Focusrite ISA 428 Pre Pack, Руководство пользователя

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ENGLISH
3
Getting to know the ISA 428
Power
Applies power to the unit. Turn on the ISA 428 before
powering up devices to which the outputs are connected.
Instrument Inputs
Instrument sources may only be connected via the front
panel. Four unbalanced Instrument input connectors are
located to the far left of the front panel and are numbered
1-4, correlating to each of the four channels. These
connectors are used primarily for connecting low level
unbalanced signals such as those from passive guitars and
basses, or from active instruments such as keyboards and
electro-acoustic guitars.
Metering
Peak Meter and O/L LED
This moving coil meter has been designed to have a very
fast reaction time and a slow decay time, and so is perfect
for displaying and holding the peak level of the channel
signal during recording. The meter is fed with a signal taken
from the point in the channel path after the high pass filter
and before the insert send connector. The moving coil peak
meter reading therefore informs the user of the signal level
in the channel after gain has been applied by the pre-amp,
and also shows the level of the signal being sent to any
external equipment connected to the insert send output.
The meter is calibrated relative to the overload point of the
optional ADC card, (0dBfs on the meter refers to the
maximum level that can be converted by the ADC), and
relative to the analogue overload point, (where then 0dBfs
on the meter refers to an analogue level of +22dBu, 6dB
below the maximum analogue level available from the unit).
Within the meter is a hidden overload indicator marked
O/L that lights (red) when the signal in the channel exceeds
0dBfs (+22dBu), and acts as an additional safety feature for
monitoring peak signal levels.
Analogue/ADC dBfs Output meters
These vertical columns of LEDs indicate the peak signal
levels of channels 1-8 in one of two modes, the modes being
defined by the fitting of the optional ADC card as follows:-
Mode 1. Analogue only unit (no optional ADC card
fitted).
Meters 1 to 4 indicate the analogue level at the ISA 428
XLR output connectors for channels 1 to 4. 0dBfs (reached
when the red LED is lit) indicates that a signal level of
+22dbu is present at the output (–18dBfs) therefore