User Manual

ABOUT THE 8PRE
10
■ Two 6-pin FireWire jacks
16 inputs and 12 outputs
When operating as a FireWire audio interface, all
8pre inputs and outputs can be used simulta-
neously, for a total of 16 inputs and 12 outputs:
All inputs and outputs are discrete. In other words,
using a mic input does not “steal” an input from the
ADAT optical I/O bank. The same is true for the
headphone outs and the main outs.
The two banks of ADAT optical ports provide eight
channels of input and output at 88.2 or 96 kHz. The
upper bank provides channels 1-4 and the lower
bank provides channels 5-8.
The headphone output can operate as an
independent output pair, or it can mirror any other
8pre output pair, such as the main outs.
Mic inputs with 48V phantom power
Eight rear-panel combo (XLR/TRS) jacks with
preamps, phantom power and 20 dB pad let you to
connect a microphone, guitar or any quarter-inch
input. The XLR jack serves as a low-impedance mic
input, and the TRS jack serves as a high-impedance
guitar/instrument input. Dedicated front-panel
trim knobs allow you to adjust each input indepen-
dently. Defeatable 48V phantom power and 20dB
pad are supplied by convenient front panel
switches.
Converters
All eight analog inputs are equipped with 24-bit
96kHz, 64x oversampling A/D converters. The
main outs have 24-bit 128x oversampling D/A
converters. All audio is carried to the computer in a
24-bit data stream.
Main Outs
The main outs are equipped with 24-bit 128x
oversampling D/A converters and serve as
independent outputs for the computer. The main
outputs are on balanced TRS +4dB quarter-inch
jacks. Both of these jacks can also accept
unbalanced plugs.
Optical
The 8pre provides two banks of optical “lightpipe”
jacks that support the ADAT optical digital I/O
format. At 44.1 or 48 kHz, the upper bank provides
eight channels of 24-bit digital audio, and the lower
bank simply mirrors all 8 channels of the upper
bank.
At 88.2 or 96 kHz, the upper bank handles
channels 1-4 and the lower bank handles channels
5-8 via the industry Standard S/MUX (“Type I”)
protocol for third-party product or MOTU’s own
“Type II” protocol for connecting the 8pre
optically to any MOTU audio interface. For details,
see “Setting the 2x optical mode” on page 29.
MIDI I/O
The 8pre’s standard MIDI IN and MIDI OUT jacks
supply 16 channels of MIDI I/O to and from the
computer via the 8pre’s FireWire connection.
Timing accuracy can be sample-accurate with host
software that supports it.
1394 FireWire
The two 1394 FireWire jacks accept a standard
IEEE 1394 FireWire cable to connect the 8pre to a
FireWire-equipped Macintosh or Windows
computer. The second jack can be used to daisy
chain multiple interfaces — up to four MOTU
Connection Input Output
Mic preamps 24-bit 96kHz on XLR/TRS combo 8 -
Main outputs 24-bit 96kHz on bal/unbal TRS - stereo
Headphone output - stereo
ADAT optical digital (from 44.1 up to 96 kHz) 8 8
Total 16 12
!8pre Manual/Mac Page 10 Tuesday, October 12, 2010 5:52 PM