A part of what Cygnus did was make the Bias Excursion algorithm more accurate. And since it's now more accurate, high values now sound better/more realistic. Cliff had the Bias Excursion values turned lower before because it sounded better, but they can get turned up to where they should be now. So the setting you're seeing is just that, a setting. But the reason it's higher is because the underlying algorithm was improved which allows it to sound good at that higher setting. Among other things that were improved under the hood too I'm sure.
In the beta for 3, some improved bias algorithms were added (an early slice of Cygnus). They then decided to leave those changes out for the full release, and wait for the full cygnus release to add them back in. So the updated settings that were first previewed in that beta are now in this beta.
Shortly before actually, the bias stuff was an early sliver of cygnus that was ported I believe, but later removed until all of cygnus was ready.
Not just because it's a beta firmware. Because it updates the default values of advanced properties in the amp block. They don't want to blindly overwrite your settings in case you went into the advanced pages and made changes yourself, so resetting an amp block is a way to get that amp back to the proper default values which is usually the easier place to start re-tweaking from.
Any old XLR to 1/4" will do.
Nope, each preset and channel are independant. Resetting the amp block just resets where all the knobs are (because the setting of several of the advanced knobs have changed). So because each preset and channel saves it's own copies of the settings, they each should be reset if they don't sound right.
It's using the updated drive block that came to the Axe just before cygnus (which is the updated amp modelling), and is the drive block algorithm used in the newest Axe FX III firmwares too. resetting is probably not necessary because there aren't new default values for advanced parameters in the drive blocks, but if one sounds weird in an existing preset a reset might help.
This is actually undoing the reset because you're resetting all the knob positions with the reset, then setting them all back where they started by pasteing the old settings back.
Note that the behaviour in your note varies depending if you're set to IDEAL or AUTHENTIC for your default amp controls.
That does defeat the process of resetting the block. The reset isn't magic, it just changes the knobs to their default values on all the different params screens on the amp block. Pasting back over would just "un-reset" them. The issue is advanced settings like bias excursion, transformer drive, etc have changed with cygnus and if you don't reset you're going to be using weird values on the advanced params page, similar to if you went diving deep into the advanced menus and started tweaking stuff in there randomly and without listening as you did it.
If your preset still sounds fine, you can keep using it. But the new defaults will work better with Cygnus. One idea is to copy the settings to another preset then reset one, and you can go back and forth and compare.
Yeah, Cygnus added and updated a handful of models which are detailed a little more in the Axe FX release notes.
This is a guess by some of those drives might actually have a low cut built into their input or output and that setting is set to match it. If a drive has a built in low cut it's easier to map it to the existing control (and allow you to tweak it) than to have a hidden, untweakable low cut inside the pedal. The amp Input EQ is the same way, it defaults to the configuration of the input network of the amp it models.
I think there was a bug recently (I can't remember if on FM3 or Axe FX III) where the cathode follow compression was accidentally getting set to 69% whenever the preset was loaded with that firmware, and then if any other changes were saved that updated value was being saved again too. You could roll back to 3.03b and make a new preset then open it in 4.00b to confirm, but I suspect what's happening is those presets for saved with that bad value back in 3.xb firmware that caused the bad value to be written, and you're only noticing it now.
Matt posted the finished Cygnus preset banks for the III yesterday, so...
the FM3 just rips !!!!