9
For best performance and to insure that the in-
stallation is free of ground loops that can create
obnoxious noise and hum problems, a technical
ground for the audio equipment should be
installed. In such a grounding system, the audio
electronic equipment is grounded at one point only
and with reference to the ac power connection to
the building (service entry). Depending upon the
size of the facility and the distance between the
equipment rack(s) and the service entry, a rela-
tively large ground conductor may be required to
establish a solid ground.
Do not rely on the building conduit/raceway
to provide a proper ground
Variance of ground potential between the
audio equipment and the service entry
should be <.25 Ohms.
Prior to commencing an installation, the design
of a well thought-out grounding plan can elimi-
nate most problems with interfering RFI (radio fre-
quency interference) and EMI (electromagnetic
interference). A properly conceived and imple-
mented grounding plan can save untold grief and
expense in trying to correct problems ‘after-the-
fact’.
Inter
Inter
Inter
Inter
Internal Equipment R
nal Equipment R
nal Equipment R
nal Equipment R
nal Equipment Rac
ac
ac
ac
ack
kk
kk
W
W
W
W
Wiring
iring
iring
iring
iring
For best performance and minimum interference,
internal rack wiring should be spaced with a
minimum of 4 inches (10 cm) between conduc-
tors having varying signal levels. That is, ac
wiring, input audio wiring, intermediate level
audio and output audio wiring should be
separated by a minimum of 4 inches from each
other. Varying signal levels and/or ac wiring should
never be bundled or tie-wrapped in a common
riser.
Connections
Connections
Connections
Connections
Connections
Audio Input Connections
Audio Input Connections
Audio Input Connections
Audio Input Connections
Audio Input Connections
All input connections are made on the rear panel
of the PA-4020B Power Amplifier. Each channel
is equipped with a 3-pin, screw-clamp, barrier-
strip type connector and a 3-pin, XLR-type con-
nector. Choose which type of connector you plan
to use and connect accordingly. Connections may
be made to either the terminal strip or to the XLR-
type connector; but not to both.
Both types of connectors have their respective
pins marked 1,2 and 3. Connections should be
made using the AES standard as follows:
Pin 1 – ground (shield)
Pin 2 – high (+) audio signal
Pin 3 – low (-) audio signal
Use two conductor, shielded cable for all audio
input lines.
Shields should be connected to ground at their
source end and not at the power amplifier.
Cable between the source and the power ampli-
fier should not exceed 18 inches (.5 meters).
Do not locate audio input cables closer than 4
inches (10 cm) from output, intermediate, or ac
wiring. See Grounding in the preceding Mounting
Section.
Determine whether the power amplifier will be
used in dual-channel mode or in the bridged
mode. In the dual-channel mode, connections are
made to both channel 1 and channel 2. If the unit
is to be used in bridged mode, connection is made
to channel 1 only. Make sure the bridge/stereo
selector switch is in the proper position for the
service intended.
See figure 2 for connection information:
A
A
A
A
Audio Output Connections
udio Output Connections
udio Output Connections
udio Output Connections
udio Output Connections
All output connections are made on the rear panel
of the PA-4020B Power Amplifier. Each channel
is equipped with a 2-conductor Neutrik
Speakon
connector and a pair of 4-way binding posts.
Choose which type of connector you plan to use
and connect accordingly. Connections should be
made to either the Neutrik connector or to the 4-
way binding posts; but not to both.
