Axe-Fx II (legacy)

The Axe-Fx II preamp and effects processor has been discontinued. The contents of this page are frozen and will not be updated.

References

• Website
• Owner's Manual
• User forum
• Wiki

Pictures of Axe-Fx II rigs

Owners of an Axe-Fx II proudly show their rigs

About the Axe-Fx II

Discontinued

The Axe-Fx II series has been discontinued.

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[1] All gone. DSP is discontinued and no more left in supply chain.

[2] All that is there is some of the modeling improvements. It was all I could do to get that to run and fit. I kept running out of memory. There simply isn't any more room for more stuff. The Axe-Fx II design is nearly 8 years old now. The board only has 256M of memory. Contrast this to the Axe-Fx III which has 4G.

The last firmware version for the Axe-Fx II, "Ares 2.00", was released in September 2019.

[3] The Axe-Fx II is EOL. There will be no further firmware updates.

Frequency response

The frequency response of the Axe-Fx is flat.

Aliasing

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[4] Aliasing is solely something that happens in sampled-data systems (what we call "digital"). A good example of aliasing is the old wagon wheel spinning backwards at the movie theater. This is because a film is actually a sampled-data system. A tube amp is not a sampled-data system.

See the Tests and discussion and Tests of aliasing performance threads for more information.

Screen

If there's a display problem, check the ribbon cable inside the Axe-Fx.

The Axe-Fx II XL+ has an updated LCD display and display controller.

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[5] An occasional flicker when hooked up to USB is not unusual. This is due to the screen redraw being interrupted by the USB thread.

[6] Display flickering on the tuner is normal. Some do it more than other. It's just the nature of the display. The display uses a ping-pong buffer. One page is updated while the other is displayed. Then the pages are switched. Some flickering can occur during the page switch. The reason it is noticeable more on the tuner is that the display is updated more frequently.

Power

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[7] The power supply is quite over-spec'd. The unit only requires about 25W but I spec'd a 40W supply to ensure longevity under difficult operating conditions.

[8] The power supply is an Artesyn LPT-42 (also sold under Astec and Emerson labels). Should be readily available in EU.

Use the front panel knob to switch the unit on or off. Or just disconnect the power as often as you want, it doesn't hurt the Axe-Fx II. Remember that presets need to be saved first. All other changes are saved automatically. See "I take many breaks; should I leave the equipment on?" for more information.

To avoid the "pop" when powering up the Axe-Fx II XL+, turn down its level knobs.

Possible issues when cycling power:

• If you use a power conditioner, try powering up the Axe-Fx II AFTER switching on the power conditioner.
• If a corrupt preset causes the Axe-Fx II to freeze during startup, hold Recall while powering up. This make the Axe-Fx II skip that preset and start with an empty one. If this doesn't help, verify that the preset doesn't link to a corrupt user cab.

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Low voltage:
Modelers are like synths in that regard. They will sound the same but if the voltage gets too low they may start acting weird, shutting down, etc. Modelers are really just specialized computers. If the voltage gets too low they can malfunction.

• If the Axe-Fx won't boot anymore, contact Fractal Audio Support. You may need an emergency EPROM which you can use to boot the Axe-Fx II (Mark I or II). The Axe-Fx II XL and XL+ have a built-in emergency EPROM: hold down Page Left and Page Right while cycling power.
• If the Axe-Fx crashes after having installed new firmware , try this: pull the battery, install firmware again, reinstall the battery.
• To avoid the "pop" when powering up, start the Axe-Fx II before the amplifier. And vice versa when shutting things down. The XL+ surpresses the "pop" at startup.

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[9] The power supply has an on-board fuse.

Fan

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The fan was changed to 80mm quite some time ago. The XL and XL+ have the fan mounted to the motherboard which eliminates the coupling into the cover which further reduces noise. The XL and XL+ are nearly silent.

Battery

The Axe-Fx II Mark I and II use a battery, expected to last over 10 years. When the battery dies, presets will get corrupt and disappear. Install a fresh CR2450 Lithium battery.

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[10] Replacing the battery does not void the warranty.

[11] The XL and XL+ have a battery. It's a CR2032 IIRC.

Encoder wheel

If your encoder (value wheel) behaves erratically, it may be broken.

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[12] The XL and the XL+ both use optical encoders. The Mark I and Mark II have mechanical encoders.

CAT5 connector

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About accidentally plugging USB into CAT5 connector:
[13] Mark II, XL and XL+ models have a PTC fuse on the jack to protect against this.

Microphonic behavior

Tapping the housing may be amplified through the unit.

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[14] Anything with enough gain will be microphonic. It's primarily due to the circuit board and any ceramic capacitors. The ceramic caps are piezoelectric so they will convert any acoustical energy into electrical energy. The circuit boards flex (microscopically) which causes strain in the traces which is converted to electrical signals. The Axe-Fx II strives to minimize this. The Mark II is comparable to most other modeler products. The XL has nearly completely eliminated this due to the use of PPS film caps in critical locations and a stiffer board mounting design.

[15] Any circuit will be microphonic to some degree due to the piezoelectric nature of capacitors. When you apply 60 dB or more of gain with an amp block you're going to amplify that.

