Crate Amplifiers SPA-1400 - Manual (Page 17)

1 7
SPA-1400/1400C
Rack Mount Power Amplifier
Speakon ® is a registered trademark of Neutrik USA
Installation and Operation:
Biamping: SPA-1400C – Multiple Amplifiers:
A single SPA-1400C can be used to power separate low and high frequency cabinets (shown below), and to connect addi-
tional biamped speakers, using multiple amplifiers. The MONO/STEREO SWITCHES (#16 & #17) must both be in the OUT posi-
tion. Here we show using channel 2 for the low frequencies and channel 1 for the highs – you may reverse the channels if
desired, as long as the
LOW/HI SEND SWITCH (#22) is set to “1/2” and the cabinets are reversed from what is shown below.
Since the SPA-1400C has a built in active electronic crossover, a separate external electric crossover is not needed – run the
output from the mixer directly into channel 1 of the amplifier. Use the
CROSSOVER FREQUENCY CONTROL (#24) to set the cut
off frequency for the low frequency cabinet. The LEVEL CONTROLS allow proper balancing of low and high frequency volume
levels.
Connect the additional amplifier/speaker combinations to the SPA-1400C’s BALANCED THRU/X-OVER jacks (#18). The
X-OVER OUT/THRU switches (#19) must each be pressed in.
Either the binding posts or the Speakon ® jacks may be used to connect the amplifier to the speakers. See the wiring dia-
gram below for the Speakon ® jacks.
You could also use the SPA-1400C for lows only, or even for full range, while still sending low and high crossover outputs
to the other amplifiers. Remember that the crossover is always active and crossover output is always available externally even
if the
X-OVER MODE switch (#23) is in the “off” position (not pressed in). (See page 6 for a review).
NOTE: Your speakers may benefit from a low frequency cut, since frequencies below a speaker’s low-end response limit can
cause distortion or even damage. For this reason you might consider using an appropriate Low Cut Frequency (see #20 & #21)
with your speakers (SPA-1400C only). (Even some subwoofers perform better with an appropriate low frequency cut.)