MOTU Audio Express User Manual page 21

direct connection to the power supply harness
inside your computer. This is the same power
supply harness to which you connect internal hard
drives, CD/DVD drives, etc.
PCMCIA or ExpressCard slot adapters — If you
■
plan to connect the Audio Express to a PC card
FireWire adapter (inserted in the PC card slot in
your laptop), it must provide a 6-pin connection
and it must also have its own power supply. Most
commonly, these types of products have a DC
power adapter. As you can see, however, this
situation does not allow for remote battery
operation, as the PC card adapter requires AC.
Examples of bus- powered operation
Here are a few typical examples of bus-powered
Audio Express operation:
Bus power from a desktop computer
Your desktop computer is running off of its usual
AC power connection, and the Audio Express
draws power from the FireWire cable connected to
the computer. There are no limits to running time.
Bus power from an AC-powered laptop
This scenario is identical to the desktop situation
described above: the laptop is powered by AC, the
Audio Express is powered via the FireWire bus and
there are no limits to running time.
Bus power from a battery-powered laptop
The laptop is being powered by its own battery, and
the Audio Express is being powered by its FireWire
connection to the computer. So the laptop battery
is supplying power to both the laptop and the
I N S T A L L I N G T H E A U D I O E X P R E S S H A R D W A R E
Audio Express. This is the most compact and
portable operating scenario. Running time is
determined by the capacity of the laptop battery.
For extended recording sessions, bring extra, fully
charged laptop batteries.
DC power supply
If you do not want the Audio Express to draw
power from the computer, and AC power is
available, you can power the Audio Express from
any standard 9-18 volt, 5 watt DC power supply
with any polarity (tip positive or negative), and
amperage as shown below.
Voltage
9 volts
12 volts
18 volts
Turning off the Audio Express
To turn on the Audio Express, push the PHONES
volume knob. To turn it off, push and hold the
PHONES volume knob. When the Audio Express is
turned off, it is really in a sort of "sleep" mode,
where it still draws just enough power to detect the
power switch (a digital encoder) when the Audio
Express is turned back on. But the amount of
power that the Audio Express draws when it is
turned off is so small that it has very little practical
impact. If you are running a laptop under battery
power, and you are in a situation where you are not
using the Audio Express and you need every last bit
of laptop battery power, unplug the Audio Express
entirely from the computer.
Amperage
1.33 amps
1 amp
0.66 amps
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