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Axe FX vs. real amp

HiveMind

New Member
Have any of you who own an actual amp modeled in the Axe performed the following A/B test?

1) Set all real amp and model controls identically
2) connect axe to fx return of amp
3) configure axe with cab and power amp sims off
4) match volumes and compare

Does the signal from the axe truly equate to the signal at the fx send jack of the amp? Please relate your experiences with this, as I no longer have any examples to compare.
 

firmani99

Inspired
I have never done it exactly like that. I have never turned off the amp sims. But I have run a Mark IV side by side with the axe fx and a crown power amp into the same cab. I've match the controls and I can get them to sound pretty much the same. All with the controls at relatively the same positions. Some of the eq sliders might have been set marginally different but not much at all. I have gotten them so close that in a blind test, I bet I wouldnt be able to tell which is which.
 

barhrecords

Axe-Master
I've done something similar but not using amps with an efx loop.

I've A/B running into the front of the amp -> guitar cab vs. Fractal -> power amp -> same guitar cab.

I tested a vintage Marshall JCM800 -> Marshall 2x12 closed back cab, vintage Fender Princeton, vintage Fender Twin, vintage Fender Bassman.

This was many FW revisions ago.

I was able to get really close in all cases. I did not rely on the settings matching the amps exactly though. I don't really care if the "numbers" match. I was just using my ears.

I used the old amp matching video Cliff did as a guide. It explains how to match the model to the amp's gain.
 

Clockwork Creep

Power User
What matters is not whether it sounds the same, but whether it sounds good.
If it sounds 5% like a different amp than the reference, but still sounds like a real bad ass tube amp, what's the problem?
Anyway, can't do the test.
But I've heard plenty of similar comparisons on youtube, with really old firmware and it sounded really close, at the point of me having no idea what is what. Using tone matching, It can make it even harder to distinguish...
I wonder how it compares this time around with quantum firmware...
 
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Matt_B_77

Power User
If one compares an Axe-FX amp model to its real world counterpart then the tolerances present in real-world amp (resistors, caps, pots, tubes) must also be taken into consideration.

These analog differences makes the odds of the two sounding exactly the same are very low but they will sound incredibly similar.
 

mr_fender

Fractal Fanatic
I've done this with my Boogie Mark IV and the results were close enough that my Mark IV and cabs have done little more than collect dust since I got the Axe.
 

Severed

Power User
I thought about it when first considering moving to the fractal. After a month with the Axe FX II though my desire to 100% replicate the real counterpart completely vanished. IMHO the models in the Axe not only compare authentically, but they surpass the real thing and allow you to take it beyond and actually get the tone you want instead of settling for the amps capabilities.
 

s0c9

Moderator
Moderator
my question to the OP would be "How do you think Cliff models the amps included in the AxeFx?"
There have been numerous blind A/B tests conducted with the modeled amps.. and the results of most (IIRC) were that folks often chose the FAS version over the original.
IMHO - it's a non-issue.
 

mr_fender

Fractal Fanatic
Agreed. Axe is so much more flexible than any physical tube amp. I've never been 100% satisfied with any tube amp. There was always something that could have been better. Great leads but crappy clean or great clean but mushy overdrive, or great tones but noisy or crappy effect loop, etc., etc.. The Axe solves all that for me. It's like having a 200 channel all tube amp that is nearly infinitely tweakable. Plus I get all the killer effects I could want as a bonus. I used to pour over websites and magazines checking out all the latest amps and stompboxes. Since the Axe, I have zero desire for anything else except maybe another CLR cab and maybe a better MIDI controller. Wish I could say the same for guitars. I always want more guitars.
 

