QSC Audio SPA-3 User Manual

SPA-3
Stereo
Precision
Attenuator

Owner’s

*TD-000100-00*

*TD-000100-00*

Manual

1

Rev. A

SPA-3 STEREO PRECISION ATTENUATOR

I. DESCRIPTION

The SPA-3 is a stereo preci­sion attenuator accessory
for use with DataPort­equipped 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 four­channel CX or DCA
amplifers) by using a
DataPort cable and a re­mote mounting rack. Ampli­fiers from the ISA series
cannot power the SPA-3, so
it requires a 15-volt exter­nal DC power supply when
used with one of them.

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Down

Shift

Up

Input
Stage

½

Micro-

controller

Signal
LED

Digital
Potentio­meter

8.8.

2-Digit
7-Segment
Display

To amplifier,
via DataPort

Output
Stage

Block diagram of one channel of the SPA-3

2