Input Socket; Hi/Lo Switch; Input Gain Rotary Control; Signal Level Leds - TRACE ELLIOT AH1000-12 Guide D'utilisation

(1) INPUT socket

This is to connect the 1/4" jack lead from your instrument. Alternatively, if any effect units are
being used before the amplifier then the output from the last unit is connected here. When the
INPUT is not in use the amplifier is automatically muted to prevent any unwanted noise.
Experience has shown us that not all 1/4" jack plugs are made equal, therefore, we recommend the
use of only high quality 1/4" jack leads for best sonic performance and reliable connection.
(2) HI / LO switch
This switch has two functions; to set the sensitivity and the impedance of the INPUT stage. In the
out position it is set HI for high sensitivity and high impedance (1MΩ). The in position is the LO
setting for lower sensitivity and lower impedance (100KΩ).
The difference in sensitivity is 10dB. Actual sensitivity is dependent on the setting of the INPUT
GAIN control.
Generally, this switch should be set to HI for passive instruments, which are usually high impedance
and have lower outputs, and LO for active instruments (those with batteries built in), which are low
impedance and often have higher outputs. However, either can be used as long as the INPUT
GAIN is set correctly.

(3) INPUT GAIN rotary control

This is to set the gain of the input stage of the amplifier. The setting of this control is the single
most important on the whole unit, hence why the control knob has a red cap.

(4) Signal level LEDs

The level indication LEDs are included to help the user set the INPUT GAIN control. The circuitry
monitors several strategic points throughout the preamp to determine if clipping (distortion) is
occurring.
The 7 Band units have 3 LEDs; green, yellow and red. Green will be lit for very low signal levels,
yellow will also come on when higher levels are present, and the red will be lit when the level is
clipping or close to clipping.
The 12 Band units have 5 LEDs. An extra green LED shows low to medium signal levels and the
additional red LED is a peak indicator that remains lit for a few seconds, even if the signal has
dropped in level. This is to show where clipping is occurring momentarily and might otherwise be
missed.
Ideally, the INPUT GAIN control should be set as high as possible with the red LED(s) only
lighting very occasionally when playing the instrument at its hardest.
The basic procedure is as follows:-
1) Set the INPUT GAIN and OUTPUT LEVEL to 0. Connect your instrument to the INPUT.
2) Set the HI / LO switch as appropriate for the particular bass being used.
3) Set the Volume control on the instrument to maximum.
4) Play the instrument as hard as it would be played during the performance.
5) While playing gradually turn up the INPUT GAIN.
6) The LEDs will begin to light up starting from the left.
7) Continue to turn up the INPUT GAIN until the (first) red LED is momentarily lit on the hardest
strokes, then back off slightly one or two clicks on the control.
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