Specifications XL+

Dimensions and weight:

• 19” x 3.5” x 14.25” (483 x 88 x 362mm)
• Weight: 14.75 lbs (6.7 kg)

Processors:

• Two TigerSHARCs. One dedicated to amp and cab modeling, the other to everything else

LCD display:

• Screen: 160 x 80

Backup battery:

• CR-2032

I/O:

• Sample rate and USB Audio: 48kHz (fixed)
• Input impedance: 1 MegaOhm (variable)
• Output impedance: 600 Ohms AC
• Headphones output: one
• Instrument input: 1/4” phone jack, unbalanced, max +16 dBu (conditioned for guitar use)
• Rear input: 1/4” phone jack, unbalanced, max +20 dBu
• Analog outputs: 1/4” phone jack unbalanced (hum-canceling), XLR balanced (for main output) 600 ohm, max output +20 dBu
• Digital I/O: RCA Coaxial Type for SPDIF I/O, XLR for AES I/O
• MIDI: 7-pin DIN MIDI IN (pins 6 & 7 connected to phantom power in jack), 5-pin MIDI OUT and 5-pin MIDI THRU
• Pedals: 2x 1/4” TRS phone jack, momentary or latching, 10–100kΩ max, linear taper expression type
• MFC-101: RJ-45 Ethernet/EtherCON or FASLINK (1x XLR)
• Phantom power: female 2.5mm jack, do not connect adapters with a rating higher than 1A (1000ma)

Power:

• Built-in switchable AC power supply

More in the Owner's Manual

Differences between Axe-Fx II models

Axe-Fx II Mark II

The original model has been replaced with a Mark II model in October 2012. The main change is the addition of an EtherCon jack, replacing the standard RJ45 port for connecting an MFC-101. This is in line with the MFC-101 Mark II version. EtherCon offers built-in strain protection to guard against damage from CAT5 cable pulls or jolts. It's backward compatible with standard Ethernet cables, however EtherCon is recommended for harsh environments. Another change is that Mark II models are protected against inserting the ethernet cable into the USB port. [16]

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[17] The connectors are backward and forward compatible. The problem was that people were breaking the connectors, especially on the MFC. So we changed them to more durable connectors.

[18] The only difference between MK I and MK II are some vents in the chassis, larger fan and an Ethercon jack instead of an Ethernet jack. Otherwise the hardware is identical. I can see the XL possibly sounding a bit better and the XL+ sounding even better than the XL but there should be negligible difference between a Mark I and a Mark II.

Due to space limitations in the Mark I/II BOOTROM, firmware Quantum 5.00 and later is not backwards compatible with presets created prior to firmware version 15.08. This limitation only exists for the Mark I/II. XL and XL+ still maintain backward compatibility.

Axe-Fx II XL

Announced in January 2014 and available from March 2014. It was replaced with the Axe-Fx II XL+.

The XL has the same DSP and amp modeling capabilities as the Axe-Fx II Mark II, but offers expanded memory, new I/O ports, and other upgrades detailed below:

• Built-in FASLINK port for connection to MFC-101 Mark III over conventional XLR cables.
• Dedicated MIDI IN, OUT, and THRU jacks (vs. shared OUT/THRU in the Mark II).
• Two onboard PEDAL jacks (vs. one in the Mark II).
• Primary VALUE entry via (powered) optical encoder with a lifespan of 1,000,000+ rotations.
• “Secret Sauce III” instrument input features an even lower noise floor.
• 128 Mb of non-volatile Super-FLASH memory allows for storage of up to 512 presets (increased in later firmware) and 512 user cabinets (increased in later firmware) with copious reserves for future expansion.
• Double-capacity preset size allows for expanded functionality including X/Y switching on more blocks and more instances of effects. Note: any blocks that have X/Y on the XL but not on the Mark II will not import the bypass state as that is stored differently. You need to manually adjust the bypass state after import [19].
• Built-in backup firmware allows recovery in the event of complications during update.
• Backward compatibility with Axe-Fx II Mark I/II presets via Axe-Edit software.
• The XL can import presets from the Axe-Fx II/Mk II but not vice versa.
• The Axe-Fx II XL has 159 stock cabs.

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About the Axe-Fx II XL:

• The primary impetus for the XL was the FASLINK port. Since I had to develop a new mainboard to support this I figured why not put in some of the other requests we get from the power users.
• The additional memory is FLASH which is EPROM not RAM. This will not increase the looper time as the amount of RAM has not changed.
• The type of FLASH memory is "Super-FLASH" which is an expensive, high-reliability memory. It can be erased hundreds of thousands of times without wearout or slowdown. This prevents the need to wear-level the memory and the dreaded "Tuning Memory" stuff.
• There is no longer any SRAM for preset storage. All presets are stored in FLASH.
• There is still a small SRAM for storage of system information that requires a battery. You can still back your system up to FLASH. If the battery dies you won't lose your presets and hopefully you've backed up your system.
• There is enough FLASH memory to store 1024 presets and 1024 user cabs but I'm reserving half the memory for future upgrades.
• The "Special Sauce III" uses a combination of things to get a lower noise floor. One of these things is new, premium Burr-Brown op-amps in the signal path which have extremely low noise and distortion (and are very expensive). As always I don't design stuff to be cheap, I design it to be good.
• The optical encoder requires power and therefore can not be retrofitted into a Mark I/II. Also the shaft and bushing size are different so it doesn't fit anyways.
• UltraRes is not specific to the XL.
• All algorithms will be identical between the Mark I/II and XL. They all share the same code base. Any enhancements/improvements will benefit all models except when aforementioned features are not available.

[20] The MFC-101 stores 384 presets. The Axe-Fx II Mark I/II also store 384 presets. The XL stores 512 presets (firmware 15.04: 768) and maybe someday 1024. Many MIDI controllers only store 128 presets. There is no correlation between the number of presets on a MIDI controller and the device being controlled. This is not a bug, mistake or deception.

