User Manual

HD I/O Guide8
Analog Input
The HD I/O Analog In card contains connectors
for analog audio input with 24-bit, 192 kHz A/D
converters. Input is provided through two dis-
crete DB–25 connectors (one for +4 dBu sources,
and the other for –10 dBV sources). You can
connect sources at both operating levels and
choose between them from within Pro Tools.
+4 dBu Balanced Provides eight balanced input
channels at +4 dBu nominal operating levels.
–10 dBV Balanced Provides eight balanced input
channels at –10 dBV nominal operating levels.
For wiring information, see Appendix B, “Pin-
out Diagrams for the DB-25 Connectors.”
For each channel, you can select input level
from within the Hardware Setup dialog (see
“Hardware Setup” on page 17).
Input Trims
The Input Trims below the DB–25 connectors
are used to individually calibrate each channel’s
input level. See “Input Trims” on page 26.
Additionally, the Limiter function helps avoid
digital clipping (see“Limiter” on page 22).
Analog Output
The HD I/O Analog Out card contains a single
DB–25 connector and Output Trims for eight
channels of analog audio output. These bal-
anced outputs operate at +4 dBu levels. See
Appendix B, “Pinout Diagrams for the DB-25
Connectors.”
Output Trims
The Output Trims below the DB–25 connector
are used to individually calibrate each channel’s
output level. For more information, see
Appendix C, “HD I/O Calibration Mode Instruc-
tions.”
Most consumer electronics operate at –10 dBV
levels, and may not feature balanced inputs
and outputs. You can connect –10 dBV
signals to the –10 dBV inputs, but you will
need to make sure that the negative terminals
are not connected.
For –10 dBV gear, you can switch a jumper
on Analog Output cards (on a channel-by-
channel basis) from the default Hi position
to Lo for a –6 dB pad. You can then adjust
the Trim pot for the corresponding output
channels by an additional –4 dB to accom-
modate –10 dBV gear. For more information,
see Appendix C, “HD I/O Calibration Mode
Instructions.”