PROCEED AMP2, Инструкция

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17
Bridged Operation
Your Proceed amplifier has been designed to be extremely versatile. Should
your needs change or grow over time, you may wish to add additional power
by one of two means: Bridging, or Biamping. We will discuss bridged opera-
tion first.
Bridging Explained
Bridging refers to the act of reconfiguring the circuitry in both the left and
right channels of your amplifier to act as though it were a single, much larger
amplifier. (Of course, you will need a second bridged amplifier for stereo;
more for multichannel sound, as in home theater applications.)
Bridging is accomplished by sending a normal signal to one channel and an
inverted
signal to the other. In this configuration, one channel will always be
“pushing” when the other is “pulling.” By connecting the loudspeaker leads
across the left and right red output terminals, the amplifier can now deliver
twice the normal voltage to the loudspeaker. Working together this way, the
two amplifier channels can deliver almost
four times
the power to a speaker
that a single channel could deliver on its own.
Bridged operation is particularly beneficial with low sensitivity, high-imped-
ance loudspeakers (8
Ω
or higher) that have a greater need for voltage than for
current. It is not recommended for low-impedance loudspeakers, as the
speaker’s impedance is “split” by the two halves of the amplifier. Thus the
bridged amplifier “sees” a 2
Ω
load when connected to a 4
Ω
loudspeaker. De-
livery of high power into such a low impedance creates a great deal of heat
that needs to be dissipated. (Of course, your amplifier is protected against
overheating, but having an amplifier shut itself down even temporarily can put
a damper on the evening’s entertainment.)
Balanced Bridging
If your preamplifier has balanced outputs, you should use them. For this dis-
cussion, we will assume that you are using a Madrigal Balanced Bridging Kit
for each channel to be bridged. (Alternatively, you may have custom cables
built using your preferred wire and connectors, being careful to follow the
wiring diagram below.)
Balanced Bridging Kit
2 1
3
1 2
3
1 2
3
Female XLR Input
Pin 1: signal ground
Pin 2: (non-inverting)
Pin 3: signal – (inverting)
Male XLR Output (normal)
Pin 1: signal ground
Pin 2: (non-inverting)
Pin 3: signal – (inverting)
Male XLR Output (inverted)
Pin 1: not used (floated)
Pin 2: signal – (inverting)
Pin 3: (non-inverting)
Balanced Bridging
Input Adapter
(pin configuration)
Bridging Output Adapter
(not drawn to scale)
(shield not connected)