3. Back-Panel
3.1. 12VDC Input
This is the power input for the Off-Ramp 4. The power from this input goes directly to
the voltage regulators, and any installed Superclocks or Ultraclocks, so the quality of this
power is critical. Upgrades here make an immediate difference in jitter. Average power
consumption is up to 500ma, depending on clock options, but much higher transient
currents are possible. The standard AC adapter included with the Off-Ramp 4 supplies
2.5 Amps @ 12VDC. The connector is center positive, 2.1mm and protected from
reverse voltage. To power-on the Off-Ramp 4, plug in the AC adapter and then connect
the DC power cable to the Off-Ramp 4. The included AC adapter is floating with respect
to the AC power ground, but grounded AC adapters can also be used.
3.2. USB Input
The USB input connects with a standard A-B USB cable to a computer or other
streaming USB audio source. The streaming rate limit is 24-bits, 192kHz. The USB
interface is asynchronous, so USB 2.0 compliant ports on the computer must be used.
The USB cable can be as long as 5 meters or 16 feet. To prevent application and
system crashes, it is best to close the music player application, such as iTunes or
Foobar
BEFORE
disconnecting the USB cable. Make sure that you load the USB driver
into the computer before connecting the USB cable for the first time.
It is recommended that you close your player application (such as Amarra, Pure Music,
Foobar etc.), before you unplug the USB cable from the Off-Ramp 4 or computer. Then
restart the application after the USB cable is reconnected.
