Axe-Fx Firmware Version 21.00

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Prince said:
“The default values of various parameters have been updated. Existing presets are automatically updated to the new values upon load.”

Could you please expound upon this? Is it a) default values of X parameter has changed in all amps? Or b) default values of X parameter has changed on amps #1,2,3,etc.

If there were universal changes of a specific parameter(s), any chance we can get a list of what those are? Thank you!
Click to expand...
On top of my Head, Bias Excusion, Negative Feedback, Low cut in preamp, Cathode Follower, there might be more.

"All amp models have been updated as a result of the aforementioned improvements."
 
Yet another “it can never get better than this” release. Been getting them for many years.
Thanks Cliff & team.
What a remarkable product!

Pauly

FractalAudio said:
https://www.fractalaudio.com/downloads/firmware-presets/axe-fx-3/21p0/axefxiii_dsp_rel_21p00.zip

NOTE: You MUST perform a Refresh After Firmware Update if using Axe-Edit and you were using one of the 21.00 betas prior to this!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Axe-Fx III Firmware Release Notes​


21.00

New “Cygnus X-2” amp modeling:

  • Improved Amp block output transformer algorithm. New algorithm more accurately models B-H curve resulting in a clearer low end. New algorithm now also accounts for effect of speaker impedance on transformer response.
  • Improved power tube modeling. This yields better dynamics, improved low frequency accuracy and more accurate interaction with output transformer.
  • Improved cathode follower algorithm. Provides more accurate “cleanup” when volume is rolled off.
  • Improved triode algorithm more accurately models plate bypass capacitors.
  • Improved dynamic frequency response accuracy. This yields more “crunch” and less “fizz” with high gain tones, especially for detuned styles.
  • Various other improvements.
  • All amp models have been updated as a result of the aforementioned improvements.
The default values of various parameters have been updated. Existing presets are automatically updated to the new values upon load.

Improved Drive block modeling to more accurately model effects of op-amp finite open-loop gain and GBW product.

Added “Griddle Cake” Drive model based on a Crowther Hot Cake. The “XLF” switch on the pedal can be replicated by turning the Bass Response knob fully CW.

Added “Overdrive Volume” parameter to Dumble-type amp models (ODS-100, Two Stone, etc.). This is sometimes labeled “Ratio” or “Lead Master”. As the Master Volume on these amps often has a bright capacitor the Overdrive Volume control allows setting the Master Volume higher to counteract the bright cap and then lowering the power amp drive with the Volume.

Added “Plate Suppressor Diodes” parameter. This value is set automatically when the amp model is chosen but the user can override the default setting. Most amps do not have suppressor diodes but some do (e.g., Trainwreck Express). These diodes (also called “snubber” or “flyback” diodes) prevent undershoot on the power tube plates due to inductive kick and reduce upper harmonics thereby reducing “fizz”.

The Ideal amp controls have been updated.

Added Brit Studio 20 Amp model based on a Marshall SV20H.

Added Plexi 50W 6CA7 Jumped Amp model. This is simply the jumped version of the Plexi 50W 6CA7.

Added features to the IR Capture Utility. The manual will be updated with the relevant information.

Renamed USA Clean to USA Rhythm 1 to be more in line with actual amp.

Reduced CPU usage in some cases.

Changed tone stack tapers for Class-A 30W TB to vintage specs.

Fixed wrong capacitor value in USA JP IIC+ models when Presence Shift is off.

Fixed wrong coupling capacitor value in 1959SLP Treble, 1959SLP Jumped and 1987x Treble amp models.

Fixed wrong resistor value in tone stack of Solo 88 Rhythm and Lead models. Probably not audible though.

Fixed low frequency behavior of Recto2 models due to loss of precision.

Fixed wrong treble pot taper in CA3+ models.

Fixed wrong capacitor value in Friedman HBE V1 Fat model.

Fixed wrong resistor value in AC-20 12AX7 models.

Fixed wrong Depth knob taper in Archean models.

Fixed wrong capacitor value and wrong feedback network connection in Energyball model.

Fixed missing resistor in Euro Uber tone stack.

Fixed High Mid control in Drive block set to minimum when importing presets created prior to 19.01.

Various other fixes and improvements.
Click to expand...
 
FractalAudio said:
https://www.fractalaudio.com/downloads/firmware-presets/axe-fx-3/21p0/axefxiii_dsp_rel_21p00.zip

NOTE: You MUST perform a Refresh After Firmware Update if using Axe-Edit and you were using one of the 21.00 betas prior to this!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Axe-Fx III Firmware Release Notes​


21.00

New “Cygnus X-2” amp modeling:

  • Improved Amp block output transformer algorithm. New algorithm more accurately models B-H curve resulting in a clearer low end. New algorithm now also accounts for effect of speaker impedance on transformer response.
  • Improved power tube modeling. This yields better dynamics, improved low frequency accuracy and more accurate interaction with output transformer.
  • Improved cathode follower algorithm. Provides more accurate “cleanup” when volume is rolled off.
  • Improved triode algorithm more accurately models plate bypass capacitors.
  • Improved dynamic frequency response accuracy. This yields more “crunch” and less “fizz” with high gain tones, especially for detuned styles.
  • Various other improvements.
  • All amp models have been updated as a result of the aforementioned improvements.
The default values of various parameters have been updated. Existing presets are automatically updated to the new values upon load.

