Doc Q7.0
41
apply circuit values suited to an amp of that general type. If the amp has a hard-wired treble peaker, the
default
BRIGHT
state is ON.
To turn the Bright, Fat, or Cut switches ON or OFF, use the
keys to select the knob above them and
press
. The label beneath the knob will fill to indicate that the circuit is engaged.
BRIGHT switch ON
BRIGHT switch OFF
BRIGHT (knob)
–
This is a high treble filter between the preamp and power amp, useful to darken or
brighten the tone in a unique way. This control accurately replicates the “Presence” control on the original
version of the “USA Pre” type amps. (Not to be confused with the “
BRIGHT SWITCH”
(see below) which
engages/disengages a capacitor across the drive pot.
Amp Power Amp Page (“PWR”)
5.1.3
PRESENCE/HI-CUT
– The Presence control boosts (or cuts) the upper frequencies from the power amp
simulator by varying the negative feedback frequency response. Increased presence can help a sound cut
through a heavy mix.
Amps with no negative feedback circuits in their design cannot utilize a presence circuit. Therefore, for amp
types of this type (or for any type if you manually set
NEGATIVE FDBK
to 0.00) the PRESENCE control is
replaced with the “HI-CUT” control. This high-frequency filter allows you to control the tone the power amp.
When changing to a model with no negative feedback (i.e. Class-A, Mr.Z, Recto Red), be sure to check your
presence settings as settings higher than zero may darken the sound undesirably.
When certain “USA” amp models are used, a
PRESENCE SHIFT
switch appears beneath the Presence knob. This
replicates the behavior when the Presence knob is pulled out on these amps. Note that the behavior of this
switch is authentic and may result in volume reduction when active since the negative feedback is increased
which lowers the loop gain.
DEPTH
– Boosts low frequencies from the power amp simulation by varying the negative feedback frequency
response. The
DEPTH
control is set by default to an appropriate value when the amp
TYPE
is selected, but this
setting may be overridden.
TUBE TYPE
– The virtual power amp in the Axe-Fx includes modeling of the plate impedance of the power
tubes. Plate characteristics are adjustable via
DYNAMIC DAMPING
, an advanced parameter. The
TUBE TYPE
parameter sets
DYNAMIC DAMPING
automatically for you, allowing you to select from common power tube
types instead of selecting a number. EL34, EL84, 6L6, 6V6, KT66, KT88, 6550, 6973, 6AQ5 and 300B (triode) are
offered, as well as an ideal tetrode and ideal pentode. The power tube type defaults to the appropriate type
when the amp type is selected but may be changed freely.