JayCM800XL

Experienced
On my home set up I have the Axe going SPIDIF to my interface/monitors and from Output 2 to a power-amp/cab(left side of a 4x12). A Marshall JCM800 goes to the other half of the 4x12. That's how I tweak so that my main preset sounds 99% like the tube amp, either thru monitors or speaker cabs.
 

guitarmike

Experienced
Been a long time since I did it just like that. The controls are not 1:1 but the tone can be the same using basic controls. At this time I am getting better tones running the axe frfr. Very little tweaking required although there are some presets that require the bright cap be off, imho. I also tweak the speaker page on some amps, typically decrease hi res on some hi gain amps. The frfr source is important but I'm using a $400 EV speaker and loving it. I have been around a played a lot of amps and the axe fx is the real deal.
 

Kyle.E.Woyote

Inspired
Agreed with many here, my only concern with the AxeFx is getting a good tone, authenticity is by the way side....sorry for off the rails there..

I own a Jsx Peavey (not modeled) and a '87 Silver Jubilee(modeled) I haven't done a side by side of it, but it must be damn close if my memory (ears) aren't lying to me when I do mess with the modeled version!
 

GreatGreen

Power User
Yes, OP.

If you turn off poweramp and cab modeling, the Axe-Fx will replicate the exact sound of the real amp's preamp such that plugging the Axe-Fx into the real amp's physical poweramp and cab sounds completely natural and, in the tests I've personally run, almost indistinguishable from the real thing.
 
I have never done it exactly like that. I have never turned off the amp sims. But I have run a Mark IV side by side with the axe fx and a crown power amp into the same cab. I've match the controls and I can get them to sound pretty much the same. All with the controls at relatively the same positions. Some of the eq sliders might have been set marginally different but not much at all. I have gotten them so close that in a blind test, I bet I wouldnt be able to tell which is which.
This is the thing I've found the most impressive about the AxeFx vs. other modeling units I have tried over the years. I've got a pretty large tube amp collection that contains what I consider the building blocks of guitar sound (various amps by Fender, Marshall, Vox, Mesa, plus a few boutique offerings. 19 amps in all) and when I their respective amp block with the right cabinet block in the AxeFx and I set the tone controls the same the same way on my amp block that I have them set on my amp, they're extremely close in sound to the real thing without any additional tweaking.

No modeling unit I've used in the last 20 years has been able to do that. I would always end up having to go to great lengths to get something even remotely remotely close to my actual amp and after hours of tweaking still not be happy with it.

With the AxeFx, I pick an amp and cab...use my favorite settings that I use on my tube amp and within a couple of minutes I'm like 95% there and with a little additional tweaking on the more advanced settings I'm so close that I would have a hard time telling the two apart in a blind listening test.
 

zenaxe

Fractal Fanatic
I've really lost my curiosity about this issue.

From using my ears, the Fractal sounds great, plays great.... now on with the music :)
+1. Try it with two "identical" amps first and see how that goes; then try to justify why you think that experiment would be meaningful.
 

Pinkycramps

Experienced
OP, have you ever taken 3 different vintage JCM 800's and set them side by side with a switching unit, set all the controls identically, and A/B'd them? They are not the same. Just because you have a Mark IV, or a JCM 800, you don't have Cliff's Mark IV or JCM 800, so this test is pretty doomed from the start.
 

mongey

Inspired
In reality I think the fractal/matrix combo is probably 90%to 95% there on pure high gain sounds compared to my my dual recto through a guitar cab.

but for that 5 to 10% I get unlimited effects, scene changes= no tap dancing , much better clean channel options . and all the other amps to use as well . plus the ability to use IR's and DI when needed

more than worth it
 

casper12

New Member

I did a comparison with a buddy of mine last year and the results were astounding. I can't remember what firmware this was, but it I can only imagine it'd be even closer if I tried this with quantum. In the video, Preset 11 is just the dry Mark V (Mark IV mode) going into my compact rectifier 2x12, and Preset 12 is the USA Lead Bright on the Axe going into the Mark V's power amp and cab, no cab sims.

EDIT: Also, just to clarify, this is without any tone matching, we just tweaked until it sounded as close as it could get.
 
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