Improved Drive block modeling to more accurately model effects of op-amp finite open-loop gain and GBW product.

Added “Griddle Cake” Drive model based on a Crowther Hot Cake. The “XLF” switch on the pedal can be replicated by turning the Bass Response knob fully CW.

Added “Overdrive Volume” parameter to Dumble-type amp models (ODS-100, Two Stone, etc.). This is sometimes labeled “Ratio” or “Lead Master”. As the Master Volume on these amps often has a bright capacitor the Overdrive Volume control allows setting the Master Volume higher to counteract the bright cap and then lowering the power amp drive with the Volume.

Added “Plate Suppressor Diodes” parameter. This value is set automatically when the amp model is chosen but the user can override the default setting. Most amps do not have suppressor diodes but some do (e.g., Trainwreck Express). These diodes (also called “snubber” or “flyback” diodes) prevent undershoot on the power tube plates due to inductive kick and reduce upper harmonics thereby reducing “fizz”.

The Ideal amp controls have been updated.

Added Brit Studio 20 Amp model based on a Marshall SV20H.

Added Plexi 50W 6CA7 Jumped Amp model. This is simply the jumped version of the Plexi 50W 6CA7.

Added features to the IR Capture Utility. The manual will be updated with the relevant information.

Renamed USA Clean to USA Rhythm 1 to be more in line with actual amp.

Reduced CPU usage in some cases.

Changed tone stack tapers for Class-A 30W TB to vintage specs.

Fixed wrong capacitor value in USA JP IIC+ models when Presence Shift is off.

Fixed wrong coupling capacitor value in 1959SLP Treble, 1959SLP Jumped and 1987x Treble amp models.

Fixed wrong resistor value in tone stack of Solo 88 Rhythm and Lead models. Probably not audible though.

Fixed low frequency behavior of Recto2 models due to loss of precision.

Fixed wrong treble pot taper in CA3+ models.

Fixed wrong capacitor value in Friedman HBE V1 Fat model.

Fixed wrong resistor value in AC-20 12AX7 models.

Fixed wrong Depth knob taper in Archean models.

Fixed wrong capacitor value and wrong feedback network connection in Energyball model.

Fixed missing resistor in Euro Uber tone stack.

Fixed High Mid control in Drive block set to minimum when importing presets created prior to 19.01.

Various other fixes and improvements.
Click to expand...
Thank Cliff and team, always looking out for the customer !
Cheers !
 
Question for @FractalAudio.

Prior to v21, were Plate Suppressor Diodes not modeled at all? Or were they modeled on amps that had them and not on others, and neither of those could be changed?

In other words, is this a new facet of amp behavior that's now being modeled, or new control of existing modeling?

In either case, Awesome! You're a serious treasure Cliff!
 
Dave Merrill said:
Question for @FractalAudio.

Prior to v21, were Plate Suppressor Diodes not modeled at all? Or were they modeled on amps that had them and not on others, and neither of those could be changed?

In other words, is this a new facet of amp behavior that's now being modeled, or new control of existing modeling?

In either case, Awesome! You're a serious treasure Cliff!
Click to expand...

Dunno if you saw this, but it might help answer the question:
FractalAudio said:
The new "Cygnus X-2" amp modeling introduced a new parameter called "Plate Suppressor Diodes". Plate suppressor diodes, also known as "snubber" or "flyback" diodes are diodes connected between the power tube plates and ground.

The purpose of these diodes is to clamp the inductive "kick" caused by the reactive load seen by the plates. A speaker is a reactive load and has a positive reactive component at high frequencies. This means it looks inductive. Inductors resist change in current. When the plate voltage drops rapidly to zero the inductance of the load causes the voltage to undershoot.

A suppressor diode clamps the voltage and prevents undershoot. This does two things:
1. It prevents excessive voltage at the plates and transformer primary. This protects the transformer from damage due to dielectric breakdown.
2. It also reduces "fizz". The undershoot manifests as increased high frequency content in the range where the load is inductive, typically from 1kHz and up.

Most amps don't have flyback diodes but there are a handful of notable exceptions: Trainwreck Express, Fender Blues Jr., Peavey 5150, and several others.

Flyback diodes were originally added to amps to protect the output transformer but most, if not all, techs don't realize that they also change the clipping behavior.

Consider the graph below:

View attachment 110516

The blue trace is a plot of a tube power amp output with no flyback diodes. The green trace is the same power amp with flyback diodes. Those spikes in the voltage are what can damage a transformer and also what cause "fizz".

In a real tube amp these diodes are under intense stress and may fail. In our virtual world these diodes are indestructible.

So if you like your tones as fizz-free as possible experiment with the Plate Suppressor Diodes parameter. Note that turning them on will reduce the "chime" at edge-of-breakup and may not be suitable for vintage tones.
Click to expand...
 
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