7
Operating Manual - Powerflex Multi-Channel Power Amplifier
7.
REAR PANEL FEATURES
7.1
Input Connectors
The Powerflex inputs use 1/4" tip-ring-sleeve (TRS) phone jacks, balanced XLR jacks, and balanced two piece
"Euroblock" style connectors. The three types of connectors are wired in parallel and may be used balanced or unbal-
anced. Use the euro-block connectors to daisy-chain multiple amps together . Input XLR jacks are pin 2 hot (+),
meaning that a positive voltage applied to pin 2 will result in a positive output voltage across the speaker terminals. Pin
2 of the XLR jack is equivalent to the tip of the 1/4" TRS jack.
Balanced Inputs
It is recommended that balanced input connections
be used whenever possible to take full advantage of the
amplifier's common mode rejection properties, and to reduce
ground-loop problems. The (+) signal is on pin 2 of the XLR,
and the tip of the phone jack. The (-) signal is on pin 3 of the
XLR, and the ring of the phone jack. If a hum problem per-
sists, try connecting a balanced signal to the Euroblock input
with the input cable's shield lifted at the amplifier end of the
cable (ie. no ground connection), but connected to ground at
the signal source. This eliminates potential ground currents
through the input cable yet preserves the benefits of shield-
ing.
Unbalanced Inputs
If an unbalanced XLR input connection is used, pin 3
should be connected to input ground (pin 1). If the 1/4" input
jack is used unbalanced, the use of a mono (tip-sleeve) plug
will automatically tie the (-) connection to input ground. Note:
Never float the (+) or (-) input connection when using an un-
balanced source. If connecting an unbalanced signal to the
Euroblock input, connect the signal to (+) and the cable shield
to both (-) and ground.
Mono Phone Plug
Unbalanced Connection
Tip (+)
Sleeve (Ground)
2=(+)
3=(gnd)
1=(gnd)
XLR Male
Unbalanced
Connection
Euroblock
Input Connector
- +
Ground
+ -
Signal (+)
(-) Input
Tied To
Ground
Unbalanced Audio Connections
Tip (+)
Ring (-)
Sleeve (Ground)
Stereo Phone Plug
Balanced Connection
XLR Male
Balanced
Connection
2=(+)
3=(-)
1=(gnd)
Euroblock
Input Connector
- +
Ground
+ -
Balanced Audio Connections
0
* Powerflex 6250 shown - Powerflex 4400
only has channels 1-4.
