Audio Developments AD149 - Manual (Page 54)

53
We have already stated our philosophy behind this module and the reason for the
omission of limited and limiting equalisation.
As with the mono line module, the stereo line module employs (two) double-balanced,
instrumentation-grade input amplifiers for optimum performance at line level. It is
important to notice that, unlike typical stereo modules, the two signal paths remain
separate from the input to the output of the module - thus enabling different
equalisation to be applied to each signal path.
For consistency, an L- or M-signal will be connected to input 1 and an R- or S-signal
will be connected to input 2. Should L & R or M & S be reversed on the tape, input
reverse - I P REV (2) - will correct the situation without having to replug.
It is ESSENTIAL the S-signal be on the right-hand path.
Following input reverse is a ganged, continuously-variable input-gain control (22). For
unity gain through the mixer, this potentiometer must be set at zero.
STEREO MODULE SIGNAL PATHS
FIG 10
Matrix 1 (1) and
matrix
2 (6)
enable the
creation of a
'Blumlein Loop'
within which all
Blumlein's
techniques
may
be applied.
Phase change (3)
on the right-hand
path
(S) will
reorientate the
L/R output from
the module when
the input is in the
M-S domain and
change the phase
of an R-signal
when the input is
in
the L-R
domain.
To follow are two
individually-
switched high-pass filters at 18dB per octave - one in each signal path. It is usual to