Aphex Project Channel - Manual (Page 4)

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2.6 POWER SUPPLY
Soft-start, overload foldback limiting, and across-the-
line voltage spike protection is incorporated to protect
the power supply from damage that might be caused
by component failure or power line disturbances. If
the internal fuse blows out, a catastrophic failure has
occurred and simply replacing the fuse will not fix the
problem. Due to the extensive protective measures
used, it is highly unlikely a catastrophic power supply
failure will ever occur. However, if it does, you should
contact the factory or a competent service technician
to affect repairs. There are no user serviceable parts inside.
2.7 AC LINE CONNECTION
The Project Channel is internally powered from a standard
IEC power receptacle on the rear panel. Be sure you use a
power cord that is approved for use in your jurisdiction.
The Project Channel’s internal power supply is designed
to operate from all nominal power sources from 100 to
240 volts a.c. at 50/60Hz without requiring the user to
change any settings.
2.1 INSTALLATION
The Project Channel occupies a single rack space
(45mm or 1-3/4 inches) of a standard EIA equipment
rack.
When rack mounting, use appropriate cushioned rack
screws. Try not to position the Project Channel directly
above devices that generate excessive heat such as
power amplifiers.
2.2 REAR PANEL VIEW
2.3 S/PDIF DIGITAL OUTPUT
The processed signal is converted to digital in both chan-
nels at equal level as a mono signal. Simply select S/PDIF
(L) or (R) as the input in your DAW. The S/PDIF output
uses a 75 Ohm coaxial (RCA) connector.
2.4 OUTPUT CONNECTORS
There are two output connectors located on the rear
panel: one 1/4” TRS phone type and one XLR-3M type.
They can be used at the same time to feed separate equip-
ment.
The output level at the XLR is +4dBu impedance balanced,
while the TRS balanced/unbalanced jack is switchable
between -10dBV (consumer level) and +4dBU (profes-
sional level).
If you intend to make an unbalanced output from the
XLR jack, simply take “hot” from pin 2 and use pin 1 for
ground. Leave pin 3 unconnected or grounded. Never
ground pin 2.
2.5 MIC INPUT CONNECTION
The microphone input uses the standard XLR-3F type.
Use only properly wired balanced mic cables.
3.1 USING THE MICROPHONE INPUT
The Project Channel is perfect for all types of micro-
phones. Dynamic, condenser, ribbon, etc. We encour-
age you to try every mic you own with the Project
Channel.
If the clip LED is flashing RED, then the input signal
is too hot. Turn the input gain knob down until the
light no longer flashes red. If the input gain knob is all
the way down and the clip light still flashes, engage the
-20dB pad.
3.2 USING THE INSTRUMENT INPUT
The Project Channel can also be used as a high quality
direct box. When an instrument cable is plugged in to
the Instrument input on the front panel, the rear panel
XLR input is bypassed. This allows the user to keep
a microphone connected to the rear panel and simply
insert an instrument cable in to the front panel instru-
ment input when D.I. functions are required. You will
be able to achieve proper input levels no matter what
kind of pickups are used. Single coil passive pickups
will work just as well as active humbuckers. Be aware
the single coil pickups can receive hum from electrical
fields in the air. Hum from single coil pickups can be
reduced or eliminated by repositioning the guitar. Buzz
can not be canceled, it can only be dealt with by con-
ductive shielding installed in the wiring cavities of gui-
tars and must be grounded.
3.3 USING PHANTOM POWER
Active microphones that take power through the stan-
dard mic cable fall into a class called “phantom pow-
ered” mics. The power is called “phantom” because it
rides the mic cable invisibly, without interfering with
the audio signal carried on the same wires.
The industry standard phantom power source is posi-
tive 48 volts d.c. (+/- 10%) supplied to pins 2 and 3
through precision low noise 6.81KΩ resistors.
Plugging and Unplugging a microphone when phan-
tom power is on can sometimes damage a mic because
of power inrush. Switch off the phantom power first
and wait for the mic to go silent before unplugging.
3.4 USING THE POLARITY SWITCH
Phase reversing can be helpful when using multiple
microphones on the same source. For example, using
two microphones on a guitar speaker cabinet. You
may get a “nasal” or hollow effect when both mics are
on. Changing the polarity of one mic will often clear
up the problem. It is always worth the time to experi-
ment with mic polarity.
3.5 USING THE PAD
The -20dB pad is an attenuator that drops the level
coming in to the input. Its purpose is to give you a way
of preventing overload of the preamp when incoming
signals become excessive.
In the Project Channel, we provided a pad of -20dB.
That means when the pad is on, the net gain of the
preamp is 20dB lower. There are times that the input
may be overloaded even with the GAIN control set all
the way down. For example, a bass player with active
pickups and an aggressive playing style might peak the
instrument input. Or a microphone on a kick drum or
snare drum could do it. Engage the pad and 26dB of
headroom will be provided allowing you to better con-
trol the input signal.
3.6 USING LOW CUT
In the real world, mics pick up all sorts of unwanted
low frequencies such as handling noise, wind rumble,
etc. We designed into the Project Channel a very effec-
tive way of cutting out these low frequencies. Switching
on the LOW CUT FILTER rolls off all frequencies below
70Hz at 12dB per octave.
3.7 USING THE COMPRESSOR
2.0 INSTALLATION & INTERFACING 3.0 USING THE PROJECT CHANNEL
CAUTION: Some ribbon mics will be damaged by
phantom power. Please consult your ribbon mic’s
manual before connecting it to the Project Channel.
CAUTION: Shut off the phantom power before plug-
ging or unplugging microphones, waiting at least 10
seconds for the voltage to fall. This also protects sensi-
tive microphones against power inrush.