Mesa/Boogie Walk About Bass Amplifier Stereo Amplifier User Manual


 
FRONT PANEL CONTROLS:
(Continued)
MID:
This is the only passive style control in the string of rotary tone controls. This scheme was chosen for its inherently musical
blend and for the way the passive style midrange control, with its wide spread and smooth taper,
fills in the holes
. Unlike the BASS,
this control is a
boost only,
and while it can competently remove this broad
spectrum of midrange from the mix, it cannot provide the extreme attenuation of
an active style control.
You will find, as we did, that this control works amazingly well for shaping the
midrange frequencies with a natural earthiness and character that is a perfect
counterpart to its active neighbors. It is hard to dial wrong with this more forgiv-
ing control, as it seems to give you just enough and no more. This simplicity can
be a welcome respite from the higher tech power of the adjacent tone controls...not
to mention the 3 Band SEMI-PARAMETRIC EQ For radical and specific scoop-
ing of the midrange frequencies for modern R&B and Funk styles, there is plenty
of notching power that is infinitely more accurate to be found in the 3 Band SEMI-PARAMETRIC. Because of this, we opted for the
tried and true passive style midrange control that has been working great in all of our amplifiers for decades. It’s hard to improve on
a classic.
TREBLE:
The TREBLE is also an active shelving style control like that found in the BASS and again, it was chosen for its ability
to radically shape the upper harmonic region. Like the BASS, it also has a center Q point with harmonics above and below responding
in harmony as it is dialed for either cut or boost.
As the control is increased past 12:00, it produces a 6db per octave rise in gain
starting at 723Hz until +20db is reached. From this point, gain remains constant
at +20db for all frequencies above 723Hz all the way out to 20Khz. This scheme
lends a sweetness of sound while retaining all the necessary cut and focus
associated with a traditional passive TREBLE control.
As the control is dialed below 12:00, it begins a 6db per octave cut from 3.2Khz
to the shelving point at 723Hz, where it continues to attenuate all frequencies
above 723Hz until - 20db is reached where
cut gain
remains constant until the
control reaches 7:30 (off). The ability to cut these frequencies more radically makes it possible to obtain incredibly rich and warm old-
school R&B and Jazz sounds that rival any recordings of the day.
This active shelving TREBLE control completes the rotary tone control string to create a powerful and extremely accurate network to
use as your fundamental platform. It’s no wonder many first time
WalkAbout
players make the comment that just these controls
combined with the GAIN create the best tone they have ever heard!
NOTE:
As with the BASS control, may we remind you that a control of this type with its increased power should be used with finesse.
In the TREBLE’S case, almost more so, because higher frequencies seem louder to the ear and are generally more painful when set
to extremes. Another reason to use care is that high frequencies tend to increase the ambient noise floor when set too high. This is
then exacerbated if the 3 Band SEMI-PARAMETRIC EQ is combined for added top end boost. Dial with care and music in mind.
PAGE 5
ON
POWER
TREBLE DI LEVEL MASTER
INSTRUMENT
INPUTS
PASSIVE
ACTIVE
GAIN BASS MID
FOUR - STAGE VACUUM TUBE PREAMPLIFIER