Axe-Fx II XL+

Available from March 2015. Compared to the XL, it has another LCD display/controller and slightly lower noise.

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[21] The XL+ has semi-automatic pop suppression. It's automatic on power on. If you turn down the Output Level knob before turning the power off it will activate the power off suppression. Even if you don't the pop is somewhat suppressed as the there are output clamps that activate when the voltage drops below a certain threshold.

[22] The XL+ is slightly quieter. It has some minor improvements to the front end electronics. It's not a difference we feel is worth crowing about as the XL is already very quiet. The data bus is also slightly improved which yields a small reduction in base CPU usage. And finally there is power up/down pop protection on the outputs. We could've made a big deal about these things but they're minor and not significant improvements over the previous models. They're just little tweaks. We had to redesign the board for the new LCD so we took the opportunity to tweak a few things.

[23] The XL+ uses slightly less CPU because of a more efficient video path.

[24] The XL+ shares the same amazing low-noise architecture of the FX8. I regularly use my XL+ in 4CM as this is part of the modeling process. It's the quietest device I've ever tried in 4CM.

[25] Pop protection on power off requires turning the Level knob(s) all the way down. If you don't you'll still get a little pop but not enough to damage speakers.

[26] The Boot ROM is four times larger.

[27] The XL+ uses a higher quality input buffer than the Mark I/II.

Manufacturing

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Our current production model is to source the chassis from China. The PCAs are made in USA and final assembly and QC are done in USA.

The Axe-Fx II is about 80% domestic content.

The Axe-Fx II is a no-compromise product and that is reflected in the price. Most, if not all, manufacturers use, for example, TL074 op-amps for the analog I/O. Those are inexpensive, quad, FET input op-amps with okay performance. They cost about a ten cents each. We use high-end Analog Devices products that cost about a dollar for a dual. These are reference-grade amps. We use film capacitors where possible in critical signal path locations. Again, much more expensive but reference-grade performance. The A/D and D/A converters are reference-grade. Even the circuit board has gold-plated pads as compared to tin.

[28] We use the flagship Cirrus converters along with Analog Devices "Butler" op-amps. Film caps where possible. All I/O to the converters is balanced to provide optimum SNR and distortion performance. One of our op-amps costs ten times what is commonly found in other products.

[29] I'd be willing to put the converters and circuitry up against the best names in the industry.

[30] It uses better converters than a Metric Halo. That said, many converters color the sound and people interpret that as "better". The Axe-Fx DACs are designed to be completely neutral.

[31] The Axe-Fx II, FX8 and AX8 use heavy-duty steel chassis, audiophile-grade op-amps, "flagship" converters, full-differential analog paths, PPS (poly-phenylene sulfide) film caps, ENIG (electroless nickel, immersion gold) circuit boards, etc.

[32] One of the Axe-Fx's DSPs is more powerful than both DSPs combined in the Helix. Our tests show that the TigerSHARC DSP used in the Axe-Fx is over twice as fast as the DSP used in the Helix clock-for-clock . Now add that our DSP is clocked 50% higher the net power is about three times greater. So a single TigerSHARC is about 50% faster than both DSPs combined on the Helix. Yes, if we decided to use both DSPs for effects then you would be able to run more effects. 99% of our customers buy the unit for amp modeling so it doesn't make sense to invest the time and resources to making this possible. Our algorithms are studio-quality and use more processing power than competing products. We've always been about quality over quantity. For example, our variable delay algorithm (chorus, flanger, etc.) uses poly-phase interpolation. EVERY competing product I have tested uses simple linear interpolation (or occasionally polynomial interpolation) which is far less computationally intensive but doesn't sound as good. This is demonstrable and measurable.

[33] We do not use "China parts". Our Contract Manufacturer (who is located in the USA) buys the parts we specify from domestic distributors. Typically Arrow, Avnet, Mouser, Digi-Key, etc. Many of those parts ARE made in China as well as Mexico, Taiwan, Vietnam, etc. There are virtually zero electronic component factories in the US. All the major electronic manufacturers have set up factories outside the US because labor is far cheaper and tax laws are more favorable. We also specify premium grade parts unlike most manufacturers in this market space. I challenge anyone to compare the components used in our products to the components used by other manufacturers. We always use reference-grade converters, op-amps, film caps, etc. because it matters and you can hear it. We don't choose the lowest bidder, we choose the best quality. Our sheet metal and related chassis components are sourced from China as there are really no good sources of sheet metal fabrication left in the US. It's also the most labor intensive part of production but has no bearing on the sound quality.

[34] The input circuit of Fractal products mimics the input of a tube amp very accurately: (see graph)

[35] The TigerSHARC architecture is vastly superior to the SHARC, and it's a shame it has been discontinued. In our tests a TigerSHARC performs about 50% faster clock-for-clock. Then factor in the higher clock speed and it's about twice as fast. See here for independent benchmarks: http://www.bdti.com/MyBDTI/bdtimark/chip_float_scores.pdf . The newest SHARCs are the same as the 213xx except they have the FIR accelerator. As one can see a TigerSHARC (Axe-Fx's use the ADSP-TS201S) is about twice as fast. IIRC the current Amplifire uses two 21369 so this new product is likely using two or more 2146x as the accelerator is not available on the 2136x series.

