Specifications

Model 9762 – Dual Combo Owners Manual
5. Signal Overload (OL) Indicator
This LED indicates signal overload/clipping conditions at the input gain block stages. In
normal use the LED should not light or flicker. Reduce the input GAIN switch to lower the
input gain and avoid clipping.
6. Output Level VU Meter
The five LED’s provide output VU Meter level indication sourced from the line output amplifier
at +6, +3, 0, -5 and –10 dB. The “0” LED indicates 0 dB output level referenced to +4 dBm.
7. +48V Phantom Power Enable
This switch enables +48V phantom microphone power on the rear microphone input
connector. The LED next to the switch lights when phantom power is active. The +48V switch
controls circuitry that ramps the 48V power up or down gradually to reduce unwanted bangs
or pops in the audio signal.
8. Microphone Low-Z Impedance Enable
This switch configures the input transformer for Low-Z impedance mode. The input
transformer and circuitry is optimized for 50-Ohm microphones or other devices having 50-
Ohm source impedance. In the non-depressed state the input transformer is configured for
200-Ohm source impedance. Note that the input signal level varies by approximately 6 dB
when the switch is operated. When changing impedances, adjust the gain switch to
compensate for the level change and to avoid masking the tonal differences between
impedance settings.
9. Polarity Invert Enable
This switch inverts the line output polarity (phase) in the depressed position. Note that this
switch operates a relay wired to the line output transformer and has no effect on the
unbalanced ¼ “ line output connector. Thus, the polarity of the unbalanced output is always
fixed in the non-inverted state. An alternative is to wire the balanced XLR output connector
for unbalanced operation as described in Section 4.3.
10. Gain Sensitivity Switch
The rotary gain switch has twelve positions that select the input sensitivity in 5 dB increments
from -20 dB to –75 dB for a maximum gain of 75 dB. The unit is set to maximum gain in the
fully CW position. Always start at the lowest gain setting and increase the gain to obtain the
desired output level.
11. Line Output Termination Enable
This switch enables the line output transformer termination resistor in the depressed state.
The transformer requires proper termination for optimal flat frequency response. This switch
is useful for bridging and balanced operating modes. In most cases the termination select
should be enabled for flattest response. Note that the response will exhibit a slight HF rise
around 20 kHz with no termination enabled. This technique may also be used to obtain
additional “air” in the signal path when desired. Experiment with the termination switch during
recording and note the effect on the audio signal while changing states.
12. Output Level Control
The output level control acts as a master fader to facilitate fine trimming of the output signal
level from –90 to 0 dB as required. In normal operation this control should be set to maximum
level (fully CW position) and then trimmed back as needed to obtain the desired output signal
level.
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