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.
Low Frequency - 80 Hz and below
Low-Mid Frequency - 200 Hz
Mid Frequency – 500 Hz
High-Mid Frequency – 1250 Hz
High Frequency - 4000 Hz and above
Global Signal Shaping Switches and Controls
— There are 3 separate shaping fi lters on the GBE 750. The “L.F.
EXTEND” (low frequency extend) lowers the low frequency roll-off response of the preamp (between 30 and 45 Hz)
to allow the full effect of 5+ string and extended scale instruments. The amount of extension is adjustable depending
on the setting of the corresponding control. Use this function with care due to the power of this amplifi er. The “MID
SCOOP” function introduces a midrange scoop at approximately 800 Hz, with a lower “Q” than typical equalization
provides. The amount of scoop is adjustable with the corresponding control. The “H.F. ATTACK” (high frequency
attack) function increases brightness and sparkle (approximately 4KHz) of the signal, allowing exaggeration of
percussive effects and string sound. The amount of attack is adjustable with the corresponding control. All 3 fi lters are
footswitchable with the 5 button footswitch. A bright blue LED located above each switch indicates when the fi lter has
been selected. All switches must be in the out position in order for the 5 button footswitch to work properly.
Master Volume
— The “master volume” adjusts the signal level sent to the power amplifi er. Best results are usually
obtained when this control is set between the 9 o’clock and 3 o’clock position.
Output Limiter
— The “output limit ” switch engages or bypasses the internal power amplifi er’s soft clip limiter. This
limiter allows simulation of output stage saturation as the amplifi er nears its maximum power. The limiting action is
particularly musical sounding, even when driven hard. A bright blue LED located above the switch indicates when this
feature has been selected.
Master Section Status Indicators
—
• The “POWER LED” indicates that the amplifi er is on and the low voltage power supplies are active.
• The red “PROTECT LED” indicates that the amplifi er 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 is normal for this LED to glow
while continuing to monitor the internal conditions for a few seconds after the protection relay has closed. 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 amplifi er has overheated, 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 amplifi er’s 2 ohm POWERFLEX mode has been selected. This
LED monitors the operation of the high voltage power supplies.
• The blue “SIGNAL LED” indicates that the power amplifi er is receiving signal (over several watts output) and all is
well!
• The red “CLIP-LIMIT LED” indicates that the power amplifi er has reached maximum power and/or the limiter
threshold has been crossed. Driving approximately 6dB beyond this point with the “OUTPUT LIMITER” engaged, the
amplifi er will gradually begin to clip.
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