8
– CXA120
CXA120 –
9
XLR Balanced Wiring
Pin 1 = Shield
Pin 2 = Hot (+)
Pin 3 = Cold (–)
1/4" TRS Phone Plugs and Jacks
“TRS” stands for Tip-Ring-Sleeve, the three connections
available on a stereo 1/4" or balanced phone jack or plug.
TRS jacks and plugs are used for balanced signals and
stereo headphones.
1/4" TRS Balanced wiring
Sleeve = Shield
Tip = Hot (+)
Ring = Cold (–)
1/4" TS Phone Plugs and Jacks
“TS” stands for Tip-Sleeve (famous Olympic hurdler), the
two connections available on a mono 1/4" phone jack or
plug. They are used for unbalanced signals.
1/4" TS Unbalanced Wiring
Sleeve = Shield
Tip = Hot (+)
RCA Plugs and Jacks
RCA-type plugs (also known as phono plugs) and jacks
are often used in home stereo and video equipment and
in many other applications. They are unbalanced and
electrically equivalent to a 1/4" TS phone plug.
RCA Unbalanced Wiring
Sleeve = Shield
Tip = Hot
5. THERMAL CONSIDERATIONS
The power amplifier within the unit is convection cooled
rather than fan cooled. Heat is drawn away from the
amplifier by the heatsink and radiated through the cooling
vents in the top cover.
When installing, be sure to allow sufficient air space
around the top and rear of the amplifier to allow
adequate cooling for the heatsink. Leave at least one rack
space above and below, and at least 6 inches behind the
chassis to allow proper ventilation.
If the amplifier should overheat, a thermal switch turns
off the power amplifier, allowing the heatsinks to cool
down. Once the amplifier has cooled to a safe operating
temperature, the thermal switch resets and reactivates
the amplifier. If this should occur, identify the cause of the
problem and take corrective action. For example:
• Provide better ventilation
• Install a fan in the rack to move more air
• Make sure the amplifier is not overloaded with too
low of a load impedance or by a short circuit on the
speaker line
RACK MOUNTING
Two rack ears are provided to allow the unit to be fitted
within a standard 19" rack.
Remove two front screws from each side, and securely fit
each rack ear in place. The unit still needs to be supported
underneath, due to the weight of the power and output
transformers.
6. CONNECTIONS
Here are some common audio connectors and their internal
wiring. This may help you wire up to the screw terminal inputs
of your unit. You can see which pins of the connectors are
usually hot, cold, or ground.
On your unit:
BAL1 = Hot (+)
COM = Shield
BAL2 = Cold (–)
XLR Connectors
XLR connectors are commonly wired as follows (according
to standards specified by the Audio Engineering Society):
2
2
3
1
1
SHIELD
COLD
HOT
SHIELD
COLD
HOT
3
SHIELD
COLD
HOT
3
2
1
SLEEVE
TIP
TIP
SLEEVE
TIP
SLEEVE
TIP
SLEEVE
TIP
SLEEVE
SLEEVE
TIP
SLEEVE
TIP
RING
RING
TIP
SLEEVE
RING
BALANCED INPUT
BAL1 COM BAL2
TEL PAGING
T
R
G
COM