There are a several inaccuracies in StudioDevil's post. First of all the TigerSHARC has a more modern core and much better architecture (larger register file, wider buses, better DAG units, etc). It can do six floating point operations per clock. In practice this is two multiplies, two adds and two store/fetch instructions. This means a 4096 point IR only requires 2048 clock cycles.

Secondly the TigerSHARC has a much wider bus than a SHARC. The TigerSHARC has a 512 bit bus whereas a SHARC has a 128 bit bus. The TS can move data around much faster and pipeline stalls due to bus contention are far less frequent. It can load or store eight words in a single clock cycle whereas a SHARC is hard pressed to do two.

The TS also has a LOT more on-chip memory. A TS has 24 Mbits of on-chip memory compared to 5 Mbits for the best SHARC. This means more code/data in fast memory and less stalls waiting for data access. Also the TS has a superior cache unit which caches both instructions and data, as opposed to instructions only on a SHARC. There are numerous other improvements as well including better DMA engine, better interrupt handling, vastly superior 40-bit floating point support (which we use for amp modeling), etc., etc.

Having written hundreds of thousands of lines of code for both (including coding the SHARC's FIR accelerator) my experience is that the TS is a much better chip but it is much more expensive. We moved to SHARCs for our floor processors for a variety of reasons but performance was definitely not one of them. The FIR accelerator is nice and all but it only applies to cab modeling which is a small percentage of a typical preset. On an Axe-Fx II a stereo Hi-Res cab block only uses 11% of the DSP. On an AX-8 it's still a couple percent as the accelerator doesn't handle everything needed in the block. So the net savings is less than 10%. The rest of the effects then run about twice as fast which means almost twice as many effects per preset on an Axe-Fx compared to an AX-8.

While "all about the code" has some merit, in reality it's "all about a lot of things" including the architecture and clock speed. Algorithm complexity is also very important and it becomes diminishing returns (i.e. it takes twice as much CPU to improve the sound quality 10%). If it were just about the code everyone would still be using the original 33 MHz SHARCs. The TigerSHARC enjoyed a long run as the best DSP on the market but, alas, all good things must come to an end. The good news is that Atomic, Fractal and Line6 are all using the same DSP family in their respective floor products so it's highly unlikely Analog Devices will discontinue them and there are now more choices for the consumer.

Processing

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[36] All the amps have the same "latency" and it is so low as to be imperceptible. The total system latency is about 1ms.

Axe-Edit

Read Editors for more information.

Firmware

See these for more information:

• Firmware
• Firmware release notes - Axe-Fx II_(legacy)
• Emergency Boot Recovery

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[37] The Axe-Fx I and II had a lot of hand-coded assembly as do the FM3/9. The DSP used in the Axe-Fx III is very difficult to write assembly for. It's a VLIW processor so it's best to use the optimizing compiler and let it do the work. There are a bunch of intrinsics that we use that are essentially assembly instructions but you can call them from C/C++.

I/O

• IN 1 (INSTRUMENT) – 1/4” phone jack, unbalanced, max +16dBu, conditioned for guitar use, instrument level
• IN 1 (rear) – 1/4” phone jack, unbalanced, max +20dBu
• IN 2 (FX RTN) – 1/4", L/R, balanced, 1 Megaohm, max. 20dBu
• OUT 1 MAIN – XLR, balanced, 600 ohm, max. output +20dBu
• OUT 1 MAIN – 1/4” phone jack, unbalanced (hum-canceling)
• OUT 2 (FX SEND) – 1/4", L/R, unbalanced, Humbuster, 600 ohm, max. 20dBu
• Digital I/O – SPDIF (RCA Coaxial), AES (XLR), USB Audio

Read these for more information:

• Expression pedals and external switches
• MIDI
• USB
• FASLINK

Pedal ports

The Mark I and II models have a single pedal port. The XL and XL+ have two. An external switch can be a momentary or latching one, and uses either a TS or TRS cable.

Use the Setup menu to tell the hardware what type of external switch you're connecting:

• When a latching (aka "toggle") switch is connected, set TYPE to “LATCHING”
• When a momentary switch (such as a sustain pedal) is connected, you have two options:
  1. Set TYPE to “MOMENTARY” and the device will recognize alternate stomps as ON and OFF, creating a “virtual” latching footswitch
  2. Set TYPE to “CONTINUOUS” if you want the switch to turn on when you press, and off when you release it

Presets

Number of presets:

Axe-Fx II Mark I and II — 384
Axe-Fx II XL and XL+ — 768

See Factory presets for more information.

Effects list

Click on the image below:

System reset

Read Reset system parameters for more information.

Buttons, knobs and switches

X/Y Quick-Jump buttons

Pressing the X and Y buttons, while in the Layout screen, lets you jump to a block's Edit mode. You specify which block that is in the Setup menu. This enables you to, for example, quickly display the basic controls of the Amp block.

ABCD Quick-Control knobs

The ABCD knobs on the front panel work as modifiers in the Control > Manual screen.

Knob A is also used to switch scenes in the Recall and Layout screen.

The ABCD knobs can be used as tone and gain controls (Drive, Bass, Middle, Treble) in the AMP block's first page. An easy way to quickly access these, is assigning "X" on the front panel to the Amp block in the Setup menu. A quick press on X will take you to the page with tone controls and you can use the ABCD knobs for quick editing.

The ABCD knobs on the AMP block's Type page can be used to control certain parameters. However, when modifiers are attached to those parameters, the ABCD knobs will control the modifers.

