Inovonics 235, Инструкция по эксплуатации и техническому обслуживанию

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This makes connection a bit easier and allows quick removal of the 235
from the rack should maintenance ever be required.
Balanced Input
A balanced program audio feed to the 235 Processor will use both the
+ and the – terminals, plus the associated G (ground). Since this is a
bridging (high impedance) input, it does not provide a ‘termination’ for
the console or other equipment which feeds the Processor. Should you
feel so compelled, you may connect a 600-ohm resistor across the +
and – input terminals, though the concept of 600-ohm “line matching”
dates from the age of transformer coupling and the mystique of
telephone lines with characteristic impedance.
Unbalanced
Input
In an isolated rare instance, the 235 might be fed from “semi-pro” gear
with an unbalanced output. In such an unlikely case, the single center
conductor of the shielded input lead should be connected to the +
terminal, and the shield to G . In addition, a jumper wire should be
installed between the – terminal and G .
Input Gain
Range
The Model 235 Processor can accommodate line-level program input
with a nominal “Zero-VU” value between –15dBu and +15dBu. This
30dB range is divided into two, more manageable 15dB ranges with an
internal jumper.
As shipped, the 235 is jumpered for professional level inputs between
0dBu and +15dBu. Most console and STL outputs fall into this range,
+4dBu, +6dBu and +8dBu being typical levels.
Lower levels, between –15dBu and 0dBu, may be encountered with
interfacing with “semi-pro” gear, or with feeds from leased telephone
circuits. The extra gain for the low level range is enabled by changing
a jumper beneath the top cover.
Gain Jumper
The input range jumper strip is located just behind the LINE INPUT
connector and identified as “JMP1” in the circuit board legend. The
jumper has an H and an L marking to indicate the proper jumper
placement for High level and for Low level inputs, respectively. Figure
5 illustrates these jumpering options.
LOW LEVEL INPUTS
(–15dBu to 0dBu)
HIGH LEVEL INPUTS
(0dBu to +15dBu)
Figure 5 - LINE INPUT Range Selection