Genz-Benz 904 ユーザーガイド
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FRONT PANEL CONTROLS
(Left to Right)
BOOST SWITCH — Increases the amount of gain to the tube by 10dB. The switch is overridden when a
footswitch line is connected to the “Boost” jack on the rear panel. Very useful when you want to empha-
size a lead or add rare crunch and drive for a short period.
BYPASS SWTTCH — Switches the unit in and out of the effects chain. The Red LED is lit when the unit
is active in the chain. This switch is also overridden when a footswitch is connected to the "Bypass" jack
on the rear panel.
is active in the chain. This switch is also overridden when a footswitch is connected to the "Bypass" jack
on the rear panel.
DRIVE CONTROL — Also can be thought of as a "Volume" control. This control sets the pre-amp gain
of the tube pre-amp section. When the cleanest sound is preferred (little distortion) set this control in the
low range (usually "6" or less) and set the "Master" control on "10". As the "Master" setting is reduced,
and the "Drive" setting is increased, more tube distortion will result.
of the tube pre-amp section. When the cleanest sound is preferred (little distortion) set this control in the
low range (usually "6" or less) and set the "Master" control on "10". As the "Master" setting is reduced,
and the "Drive" setting is increased, more tube distortion will result.
CONTOUR CONTROL — Adjusts the amount of low frequencies or bottom end driven into the tube.
Some players prefer a fatter texture to their sound, while others prefer a more articulated, less "muddy"
contour. Moving this control toward "10" gives a fatter sound. Moving this control toward "0" will roll off
the extreme bottom end. Overdrive use: It is usually advisable to use less bass with chords, while single
string or note leads may sound better with more bottom end.
Some players prefer a fatter texture to their sound, while others prefer a more articulated, less "muddy"
contour. Moving this control toward "10" gives a fatter sound. Moving this control toward "0" will roll off
the extreme bottom end. Overdrive use: It is usually advisable to use less bass with chords, while single
string or note leads may sound better with more bottom end.
BIAS CONTROL — Actually adjusts the amount of cathode bias voltage of the tube stages, thereby
regulating the amount of plate current. Non-technically speaking, this control has the effect of adjusting
the overdrive characteristics from "hard" or "metallic" to "soft" or "compressed." A "10" setting gives the
hardest, most direct sound. "8" actually gives the most sensitivity and warmth, but with some softening
starting in. "0" may become too "mushy," but let your ears tell you what’s best for your application. Note:
Some DC noise is normal in this control when rotated.
regulating the amount of plate current. Non-technically speaking, this control has the effect of adjusting
the overdrive characteristics from "hard" or "metallic" to "soft" or "compressed." A "10" setting gives the
hardest, most direct sound. "8" actually gives the most sensitivity and warmth, but with some softening
starting in. "0" may become too "mushy," but let your ears tell you what’s best for your application. Note:
Some DC noise is normal in this control when rotated.
MASTER CONTROL — Sets the overall output level of the rack.
HI CONTROL — Adjusts high end. Set at 1500 Hz and higher.
MID CONTROL — Adjusts mid-range frequencies. Center is 500-800 Hz.
LOW CONTROL — Shelves off lower frequencies from 100 Hz down.
POWER SWITCH — Supplies main AC power to the unit. The Green LED is lit when the power is on.
REAR PANEL LAYOUT
(Left to Right)
LINE CORD — Be sure to connect the unit to the proper voltage source. The current draw is negligible.
A maximum of only 6 watts is consumed, but the unit can be damaged be proper voltage ratings are not
adhered to.
LINE OUT JACK — Line level out jack. This level will drive basic power amps, and operate at normal
line levels (0 dBV).
line levels (0 dBV).
INST. OUT JACK. — Instrument level output jack. This output should be used to conned the unit to the
input of a regular "combo" or stage amplifier "instrument" input. Instrument levels are generally used in
amplifier effects loops.
input of a regular "combo" or stage amplifier "instrument" input. Instrument levels are generally used in
amplifier effects loops.
LINE IN JACK — Line level input jack. This can be particularly useful in the studio and with line-level
equipment (0 dBV nominal levels). NOT A REGULAR GUITAR INPUT!
equipment (0 dBV nominal levels). NOT A REGULAR GUITAR INPUT!
INST. IN JACK — Normal instrument input. This input would also be used for low level (normal) effects
loops on most amplifiers. NOTE: The use of this input and the "Line Out" jack enables the rack to act as
an instrument pre-amp for basic power amps. The "Inst. Out" jack should be used for normal effects loop
operation.
loops on most amplifiers. NOTE: The use of this input and the "Line Out" jack enables the rack to act as
an instrument pre-amp for basic power amps. The "Inst. Out" jack should be used for normal effects loop
operation.
FT. SW. BOOST & BYPASS JACKS — Permits the use of standard "on-off" footswitches to remotely
switch the "Boost" and "Bypass" functions. Front panel "Boost" and "Bypass" switches are automatically
overridden with footswitch use.
switch the "Boost" and "Bypass" functions. Front panel "Boost" and "Bypass" switches are automatically
overridden with footswitch use.