (aka "2112") made an in-depth tutorial about tweaking each Drive model.

Drive models

BB Pre (based on Xotic BB preamp)


Based on Xotic's BB preamp, an overdrive pedal with a preamp stage. "BB" is an abbreviation of "Bluesbreaker".

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


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

Bit Crusher

A 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)

Based on the Darkglass Microtubes B7K, an analog bass preamp which is famous for its overdrive and transparency.

Blues OD (based on Marshall Bluesbreaker (Mk1)

Based on Marshall's Bluesbreaker Mk1 pedal, 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)


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

Esoteric RCB (based on Xotic RC Booster v1)


Based on Xotic's RC Booster v1 ("Real Clean"), a transparent boost pedal with gain and EQ controls.

Eternal Love (based on Lovepedal Eternity)


Based on Lovepedal's Eternity, a pedal that covers clean boosting, overdrive and treble boosting.

Face Fuzz (based on Dallas Arbiter Fuzz Face)


Based on a Dallas Arbiter Fuzz Face, the fuzz pedal that Jimi Hendrix used.

FAS Boost

A custom Fractal Audio model that provides a clean boost, designed to boost vintage amps like Plexis.


A custom Fractal Audio model, based on the Tube Screamer circuit and featuring LED clipping.

Fat Rat (based on modded Pro Co Rat)


Based on a modified Pro Co RAT, providing fuller and smoother sound. See Rat Dist model.

FET Boost

A custom Fractal Audio model, providing gentle and smooth clipping, with tone controls.

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

Similar to the Boss FA-1 Fet Preamp, a favorite pedal of The Edge (U2).

Full OD (based on Fulltone Full-Drive 2)


Based on Fulltone's Fulldrive 2, a thick overdrive pedal.

Hard Fuzz

A custom Fractal Audio model, providing a hard-clipping, 60s-style fuzz.

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


Based on Gibson's Maestro Fuzz Tone FZ-1A, used by Keith Richards in Satisfaction.

Micro Boost (based on MXR Micro Amp)

Based on MXR's Micro Amp Boost, a clean boost.

Mid Boost

A custom Fractal Audio model, boosting the mids.

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


Based on a Boss MT-2 Metal Zone.

Octave Dist (based on Tycobrahe Octavia)


Based on a Tycobrahe Octavia, an octave-up fuzz.

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


Based on an Electro-Harmonix Big Muff Pi fuzz.

Plus Dist (based on MXR Distortion +)


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

Rat Dist (based on Pro Co RAT)


Based on a Pro Co Rat.

Ruckus (based on Suhr Riot)

Based on Suhr's Riot distortion pedal.

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

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

Shimmer Drive

A custom Fractal Audio model, designed to boost models of vintage amps (Plexi, Vox).

Shred Dist (based on Marshall Shred Master)


Based on Marshall's Shred Master.

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


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

T808 Mod (based on modded Ibanez TS9 Tube Screamer)


Based on a modded Tube Screamer, providing more bass, more gain, more transparency.

T808 OD (based on Ibanez TS9 Tube Screamer)


Based on an Ibanez Tube Screamer TS9 (actually a TS9DX in TS9 mode).

Tape Dist


Simulating the clipping of an overdriven reel-to-reel Ampex tape deck.

Timothy (based on Timmy overdrive by Paul Cochrane)

Based on the Timmy pedal by Paul Cochrane, a transparent boost/overdrive pedal.

Treb Boost (based on a vintage treble booster)


Based on a silicon-based treble booster.

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


Based on the Tube Driver with 3 knobs, a pedal with a 12AX7 tube.

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


Based on the Tube Driver with 4 knobs, a pedal with a 12AX7 tube.

Zen Master (based on Hermida/Lovepedal Zendrive)


Based on the Hermida/Lovepedal Zendrive, a "Dumble-in-a-box".