Rane MA 6 1988 version - Manual (Page 5)

INSTALLATION
Diagram 1 shows three basic wiring configurations for the MA 6:
1. Direct operation.
2. Biamp operation.
3. Bridged operation.
NOTE — AUTOMATIC INPUT COUPLING
The MA 6 uses switching input jacks to automatically make internal connections between
each pair of channels:
1 & 2, 3 & 4, and 5 & 6. Whenever a signal is plugged into an odd-
numbered channel (channel 1, forexample), the next even-numbered channel is automatical-
ly driven INVERTED (out of phase, so to speak) as long as no input is plugged into its own jack
(in this case channel 2). As soon as a signal is plugged directly into the even-numbered
channel, the internal connection is defeated and both channels operate independently.
You can use this feature a couple of ways:
1. AUTOMATIC BRIDGING Plug into any odd-numbered channel, but DO NOT
plug an input into the next even-numbered channel. Then connect a single 8 ohm or greater
speaker cabinet between the two HOT terminals of the above two channels of the MA 6—you
are now running bridged power (300 watts into 8 ohms) into the speaker cabinet.
2. RUN TWO CHANNELS MONO FROM A SINGLE INPUT: You can run any pair of
channels with a single input, thereby driving two speaker cabinets with the same signal. Run
the input into the odd-numbered channel ONLY-do not plug anything into the next even-
numbered channel. Then connect one speaker normally to the odd-numbered output
terminals, but connect the second speaker IN REVERSE: speaker positive to MA 6 ground
(–), amplifier positive to speaker ground. This way both speakers will be in phase and you will
have saved yourself a cable and two connectors.
FAN INFORMATION
The cooling fan in the MA 6 requires a bit of special attention during installation. There should
be adequate room between the fan filter and whatever may be located behind the amplifier
for sufficient cooling air to enter the unit. This is normally quite easy to accomplish in most rack
installations.
This fan is of the two speed variety, which means that under most operations the fan will run at
a very low speed, switching to high gear only during extended high power demands. The
amplifier will deliver a full 100 watts into six discrete eight or four ohm loads for several
minutes before switching to high speed. Once the high power demand has been reduced or
removed the fan will return to low speed in a matter of a minute or two.