3. GAIN (1 to 90 dB): Dials up the gain before the clipper stage.
Additionally, there is gain available in the Pre EQ and THETA type
distortion, so that the total amount of gain applied to the signal can
exceed 120 dB! As a point of reference, a typical amp head has a
gain of about 60 dB with the knobs set to maximum. If the GAIN is
set above 60 dB, the compressor will be disabled, even if the
PREAMP is set to CLEAN. To re-enable the compressor, the GAIN
must be lowered to 60 or less, then the COMPRESSOR parameter
can be turned from OFF to ON.
4. SAG (0 to 100): Emulates the sag of the supply voltage rails in an
amp. Higher values result in more sag. As you play harder, the
rails sag down resulting in more clipping of the signal. Play softer
and the rails move higher, resulting in a cleaner sound. This is
most effective with moderate levels of GAIN.
5. OUTPUT LEVEL (OFF to +10 dB): This is the same parameter as
in the mixer function. It is just repeated here for convenience
because as preamp parameters are changed, it is typical that the
output level will need to be readjusted.
6. COMPRESSOR (OFF or ON): Turns on the compressor, which is
positioned before the clipper stage. Compression is useful for
making clean or low gain settings sound louder, as it reduces the
level of loud passages and increases the level of soft passages.
The downside is the more compression used via lowering the
threshold, the more noise is added to the signal. See the GAIN
parameter for an explanation of how it affects the compressor.
7. COMP THRESH (-30 to 0): The lower the setting, the more the
compression.
8. PRE BASS (-15 dB to +15 dB): The level of the pre-clip bass EQ.
Generally for distorted presets this is set to 0 or negative to get a
bass cut. For higher gains, these pre-EQ sections do not so much
affect the tone of the output, but rather affect the character of the
distortion.
9.
PRE BASS (40 Hz to 240 Hz): The ‘turnover’ or upper frequency at
which the amount of pre bass boost or cut begins to lose effect.
Frequencies above this point will still be boosted or cut, just not as
much, and as frequency in the signal increases, the amount will
diminish to 0. This is a ‘shelf EQ’ type section that remains
nominally flat at low frequencies.
10. PRE MID (-15 dB to +15 dB): The level of pre-clip midrange EQ.
Generally for distorted presets this is set to a positive value to get a
boost in the mids.
See the graph on the next page for a better understanding of
the operation of a parametric equalizer.