Shortcuts

• Hold ENTER on the Layout page to keep adding shunts.
• Press Enter in a block's Edit menu to move to the next block on the grid.
• Press Enter in the Global EQ or Amp block's GEQ page to flatten the sliders.
• Press Enter in the Sequencer to randomize the values.
• Double-press Bypass to reset the entire block.
• Double-press Eff.Bypass to open the Global Blocks menu.
• Page Right on the Recall screen: copy and paste effect settings with Recall Effect.

Switch presets

• Value wheel
• Cursors or Page buttons
• Foot controller
• MIDI

More about Presets...

Switch scenes

• Turn the "A" knob to switch between scenes on the hardware
• Foot controller
• MIDI

More about Scenes...

Switch between X/Y

• Use the X/Y buttons on the front panel while in the block's edit mode
• Assign a switch assigned to the effect's X/Y MIDI CC
• MIDI
• Software editor

Bypass mode

When the Axe-Fx II is put into Bypass, the signal is routed directly to the D/A converters after A/D conversion. Inbetween there's no signal processing. It's like a row of just shunts on the grid. There's still signal but it is less loud and will sound "dry". Bypass mode is indicated on-screen. So if your sound suddenly is gone, there's no amp distortion to be heard and no effects, always check the Bypass button.

In Bypass mode the signal from Input 1 is sent to all outputs, regardless of the I/O settings.

There's a 6 dB volume level difference between Bypass and non-Bypass mode. This is by design.

The MIDI CC for putting the Axe-Fx into Bypass mode is CC 13.

Comparing the Axe-Fx III to the Axe-Fx II

Dimensions

• The III is taller, at 3U instead of 2U, but shallower, at 11.5” deep instead of 12.9”

I/O:

• The III has 4 independent stereo outputs, instead of 2, plus auto-switching front/rear instrument inputs (with "Secret Sauce IV" on the front input) and 3 stereo inputs. INs and OUTs can be used in the usual ways, or paired to insert outboard gear in up to 3 stereo loops
• The red Output LEDs in the front panel meter bridge now light at -1 dBFS, and a warning pops up when the input is clipping
• Inputs 2, 3 and 4 support guitar impedance
• The nominal level of Outputs 1 and 2 can be switched between -10 and +4 dB
• The III has adjustable input levels for USB, AES and SPDIF

IMPORTANT: the Axe-Fx III's default output level is -10 dB (lower than the II: +4 dB)

User interface

• Instead of a RECALL screen, the III has a HOME button. The new Home menu provides access to Presets, Meters, with soft-button access to the Tuner, layout grid, controllers, and Setup menu
• The III's Home Screen also has Performance Pages, allowing fast access to often-used and critical controls
• Instead of a LAYOUT button, the layout grid is accessed from a soft-button in the Home menu, or by pressing ENTER, or pressing VALUE while on the Home page. The grid has new features like Zoom, CPU meter, and a "mini" tuner
• You can use old familiar workflows with the NAV buttons and VALUE wheel, but you’ll move much faster through editing if you use the five Push-knobs under the display
• The hardware and editor now optionally prompt before changing presets if the current preset has been edited or scenes has been switched . This prevents users from losing edits

Sound

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[38] The Axe-Fx III has slightly more high end extension than the previous products. It's more accurate.

Effects

• New blocks include: Plex Delay, Ten-Tap Delay, Multitap Delay, Multiplexer, Realtime Analyzer, Scene MIDI block, IR Player, Dynamic Distortion
• Authentic Tri-Chorus type in the Chorus block
• 4 instances of Drive
• 4 instances of Delay
• 2 instances of Send/Return
• Pitch block: 4 voices. Pitch block has its own (faster) pitch detector. Latency and stability has been improved. New Virtual Capo mode
• Much improved Reverbs, Pitch shiftching
• Looper: more looping time, better control
• Tone Matching in UltraRes, no difference between Offline and Live modes
• Tuner: improved tracking, works on any (or: all 4) input
• Compressor: "RMS" is the same as "Fast RMS" in the AX8 and Axe-Fx II. "E-L Panel" mode added. Filter parameter has been replaced with EQ-ing tools. More compressor types, sustainers added
• Drive blocks: much improved. Higher oversampling ratio and double-precision filters in some places. GEQ added. Authentic controls. FASPICE technology
• Gate: improved
• The output level of some effects / effects types has been changed, such as Resonator and Studio Compressor
• Vocoder now has 24 bands
• Some effects have their own envelope follower, such as Plex Delay
• Improved noise gate in the Input block, now also includes EMI filtering
• Stereoizer mode in Enhancer block
• Improved Multiband Compressor
• Wah has an GEQ
• Multi Delay expansion
• Auto Swell mode in Volume block
• Bias and Harmonic Tremolo types
• More Compressor types
• Plex Reverb

Modifiers and controllers

• The Controllers block now has 4 channels, so the Envelope Controller can have 4 different settings per preset, for example
• 4 Scene controllers instead of 2
• Damping (modifier menu) is replaced with Attack/Release parameters
• To control the bypass state of a block using a modifier, you no longer modify the Bypass Mode parameter, but a dedicated Bypass parameter
• A modifier can now be attached to either a single channel of an effect block, or to all its channels. You can't use a different modifier on a single parameter per channel

Presets, scenes, blocks and channels

• 14x6 grid instead of 12x4
• Axe-Fx III Mark I: 512 preset slots instead of 768. The number of presets in the Mark II and Turbo models has been increased to 1024
• More CPU available per preset
• Inputs and Outputs must be placed on the grid as blocks
• Each Scene has its own customizable name
• Up to 4 Channels per block (Multiplexer: 6)
• Presets either default to a specified scene upon loading, or to the scene that was active when the preset was saved (global option)
• 8 Global Blocks per effect block instance. Some blocks (like Multiplexer) do not support Global Blocks
• Switching scenes is much faster
• Faster engage/bypass speed for some blocks
• Songs and setlists
• Scene ignore feature

