Mesa/Boogie D-180 manual Channel ONE, Master Control, Channel TWO, Tone Controls

CHANNEL ONE

The D-180 includes a two channel preamplifier with two separate input jacks and their respective gain controls, Volume 1 and Volume 2. But unlike conventional two channel pre- amps, these input channels are stacked in series so the output of Channel 1 is fed into the input of Channel 2. This enables the two channels to offer strikingly different gain and tone possibilities: Channel One is for guitar and includes incredible preamp overdrive capability; Channel Two is for bass. Adjusting Volume 1, Volume 2, and the Master offers endless combinations of sustain, overdrive, distortion and tonality--independent of playing loudness. All the great guitar tones are there--from the classic Boogie warmth and smoothness to the ultimate chunky metal crunch. So even though the D-180 has coliseum size power, it can obtain infinite sustain and a full crank sound at any volume, down to a whisper, and is easy to adjust.

MASTER CONTROL

The huge sound and versatility of the D-180 is due in part to the unique way its Master control works, and that function is the topic of one of the patents pending on D-180 technology. Ordinarily the Master is merely a volume control used to reduce gain and provide proper coupling between the preamp and power amp sections. But as part of the D- 180's Total System Integration, matching between the preamp and the power stage has been optimized and is not adjustable. The D-180 Master control works instead as a variable current limiter, thereby reducing the amplifier's power and loudnessbut not its gain. This enables the D-180 to produce unbelievable chunky crank tones -- at any volume. At a Master setting of 10 a "constant current source" maintains precise regulation of driver current in order to produce a clean, undistorted, dynamic sound that seems to be far in excess of rated power. Turning down the Master increasingly limits the current available to the driver section and creates a totally musical, symmetrical clip while reducing loudness. For power hungry guitar players lusting after a rack mount system that can sound like Joe Pass, Carlos Santana, Brad Gillis (Ozzy Osbourne) or a minor holocaust, anywhere, any time; the D-180 is it! Bass players: Remember that when the Master is set at 10, the "constant current source" takes over and maintains precise, optimum circuit calibration for you, and ultimate clean performance is assured.

CHANNEL TWO, TONE CONTROLS

Channel 2 has been especially designed for bass players. To prevent stray noise, Volume 1 should be turned to zero when Channel 2 is used and the Master must be set at 10 for full, undistorted output. Loudness is adjusted by the Volume 2 control. For introductory tone control settings, we suggest using the Bass control at 5 or 6 and the Treble and Middle controls at 6 or 7. Pull switches integrated into the controls offer useful additional tone voicings. The Pull Bright on Volume 2 operates in a frequency range above that of the Treble control and is good for accentuating string attack and upper harmonics. The Pull Shift built into the Treble pot lowers the frequency affected by the control and gives the amp a little extra mid-range boost in gain. The Bass Shift pull-out increases amplifier sensitivity in the lowest frequency range and the Middle serves to emphasize tonal body and warmth. All of the controls interact with one another to various degrees and thorough experimentation is the best way of discovering the wide range of musically useful sounds the D-180 can produce.

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