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Fractal Audio AMP models: FAS models


* EDIT: Up-to-date information is available in Yek's Guide to the Fractal Audio Amplifier Models *

The FAS models

We already discussed some “custom” amp models. These virtual amps have no real-life equivalents. They solely exist within Axe-Fx II and AX8, surpassing limitations of traditional amps. Some are based on real amps, containing Cliff’s ideas and improvements. And some were just born by accident.

There are no “rules” when it comes to cab choices.

FAS 6160: based on the PVH 6160 Block model (EVH 5150). According to Fractal Audio, this model is less fizzy than the original EVH 5150, with a bouncier feel.

FAS BASS: added in firmware 13. Fractal Audio’s implementation of a great bass amp. This model features active controls.

FAS BROOTALZ: added in firmware 14. brings teh brootalz! Great aggressive high gain amp. If you hear some resemblance to the Savage, you’re right.

Cliff: “This amp was an accident. I was working on the Savage model and accidentally used the input stage from an SLO100. So it's the front end of an SLO100 with the back end of a Savage. It's probably an SLO100 power amp too but I'd have to check.”​

FAS BROWN: already discussed here.

FAS CLASS-A: added in firmware 12. Another amp model that was born by accident.

“A “Blackface” preamp into a cathode-biased 6L6 power amp with no negative feedback. This was a happy accident when originally modeling the Carr Rambler in the beta version of this release. Several mistakes were made in the model prior to MIMIC’ing the amp but the model was so well liked that we decided to make it into its own custom amp model."​

FAS CRUNCH: added in firmware 9. Fractal Audio's take on the ultimate British-sounding amp (read: Plexi). More dynamic/open plus more gain.

FAS HOT ROD: added in Quantum 1. Cliff’s idea of the ideal modded Marshall.

“FAS Hot Rod is my version of what a modded Marshall should be. I find the BE/HBE a little too boomy and scooped. Bogners are too dark. Splawns don't have enough compression. Etc. So it's my take on a hot-rodded Marshall tone.”​

FAS LEAD 1: a neutral high-gain lead tone, with a tight midrange.

FAS LEAD 2: a hot-rodded British lead sound with a tonestack by Custom Audio Electronics.

FAS MODERN: a high gain hybrid tone that’s equally suited to modern rhythm and lead work. This is a very popular model, used by among others Periphery and Andee Blacksugar.

“This model is my interpretation of the ideal modern metal tone. In the digital realm we are not constrained by the limitations that face tube amp designers so we are free to implement designs that would be nearly impossible with a tube amp. The Axe-Fx II modeling includes a variety of general purpose filters that I can place anywhere in the signal path. So I put some second-order filters in there to tighten up the tone. Implementing second-order filters in a real tube amp is difficult and costly so is rarely seen.”​

FAS MODERN II: added in firmware 10. Tighter version of the popular FAS Modern model with a 5150-style bass boost in the tone stack. This model has so much gain, that it doesn't hurt to turn that down to say around 3. And turning off Bright helps to shave off its harsh tone.

FAS MODERN III: added in firmware 17. Similar to a Recto but with tighter bass and a cathode-biased power amp. Watch out if you select this, it is LOUD! Use one of the 4x12 Recto stock cabs.

FAS RHYTHM: combines the best features of the British (Marshall) and USA (Mesa) crunch models.

FAS WRECK: this is original WRECKER 1 model from the Axe-Fx Standard/Ultra.
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I'm taking a few days off. Enough models to keep you going in the meantime.
I will miss this daily read, but I will use the time to go back from the beginning and read them again to catch the things I missed the first time around. You sir ARE the man and have done some really great work here.


Yek, these are amazing! I read them all and enjoy them, and you have opened my eyes to things I now use joyfully. Your contributions to this community are a huge blessing! A thousand thanks!

flipp jackson

New Member
maybe a dumb question about these models:

do all of these models benefit from the latest firmware modeling improvements? like for example the trainwreck custom model was from the ultra or whatever but does it have the added benefits of quantum modeling (assuming you have the later firmware of course)?


Power User
Just went back to FAS Modern, which I always found a little too gainy in the past... Not sure if it was the firmwares since or the lower output pickups I'm using now, but it was amazing! Could not get enough.

Everyone play with a FAS model again, stat!


I think the "FAS Crunch" will be my new go-to Marshall. It really is in the sweet spot between the 800, modded 800's, and Plexis. Just turn up the gain and maybe turn off the bright switch and you're done.

I'll have to spend some time on the "Hot Rod" as well. Sounds right up my alley.

Would be neat to have some clean ones as well, although not sure what hasn't been covered!
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