Sound Performance Lab EQ MAGIX - Manual (Page 12)

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Input
Mic / Line
Line -30 B
The I NPUT stage of the EQ MAGIX is based on the SSM 2017 semicon-
ductor. The strengths of this particular component are its extremely low noise
and distortion characteristics. Unlike discretely designed circuits, the SSM
2017 has 64 transistor functions (discretely up to 24), thus achieving a
common mode rejection of over 90 dB (measured at I NSERT S END ).
Preamplification of the input signal is determined by the M IC /L INE
control. The control range of the preamplification values ranges from +7dB
to +65 dB. The maximum amplification value specified is a minimum
value. The preamplifier stage provides up to +75 dB. This value can be
lower, depending on the tolerance of the potentiometer, but it never falls
below a value of +65 dB.
When setting the M IC /L INE value, take note of the transducer type
(condensor or dynamic microphone) and the free-field transmission factor
of the microphone type. The sound pressure level of the sound source to be
recorded, the distance to the microphone and the room acoustics are other
factors which also have to be taken into account when setting the M IC /L INE
potentiometer. The free-field transmission factor of a dynamic microphone
is around 2mV/Pa, that of a condensor microphone can be up to
20mV/Pa, which equals an increase in the output level of 20 dB.
The EQ MAGIX can also be used as a gain-on amplifier for Line signals.
The input sensitivity of the preamplifier stage is reduced by 30 dB by pres-
sing the L INE -30 dB switch. The corrected preamplification value on the
M IC /L INE control can be ascertained by subtracting 30 dB from the value set
on the potentiometer.
Alternatively, line signals can also be looped in via I NSERT R ETURN .
However, in this case, it is not possible to match the level, (see I NSERT - page
14).
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Control
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