Amp modeling

• Additional amp models
• "Ares" amp modeling, "Cygnus" and "Cygnus X-2" amp modeling
• “Character” and "Pick Attack" parameters are gone
• Pre-EQ controls have been added
• "Boost types" have been integrated into the Amp block. These act as clean boosts replicating the oft-used “Drive on 0, adjust Level as desired” boost technique. This allows boosting the Amp block without requiring a separate Drive block. The "Boost Level" parameter controls the amount of boost
• Output Mode lets you switch between FRFR and SS Power Amp + Cab
• New Speaker Compliance parameter controls nonlinear behavior of the virtual speaker
• New impedance modeling and impedance curves
• Auto impedance curve selection (part of DynaCab)
• FASPICE technology
• Authentic controls
• Oversampling Mode

Cab modeling

• Mixes up to 4 different IRs at once
• Output level is automatically normalized
• Mic Modeling has been removed, "Proximity" remains
• Speaker Size parameter is gone
• There are now Factory 1, Factory 2, User 1 and User 2 banks, each with 1,024 IRs, and a Legacy bank containing all 189 IRs from the Axe-Fx II, and 16 Scratchpads
• Two "IR Player" blocks
• Different Slope settings for Hi Cut and Low Cut
• Improved room ambience, with floor reflections
• IR alignment
• Support for FullRes IRs
• DynaCabs allow control over position and distance and provide new IRs

Editors, foot controllers

• FC foot controllers. Configuration on hardware or editor
• Editor software and foot controllers share control, updating each other seamlessly without re-sync issues or paused communications
• FASLINK II (XLR-to-XLR) connects the Axe-Fx III to the new FC controller(s)
• The editor supports hi-res displays

MIDI

• Up to 8 MIDI PCs or CCs can be transmitted upon scene changes
• A MIDI PC can be transmitted upon preset changes
• A MIDI PC can be sent through the MIDI OUT port upon preset changes
• The FC can send additional MIDI commands through Control Switches (similar to those on the FX8 and AX8)
• The Bypass state of an effect can simply be toggled (no need to specify "0" or "128" when sending a MIDI CC), which is useful with MIDI controllers that don't send values along with MIDI CCs

Computer

• No driver required for Mac computers
• 8x8 USB Audio interface
• Faster MIDI-over-USB
• USB communications do not increase CPU load anymore

Powering on

• When powering on, the unit reads all user cabs. This happens in the background
• The III shows diagnostics

What's gone:

• The MFC-101's "Axe-Fx Mode" is no longer supported
• X/Y switching (replaced with Channels)
• X/Y Quick Jump (soft knob on the Home page lets you jump to the Amp block)
• Swapping presets on hardware (requires editor)
• Certain hardware buttons like Effect Bypass (replaced with soft knobs)
• Recall Effect function
• Quad Chorus block (now available in the Multitap Delay block)
• FX Loop block (replaced with Output blocks)
• Cab block parameters: Mic modeling, Motor Drive, Speaker Size
• Amp block parameters: Character, Pick Attack
• MIDI phantom power
• USB Adapter Mode

Effects:

List of effects in each device

The Axe-Fx II and Axe-Fx III cannot share presets electronically. You can trying using FracTool to import Axe-Fx II presets into the Axe-Fx III, however be aware that the parameter settings might not transfer correctly.

FRACTAL AUDIO QUOTES

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[39] III is a little punchier. I really notice it when I A/B between the III and II (or the AX-8). If you plug into one and then plug into the other it's not as noticeable but if you use an A/B switch it's a more marked difference.

[40] Everything sounds better. I think a big part of it is the quality of the I/O. The I/O measures flatter and less distortion than my $2000 interface.

[41] It actually does sound a little better. The extra DSP horsepower means that we didn't have to make compromises in some of the algorithms. The amp modeling algorithm is very similar but there's a few places on the II where we had to make compromises to get the algorithm to run within the allotted time. Also the III has a higher internal oversampling rate and a higher bit depth on some calculations (64-bit vs. 40-bit).

Better algorithms, higher upsampling, better analog I/O design.

Comparing the Axe-Fx II, AX8 and FX8

List of effects per device

Read this: Effects list

Axe-Fx II XL+ versus AX8

Comparison

Axe-Fx II XL+ 

Provides effects in a 4x12 grid, including Quantum amp/cab modeling, and extensive routing options in a 19" rack device. It features multiple outputs, an effects loop and various digital I/O. The MFC-101 foot controller is connected through FASLINK. It has all Fractal Audio effect algorithms and supports Tone Matching and IR Capture.

AX8 

An all-in-one floor version of the Axe-Fx II, designed for the gigging musician. It provides Quantum amp modeling and UltraRes speaker cab sims, plus hundreds of effects and the familiar 4x12 grid, with the same quality as the Axe-Fx II. It differs from the Axe-Fx in that it offers only one instance per preset of amp, cab, and some effects blocks (e.g. Reverb, Flanger, etc.). Also, certain esoteric effects found on the Axe-Fx are not included in the AX8 (Vocoder, Megatap, etc.) It has multiple outputs offering Humbuster technology, SPDIF out, and an effects loop.

The differences are discussed in the AX8 Owner's Manual.

