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P A C I F I C
M I C R O S O N I C S
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Model Two HDCD
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User’s Manual
Rev. C - January 2002
Setting Analog Input Attenuation
Analog input attenuation is set in 1 dB steps allowing a peak input signal level over the
range of +24 dBu to +12 dBu to produce full scale digital record level. The Model Two is set
at the factory to +18 dBu, which is a typical peak signal level (With an operating level of
+4 dBu, and headroom of 14 dB, the peak level will be +18 dBu.). Analog input level
attenuation is set by placing jumpers on pins located behind a cover panel on the Processor’s
rear panel, directly above the XLR analog input connectors. To access the jumpers, remove
the two thumb screws holding the panel in place. The pins and jumpers are located as
follows:
The twelve pairs of pins on the left set Channel 1 and the twelve pairs of pins on the right
set Channel 2. Placing the jumpers on the outermost pair of pins on each side provides
maximum input sensitivity; a +12 dBu input signal will generate full scale record level.
Each position inward of the jumpers produces 1 dB of attenuation. Placing the jumpers on
the innermost pair of pins on each side produces 11 dB of attenuation, which will then
require a +23 dBu input signal for full scale record level.
If no jumpers are installed, 12 dB of attenuation is produced, requiring a +24 dBu input for
full scale record level. The unused jumpers should be stored horizontally across two pins,
as shown below, to keep them secure.
Jumpers set for +12 dB
+12
+12
+18
+18
+23 +23
Jumpers set for +23 dB
+12
+12
+18
+18
+23 +23
No Jumpers set for +24 dB
+12
+12
+18
+18
+23 +23