Studio Technologies Gen II - Manual (Page 5)

Generation II User Guide Issue 3, July 1991
Studio Technologies, Inc. Page 7
Signal Connections
All signal connections to and from the
Generation II are made via 3-pin XLR-type
connectors located on the back panel; one
female for line input, and two male for left
and right line output. For hum, noise, and
radio frequency pickup rejection, shielded
cable must be used. The shield should be
connected to pin 1 of the input and output
connectors. Pin 1 is electrically in common
with the Generation II’s power supply
ground, chassis ground, and power cord
ground leads. Following the European
convention, pin 2 is audio high and pin 3
is audio low. Maintaining consistent audio
input and output polarity is important for
correct performance. Failure to maintain
consistent left and right output polarity
will make the output audio not mono-
compatible.
The Generation II uses electronically bal-
anced input and output circuitry. Best per-
formance is achieved if the equipment
sending signal to and receiving signal from
the Generation II is operating in a balanced
mode. The input and output stages will
operate correctly in an unbalanced mode,
but selected performance characteristics
will be sacrificed. On the input side you will
lose the ability to reject common-mode
signals that balanced operation affords. On
the output side, you will lose 6dB maximum
output level. This is not a technical fault but
is inherent in electronically balanced output
stages. If unbalanced input operation is
required, strap the audio low to ground (pin
3 to pin 1). Connect input audio high to pin
2 and signal ground to the combined pins 1
and 3. If unbalanced output operation is
required, strap pin 3 to pin 1. Connect the
output audio high lead to pin 2 and signal
ground to the combined pins 1 and 3.
In broadcast settings, it is recommended
that the Generation II’s input and output
signals be connected via patch points.
Installation, testing, and servicing proce-
dures will be greatly improved if the unit can
be easily taken off line. Make sure that the
Generation II can be “patched around”
during testing and maintenance.
The Generation II’s line outputs are low
impedance, electronically balanced, line
level. They are capable of driving virtually
all line inputs (low or high impedance,
transformer or transformerless).
In most cases, transformer coupling be-
tween audio equipment is neither required,
nor desirable. If the equipment sending
signal to, or receiving signal from the
Generation II requires the isolation given
by a transformer, but does not contain
internal transformers, external transformers
can be added. Refer to the Technical Notes
section of this manual for recommended
transformers.
Connecting to Power
The Generation II may be operated from
either nominal 115Vac or 230Vac, 50/60Hz.
Units shipped to North America and Japan
are factory selected for 115V operation and
are supplied with a 0.50A 3AG fuse. Units
shipped outside North America or Japan are
selected for 230V operation and are sup-
plied with a 0.25A 5x20mm fuse. Before
connecting the unit to power, determine the
actual line voltage and check to see that the
voltage selector switch located on the back
panel is set to the appropriate voltage. If the
voltage selector switch is set for 230V, a
0.25A fuse is required; 115V requires
0.50A.