FRACTAL AUDIO QUOTES

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"The XL+ front input circuit is identical to the AX-8 except the AX-8 doesn't have the variable impedance circuitry."

[42] AX8 and Axe-Fx II share the same code base so any updates to the Axe-Fx II apply to the AX8.

[43] Same grid as Axe-Fx II. 512 user cab slots, 512 preset slots. Same factory amps and cabs as Axe-Fx II. Same high-quality, low-noise design as Axe-Fx II XL+. True differential I/O to the converters, not the single-ended stuff used in consumer-grade gear. Silent Switch technology from the MFC-101 Mark III. Humbuster I/Os. Most importantly it has Quantum and the Fractal Sound".

[44] Layout grid is just like the Axe-Fx II.

[45] The AX-8 is not an Axe-Fx II on the floor. If it was it would cost a heck of a lot more than it does. It uses the exact same modeling code as the Axe-Fx II. The overwhelming majority of people love the AX-8 and understand its place in the Fractal Audio model line-up. Putting an Axe-Fx II on the floor wasn't feasible due to the DSPs used in the Axe-Fx II requiring active cooling and being very expensive. The AX-8 was designed as a lower cost, simpler product that would address the needs of 99% of users. Power users will want an Axe-Fx II which is still the best modeler in the world.

[46] The SHARC processors in the AX-8 support 40-bit word lengths and we use them just as we do in the Axe-Fx II.

[47] The AX8 uses the same converters as the Axe-Fx II. We put the money where people can't see it but where they can hear it.

[48] The Axe-Fx II can run multiple instances of amps, cabs and most effects. The AX8 cannot. The processors used in the AX8 are not nearly as powerful as the processors used in the Axe-Fx II. They are also significantly less expensive.

[49] It does not have the vocoder and several of the other more esoteric effects. It does have the looper, synth and all the bread-and-butter effects. And it has the beautiful high-quality reverb from the Axe-Fx and FX8 (because I'm a reverb junkie). Most importantly, though, it sounds like an Axe-Fx.

[50] They are very cool. They're not an Axe-Fx but they're close. Same amp and cab modeling. Stripped down effects section. Two 450 MHz DSPs; one for amp modeling the other for effects/housekeeping. Uses the same silent switch technology as the MFC-101 Mark III and FX8. Switches are assignable per patch via our new "Switch Assign Matrix" feature.

[51] It's pretty much "Axe-Fx Lite". All the advanced parameters are available in the amp block, you access them via the traditional edit menu. The dedicated Bass, Mid, etc. knobs can be accessed at any time. And it sounds like an Axe-Fx, so there's that.

[52] The AX8 was not designed for use with Global Block.

Hardware

DSP

• Axe-FX II: two TigerSHARC DSPs
• AX8: two dual-core 450 MHz ADSP-21469s DSPs and two microcontrollers
• The devices use the same converters and op-amps

Housing

• Axe-Fx II: 19" rack device
• AX8: floor device

Expression pedals and switches

• Axe-Fx II XL+: two PEDAL inputs
• AX8: four connections for expression pedals and switches

Analog I/O

• Axe-Fx II: front and rear Input 1
• AX8: front Input 1 only
• More information about the AX8's I/O

Digital I/O

• Axe-Fx II: USB audio, SPDIF, AES
• AX8: only SPDIF out

Hardware interface

• Axe-Fx II: for remote switching you need a separate foot controller such as the MFC-101. No dedicated physical amp controls (menu only)
• AX8: 8 numbered assignable switches and 3 assignable F-switches. Dedicated physical amp controls on top of the unit with LED-rings

Headphones

• Axe-Fx II: headphones output
• AX8: no headphones output

MIDI

• Axe-Fx II XL+: hardware-separated MIDI IN, OUT and THRU connections. MIDI can be used for editing
• AX8: MIDI IN and shared MIDI OUT/THRU connections. MIDI can't be used for editing

USB

• Axe-Fx II: no USB host, needs driver on computer for editing and data transfers
• AX8: USB host, no driver needed

Effects and parameters

Axe-Fx II

• Full set of all effect algorithms. Many of the effects are available in more than one instance (two Amp blocks etc.). Compared to the AX8 (and FX8), there are a few differences in X/Y switching
• Global Blocks
• Adjustable Input Impedance
• Tremolo in the Amp block
• Room ambience, De-Phase, mic modeling, Motor Drive and channel strip modeling in the Cab block
• Tone Matching
• IR Capture

AX8

• Selection of the effect algorithms (listed here). Compared to the Axe-Fx II there are a few differences in blocks supporting X/Y switching. There is one instance available of each effect, for example a single Compressor block, Amp, Cab, Pitch etc, with some exceptions. All "types" within a specific effect (all amp models, all compressor types etc.) are included
• Less CPU power. It'll disable blocks automatically when the CPU usage (preset size) gets too high
• MORE Looper time than the Axe-Fx II
• No Global Blocks, no adjustable Input Impedance, no Tremolo in the Amp block, no Room ambience / De-Phase / mic modeling / Motor Drive / channel strip modeling in the Cab block, no Tone Matching, no IR Capture

User interface

Axe-Fx II

• Boots to the RECALL screen
• Press LAYOUT to see the grid
• There are four NAV buttons, PAGE buttons, ENTER and EXIT and a dedicated VALUE knob to navigate
• Dedicated X/Y buttons

AX8

• Boots to the FS (Footswitch) Page
• Instead of a LAYOUT button, the grid is accessed as the second page of the main menu. When on the grid, press EXIT to return to the Footswitch page
• Instead of NAV buttons, you will primarily use the E/NAV knob to get around menu pages. Instead of a VALUE knob you’ll use A,B,C,D, and E knobs.
• Instead of dedicated X/Y buttons, you’ll press and hold a footswitch to toggle X/Y for an effect, or if no footswitch is assigned, select or edit the effect and double-tap EDIT

Editing shortcuts are different because of the hardware design.

