ATC CA2 Operating Manual page 9

P r e a m p l i f i e r
2 . 1 D e s c r i p t i o n
The SCA2 is an extremely high resolution preamplifier designed to partner ATC
active, and, with an appropriate power amplifier, passive loudspeaker systems. It
incorporates eight line-level stereo inputs, two stereo signal outputs and two stereo
record outputs. Two of the line inputs are balanced format on XLR sockets while the
remaining inputs are unbalanced and on pairs of RCA phono sockets. The main
stereo output is balanced format on a pair of XLR sockets while the auxiliary stereo
output is unbalanced and on a pair of RCA phono sockets. The two record outputs
are unbalanced on pairs of RCA phono sockets.
The AUX 2 line-level input may be converted to function as a high-sensitivity phono
input through the addition of a factory fitted optional RIAA Phono Board. The RIAA
board carries an array of slide switches that enable optimal matching with phono
cartridges of various output voltages and loading requirements.
Selection of SCA2 inputs is achieved via a eight-position rotary control using gold
plated relays for silent switching. The SCA2 incorporates an independent record
output signal path so enabling simultaneous listening and recording of different source
signals. Selection of the record output signal is achieved via a second eight-position
rotary control using gold plated relays for silent switching.
Output volume adjustment is achieved through a precision motorised potentiometer.
Mute, gain and standby functions are also accessible from font panel push buttons.
Mains power is applied from a rear panel mounted switch.
All SCA2 functions are duplicated on the ATC SCA-Remote control handset.
SCA2
2 . 2 I n p u t s
The SCA2 can accept two balanced XLR inputs
and six unbalanced RCA phono style inputs (2 as
part of tape record/listen sets). The rear panel and
input sockets are illustrated in Diagram 1. The input
types and their identifying legends are illustrated in
following Table A.
The AUX 2 input sockets will function as a high-
sensitivity phono input if the optional SPH2 RIAA
Vinyl Board is installed. The RIAA circuitry can be
configured to accommodate a wide selection of
phono cartridge types by setting combinations of
board mounted links. Access to the board is gained
by removing the top panel of the preamplifier.
Diagram 2 illustrates the position of the links on
the board while Diagram 3 and Table B detail the
cartridge gain and input matching options
available.
Links are moved by pulling them gently away from
the board with a small pair of pliers and are
replaced in the appropriate positions as shown in
the diagrams. Unused links can be "parked" on the
board by setting them at right angles on unused
pins.
The SPH2 board is split into two identical channels.
For the sake of clarity on the diagrams, the settings
for only one channel are shown. Settings for one
channel should be duplicated on the other. The
cartridge gain and matching options should be used
as described below.
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