15
S T E R E O
Stereo Width
8
filter intervenes at low frequencies. If the M
ID
-H
I
T
UNE
filter is at 1 kHz, the
H
ARMONICS
filter affects higher frequencies. The characteristics of the two
filters therefore complement each other in an ideal fashion.
The I
N
switch switches the S
URROUND
P
ROCESSOR
on or off. The status-LED
indicates, that the S
URROUND
P
ROCESSOR
is activ. The I
N
switch works only
when the V
ITALIZER
A
CTIVE
switch is activated.
In case you want to monitor the S
URROUND
P
ROCESSOR
in isolation, switch
V
ITALIZER
A
CTIVE
on and set the P
ROCESS
and H
ARMONICS
control fully counter
clockwise.
The S
TEREO
W
IDTH
potentiometer controls the stereo image.
Working on estabilshed inter-channel phase principles, the S
TEREO
W
IDTH
control is be used to increase the subjective soundstage width of any stereo
source. The off-centre signals of the stereo source are detected and fed
back to the opposite channel phase inverted.
This effect can be applied to overall mixes as well as to single instru-
ments. Very interesting is the spreading of the stereo image of overhead
mics of drum-sets or choruses or horn sections.
Based around a toroidal transformer, the integral power supply is
designed to minimize induced hum and noise due to the non existence of
an air-gap.
On the XLR/jack-version (9320) the primary voltage may be selected
between 230V/50Hz and 115V/60Hz by means of a recessed slide switch
on the rear panel. The jack-version is set according to local requirements.
The XLR/jack-version (9320) features a rear-panel ground-lift switch
which may be used where ground loops are causing hum problems. When
the G
ND
L
IFT
switch is set to off, the circuit ground is no longer connected to
the chassis ground. The power cord connector is a 3-wire, U-ground, stan-
dard IEC mains connector for a detachable power cord (enclosed).
The unbalanced jack version (9319) has a two wire power cord obviating
the need of the ground lift switch.
Transformer, power cord and mains connector have VDE, UL and CSA
approvals. The fuse has a value of 200mA.
On the secondary side of the power supply, an RC combination is used to
filter out noise and hum voltages from the mains side. Both half-waves are
smoothed with 2200
µ
F capacitors in the positive and negative voltage
path. Both pathes are calibrated separately via trimmers, as deviations of
only a few millivolts can result in audible changes such as a diffuse sound
pattern. After the calibration stage, the current is again smoothed.
Power supply
Surround
Processor
In
7