Grid, presets and scenes

The AX8 and Axe-Fx II both support the 4x12 grid and scene switching. The AX8 lets you specify the default scene which is loaded after switching presets.

The Axe-Fx II and AX8 cannot share presets. But you can transfer individual block settings from one product to another using the software editors. It's also possible to convert presets with 3rd-party software: FracTool.

The AX8 doesn't provide the Mixer block and Send/Return blocks.

When using the FXL block to create an AUX output, the FXL block must be placed in parallel rather than series. (Unlike the Axe-Fx II, the AX8 does not detect when a plug has been inserted into INPUT 2.)

AX8 versus FX8

Differences

FX8 – provides effects for the gigging musician who uses his own amp(s) and cabinet(s), including specific "no tone suck" support for 4CM (Four Cable Method). It provides dedicated relays for amp channel switching and other amp functions.

AX8 – provides effects, including amp/cab modeling, for the gigging musician who doesn't use a traditional amplifier. It has multiple outputs, SPDIF out and an effects loop.

Differences:

• The interfaces (knobs and buttons, I/O, preset layout) are different which makes operation and navigation different. The AX8 provides physical amp controls.
• The AX8 uses a 4x12 layout grid, the FX8 doesn't. This means that series or parallel routing of effects is also different.
• The AX8 uses a flexible architecture that does NOT designate separate PRE and POST chains. It is still possible to use a 4CM hookup, but this needs to be set up manually in each preset using the FX Loop block to insert the preamp.
• Unlike the FX8, the AX8 is NOT specifically designed for Read this: unity gain, but when you’re using it “direct” this really should not be a concern.
• The effects in both devices mostly the same with a few differences. See: Effects list
• The AX8 has no RELAYS to switch other gear. Instead, it has four jacks for external switches or pedals.
• The AX8 has a SPDIF digital output.
• The FX8 has a global looper. The AX8 Looper is not “global”, meaning it needs to be inserted as a block on the grid for every preset where you want to use the Looper.
• The FX8 and AX8 cannot share presets, but you can transfer individual block settings from one product to another using Fractal Audio's editors.
• The numbering of switches on the AX8 and original FX8 is different. The layout of the switches on the FX8 Mk II is the same as on the AX8.
• The FX8 has additional MIDI blocks. The AX8 has additional Control Switch blocks.
• The FX8 supports True Bypass, the AX8 does not.

Fractal Audio comments

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[53] FX8 works very well in the FX LOOP of the AX8.

[54] The AX-8 is not "way more powerful" than the FX-8. No one from the company ever said that. The AX-8 has one additional DSP that is DEDICATED to amp modeling. If you don't use the amp modeling the AX-8 has the same power as the FX-8.

As we stated recently we are working on a firmware release for the FX-8.

The AX-8 will not work as well as the FX-8 in 4CM. It is not designed for that. It will do 4CM, as will most digital processors but the FX-8 is the only processor of which I'm aware that is truly optimized for 4CM. That optimization requires a lot of expensive circuitry. The op-amps used are very expensive and there's dozens of them just to support the 4CM stuff. Add to that relays for true bypass, metal film capacitors, etc., etc., and you end up with an expensive design.

The FX-8 and AX-8 are built on the same code base. There is a single folder that is used to build the common elements for both products. Enhancements to one automatically enhance the other. All this work we've been doing for the AX-8 will improve the FX-8.

The AX-8 will be much more popular than the FX-8. That should be obvious. Most people want the amp modeling. If you don't care about the amp modeling then the FX-8 is the better product and the whole reason for having two different products.

[55] The AX8 and FX-8 uses the same converters (CS4272-CZZ) and op-amps. The circuit design in the FX-8 is necessarily much more complex to support true-bypass switching (without pops and clicks) and to optimize the outputs for use in 4CM.

The AX8 removes the dedicated true bypass switching circuitry and simplifies the output design to save money. The cost savings is used towards an extra DSP.

[56] The XL+ does not offer True Bypass, nor does it offer additional relay outputs for amp channel switching. The FX8 has additional circuitry optimized for 4CM. The True Bypass can be applied to the Pre stage, Post stage, or Both. Giving more flexibility when using 4CM.

[57] Dimensions and weight are the same as the FX8.

[58] The AX8 has Humbuster outputs as well. It will do 4CM but probably not as good as an FX8 which was purpose-designed for 4CM. If we used the output topology of the FX8 in the AX8 the AX8 would cost a LOT more.

Tips and tricks

Racking the Axe-Fx II

The Axe-Fx II is a 19” 2U device. It can be mounted in a rack or rackbag. If necessary combined with a racked power amp, a power conditioner, a custom front panel, a 3rd party controller, etc. Rear rack rails are not required or supported. It's about two inches deeper than the Standard and Ultra.

The rack ears at the front are removable.

You can put the rack or bag on a amp stand, such as this example.

FRACTAL AUDIO QUOTES

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[59] The handles are structural. You can remove them but I recommend replacing them with a bolt and nut.

From the rack ears to the back of the chassis is only 13. You should allot a couple inches for plugs and cables though.