EFFECTS LOOP JACKS — The serial “EFFECTS LOOP” jacks are
provided to allow access to the signal for the purpose of inserting signal
processing equipment such as compressors, chorus, delay & reverb
processors. Individual pre-EQ loops are provided for the TUBE channel
and the FET channel. An additional post EQ loop is provided for the
post-EQ summed (TUBE + FET) signal.
POWERFLEX SWITCH— This switch allows optimum matching of the
power supply to the speaker load. Similar in concept to output transformer matching in tube amplifiers, this feature allows the GBE-1200 to
drive 2 ohm loads at maximum efficiency compared to more traditional
designs. Driving 2 ohm speakers with the switch in the 4-8 ohm
position is not recommended as the amp’s monitoring circuitry
may reduce the output power to minimize stress on the amplifier. .
An amber “2 ohm” indicator LED is provided on the front panel to confirm that the 2 ohm POWERFLEX™ mode has been selected.
XLR DIRECT OUT — Studio Quality, fully active transformerless balanced DI. PRE/POST switch; GROUND switch; OUTPUT LEVEL Control adjustable between –50db and –10db. Fully protected from Phantom Power.
FOOTSWITCH INPUT — The GBE 1200 is fitted with a 6 pin DIN jacks
for the 5 button footswitch (included). In order for the footswitch to function correctly, the amplifier’s front panel switches for these functions
must be in the “out” position. This footswitch is unique to Genz Benz
due to the complex nature of it’s functions and must be factory supplied.
This operates the CHANNEL SELECT, MIX, LF EXTEND, MID SCOOP
and HF ATTACK functions. Th e front panel switches over-ride all
footswitch functions.
SPEAKER OUTPUTS — The GBE 1200 features 2 SPEAKON® NL4
connectors. Minimum total load impedance is 2 ohms. The SPEAKON
®
is wired using pins 1+ and 1-, pins 2+ and 2– are not connected.
REFER TO YOUR TECHNICAL MANUAL FOR
GENERAL SAFTEY INFORMATION
7811 E. Pierce St. Scottsdale, AZ 85257
Ph: 480-941-0705 Fax: 480-946-2412
www.genzbenz.com
Rev. 1
QUICK REFERENCE
MANUAL
IMPORTANT FEATURES:
• Blendable FET/12AX7 Tube Preamps— can be Switched or
Mixed
• Together via Footswitch (Footswitch included)
• 3 Circuit Shape Network (Footswitchable)
• LF Extend, Mid Scoop, HF Attack—All adjustable Min-Max.
• 5 Band Active EQ for each Channel
• High Powered Robust Output
• 550 Watts @ 8 ohms
• 1000 Watts @ 4 ohms
• 1200 Watts @ 2 ohms
• XLR Direct Out w/ Level Control, Pre/Post/Ground Lift Sw.
• High Velocity Heat Management w/ 2 Speed Fan
• Speakon® Speaker Outputs
• Unique “Soft Limit” Circuitry—Simulates Output Saturation for
warmer Limiting Action
OPERATION NOTES:
FRONT PANEL
INPUT — Selectable Active or Passive modes. Passive is a hi-gain
input and Active is –10db less. If your bass has a battery in it, choose
Active.
INPUT SIGNAL MUTE SWITCH — Mutes the signal from the amp and
also the D.I. The Tuner Out stays active. (Optional footswitch operates
the Mute function).
TUNER OUTPUT JACK — Plug your tuner in here. This output stays
active when the Mute switch is engaged.
CHANNEL AND MIX SWITCHES — The “TUBE/FET” switch provides
selection between the 2 preamp channels. The ”mix” switch in the channel section combines the two preamp channels together. These functions are footswitchable features. The front panel switches must be in
the out position in order for the footswitch to operate properly.
FET CHANNEL INPUT GAIN CONTROL & O/L LED — The “FET
GAIN” control, in conjunction with the red “O/L LED” (overload) , allow
you to adjust the FET preamp input gain sensitivity to the instrument
you are playing. Generally, you want to see only an occasional flash of
the red clip LED when you really hit the string hard, then adjust the “FET
VOLUME” control for playing volume. Distortion of the preamp gain
stage will occur when the red clip LED is illuminated, so plan accordingly.
TUBE CHANNEL INPUT GAIN CONTROL & O/L LED — The TUBE
channel operates the same as the FET channel, except that it is more
often desirable to operate the“TUBE GAIN” control higher, intentionally
overdriving the tube preamp for a more overdriven and distorted sound.
This action is indicated visually by the red “O/L LED” and generally requires a higher setting on the “TUBE GAIN” control and a lower setting
on the “TUBE volume” control. A blueLEDlights when the TUBE channel is active.
ACTIVE 5 BAND EQUALIZATION — The “active 5 band equalization”
used in the GBE 1200 amplifier is composed of 1 shelving low frequency control, 3 peaking midrange controls and 1 shelving high frequency control. The filters have a cut/boost range of +/- 12dB and a
smooth, musical sounding response. A separate 5 band equalizer is
provided for each the TUBE and the FET channels. This fully active EQ
has a wide range, so generally, a little EQ goes a long way.
GLOBAL SIGNAL SHAPING SWITCHES AND CONTROLS — Three
selectable voicing circuits that are Min.-Max. adjustable.
L.F. EXTEND — Lowers the low frequency roll-off to approx. 30 Hz,
producing a more pronounced low frequency rumble.
MID SCOOP —A wider bandwidth signal scoop centered at 800 Hz in
the mid response.
H.F. ATTACK —Increases 4K Hz freq. for more bite or string sound
when using a pick. All of these functions are footswitchable features.
All switches must be in the out position for the footswitch to operate
properly.
MASTER VOLUME —This adjusts the signal sent to the power amp.
Best results are achieved when operated between the 9 o’clock and 3
o’clock positions.
MASTER SECTION STATUS INDICATORS —
• The “power jewel light” indicates that the amplifier is on and the low
voltage power supplies are active.
• The red “PROTECT LED”indicates that the amplifier is in “protect”
mode and the output relay is de-energized. This LED will illuminate
for approximately 3 seconds during power switch-on and switch-off.
It will also illuminate during any internal fault condition. If this happens, turn the amp off and consult a repair technician.
• The red “THERMAL LED”indicates that the amplifier has over-
heated, engaged the protection circuit and shut down. This circuit is
self-resetting when the offending condition (blocked air vents, foreign
body stuck in fan, etc) is corrected.
• The amber “2 OHM” LED indicates that the power amplifier’s 2 ohm
POWERFLEX mode has been selected.
• The blue “SIGNAL LED” indicates that the power amplifier is receiv-
ing signal from the preamp.
• The red “CLIP-LIMIT LED”indicates that the power amplifier has
reached maximum power and/or the limiter threshold has been
crossed. Driving approximately 6dB beyond this point with the
“OUTPUT LIMITER” engaged, the amplifier will gradually begin to
clip.
OUTPUT LIMITER — Engages the internal “Soft Clip” Limiter. This limiting action is particularly musical sounding, even when driven hard.
A blue LED indicates that this feature is engaged.
REAR P A NEL FEATURES
TUNER OUTPUT JACK — A rear panel “TUNER OUTPUT” jack is also
provided. This output remains active when the “MUTE” switch is
pressed. The front panel jack is in parallel with the rear panel jack.
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