
INPUT DRIVE (was DRIVE) – In a typical amp this is called various names (Drive,
Volume, Gain, etc). It is the knob closest to the input jack. In many cases it has a
bright cap so the frequency response will be dependent on the knob position.
As the gain increases the tone shifts from a treble and upper mid emphasis to a
bass and lower mid emphasis.
OVERDRIVE – A second drive control for some amp models. It does not have a
bright cap so it only aects the gain. Set Overdrive to 8.00 to get the identical
response to pre-v10.10 rmware for models that have Overdrive.
INPUT TRIM – A clean, linear gain applied at the input to the amp block that
adjusts the relative gain of the preamp. (This is analogous to changing the type
of tube for V1 in an actual amp.) It does the same thing as the BOOST switch,
the dierence being that you can control how much is boosted or cut (+/-20
dB). As a rule of thumb, every 2x multiplier equals +6dB boost. In other words,
Input Trim at 4.0 produces a +12dB boost. Input Trim should be set to 1.00 if
you want to match the actual amp.
BOOST – Toggles the input boost for an additional 12 dB of input gain. Enabling
Boost sometimes works better than turning up preamp gain.
CUT – Reduces the amount of low frequencies into the amp. This can be used
to achieve a tighter tone or to reduce low-end“ub”. This is similar to increasing
LOW CUT (Tone page) while still retaining some low end so it doesn’t get thin.
Provides an easy way to cut the overpowering bass in models such as Recto,
Splawn Nitro, Komet and others.
FAT – Emphasizes midrange“body” by shifting down the tonestack center
frequency. Specically, it alters the tonestack treble capacitor, so the eect
depends on the tonestack’s location (see TONE page).
BRIGHT – A“treble peaker”which functions mainly to compensate for the loss
of highs at low amp volume. The eect may be subtle or quite pronounced,
depending on the amp selected, and it is also aected by the BRIGHT CAP.
SATURATION – Switches in a zener diode clipping stage between the preamp
and the tone stack (the“Arrendondo Mod”) for more aggressive distortion char-
acter which also adds compression and cuts volume. You may have to adjust
the MASTER or LEVEL to compensate.
DYNAMIC PRESENCE – Models the output transformer leakage inductance that
results in a brightening of the tone when the power amp is pushed. Increasing
this value results in a brighter response as the virtual power amp is pushed.
When playing softly or at lower gains, the inuence of this control is lessened.
Note that this only aects the power amp modeling and is dependent on
the degree of power amp overdrive. This control can also be set negative to
cause the tone to darken when playing hard. This control can also be used to
help“dial in”the sweet spot of an amp model. As the MV is increased an amp
becomes more liquid, compressed and easier to play. However, the highs may
get overly compressed causing the amp to sound too dark. The Dynamic Pres-
ence control allows you to get the desired power amp drive and liquid feeling
and then bring the highs back without aecting the rest of the spectrum.
DYNAMIC DEPTH – Analogous to the Dynamic Presence control, this increases
or decreases low frequencies when the virtual amp is being pushed. While real
amps don’t display this behavior, it is a valuable tone-shaping tool.
MASTER VOL TRIM – Can be used to increase (or decrease) the Master Volume
for non-MV amps. If MV is 10 and you set MV Trim to 2.0 then the MV will be 20.
Amp Block
You can also adjust preamp gain globally with GLOBAL AMP GAIN, which
aects every amp and preset. One reason you might do this is to compensate
for the gain dierence when switching to a hotter/quieter guitar.
On the Axe-Fx unit: GLOBAL button > CONFIG > AMP GAIN
Before adjusting the MASTER VOL, be aware that it defaults to 10 for non-
master volume (vintage) amps. If you want more MV on non-MV amps,
increases the MV TRIM.
In most cases, DRIVE, BASS, MID, and TREB are accurate within 10% of the
actual amp.
For most tone stacks, when you set the BASS and TREB to zero, the tone stack
becomes basically“at” and the MID becomes a volume control.
INPUT DRIVE and OVERDRIVE will have a dramatic eect on the response of
the amplier and the personality of your instrument.
See the footnote in the amp description list to quickly nd the amps that
have the OVERDRIVE control.
TOP ROW BOTTOM ROW
COMP – Controls the amount of preamp compression and sets the compression
threshold of the cathode follower. Same as the CATHODE THRESHOLD param-
eter, which is one of three settings that adjust the cathode follower algorithm.
See the Dynamics page for more. Many models default to zero as they do not
have measureable compression.
PRESENCE – Boosts/cuts upper frequencies from the power amp by varying
negative feedback frequency response. Increased presence can help sound cut
through a heavy mix. Decrease it to compensate for overly-bright amps. Pres-
ence is tightly coupled to speaker impedance (HI FREQ, HI RESONANCE).
HI CUT – On amps with no negative feedback (DAMPING=0), PRESENCE is
replaced with HI CUT, a simple high-shelf EQ at the power amp output.
DEPTH – Boosts low frequencies from the power amp by varying the negative
feedback frequency response. On amps with a xed depth circuit, Depth will
have a preset value. Also called“Resonance”or“Girth”on some amps.
MASTER VOL – Determines the amount of power amp distortion. As it increases,
the tone controls have less inuence on the sound. Amp models default to a
starting Master Volume setting when selected. (Non-MV amps default to 10.)
BASS/MID/TREB –“Passive” tone stack. Can be changed with TONESTACK TYPE.