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
electronicequipmentisgroundedatonepointonly
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-
natemostproblemswithinterfering RFI (radio fre-
quency interference) and EMI (electromagnetic
interference). A properly conceived and imple-
mentedgroundingplan can save untold griefand
expense in trying to correct problems ‘after-the-
fact’.
InterInter
InterInter
Internal Equipment Rnal Equipment R
nal Equipment Rnal Equipment R
nal Equipment Racac
acac
ackk
kk
k
WW
WW
Wiringiring
iringiring
iring
Forbestperformanceandminimuminterference,
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.Varyingsignallevelsand/oracwiringshould
never be bundled or tie-wrapped in a common
riser.
ConnectionsConnections
ConnectionsConnections
Connections
Audio Input ConnectionsAudio Input Connections
Audio Input ConnectionsAudio 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
touseandconnectaccordingly. 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.Inthedual-channelmode,connectionsare
made to both channel 1 and channel 2. If the unit
istobeusedinbridgedmode,connectionismade
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:
AA
AA
Audio Output Connectionsudio Output Connections
udio Output Connectionsudio Output Connections
udio Output Connections
Alloutputconnectionsaremadeontherearpanel
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.
