Mesa/Boogie Walk About Bass Amplifier owner manual Harmony as it is dialed for either cut or boost

FOUR - STAGE VACUUM TUBE PREAMPLIFIER

ACTIVE

INSTRUMENT

INPUTS

PASSIVE

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.

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FRONT PANEL CONTROLS:

GAIN BASS MID

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.

TREBLE DI LEVEL MASTER

ON

POWER

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.

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