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I. DESCRIPTION
The SPA-3 is a stereo preci-
sion attenuator accessory
for use with DataPort-
equipped QSC amplifiers. It
mounts directly to the back
of two-channel CX, DCA, and
PL2 models, but it can be
used with the others
(PowerLight, ISA, and four-
channel CX or DCA
amplifers) by using a
DataPort cable and a re-
mote mounting rack. Ampli-
fiers from the ISA series
cannot power the SPA-3, so
it requires a 15-volt exter-
nal DC power supply when
used with one of them.
SPA-3 STEREO PRECISION ATTENUATOR
SNOITACIFICEPS3-APS
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k7.41,decnalab
ΩΩ
Ω
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decnalabnu
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ΩΩ
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SLORTNOC
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SRETEMARAPGNITAREPOELBAMMARGORP
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ssapyB lennahcrehtiE
Up
Down
Shift
½
Micro-
controller
8.8.
Digital
Potentio-
meter
2-Digit
7-Segment
Display
Input
Stage
Output
Stage
Signal
LED
To amplifier,
via DataPort
Block diagram of one channel of the SPA-3