Studio Technologies 742A - Manual (Page 15)

Model 742A User Guide Issue 1, July 2012
Studio Technologies, Inc. Page 15
Audio Mixer
source for the tip lead (typically head-
phone left) is main output bus 1. The
audio source for the ring lead (typically
headphone right) is main output bus 2.
The levels of the two channels of the
headphone output are adjusted using
the dual-knob front-panel control.
Locating the headphone jack on the back
panel allows the installation of a remote
headphone jack at the exact desired loca-
tion. This eliminates having to plug head-
phones into the usual location on the front
panel of an audio mixer, which itself is typi-
cally mounted in a very crowded rack. The
problem of a draped headphone cord that
is easily snagged or tangled won’t occur.
As a suggestion, locating a headphone
jack on an I/O panel associated with a
PC-based editing location, voice-over
area, etc., can prove very useful.
There may be cases where the headphone
output may need to support a monaural
earpiece, such as at a talent voice-over
position. In this case, simply connect only
the tip and sleeve terminals for main out-
put bus 1 or the ring and sleeve terminals
for main output bus 2 on the 3-conductor
plug used to mate with the Model 742A’s
back-panel jack. Don’t use a 2-conductor
(mono) plug as the headphone output for
main output bus 2 will be shorted.
Connecting AC and/or DC
Power
The Model 742A requires a source of AC
mains or 10 to 18 volts DC for operation.
Either source can be connected with the
same result. Both can also be simultane-
ously connected if a redundant (backup)
power scheme is desired.
Connecting AC Mains Power
The Model 742A operates directly from
AC mains power of 100 to 240 volts, 50/60
hertz, 15 watts maximum. As a “universal
mains input” device, there are no switches
to set or jumpers to install. A 3-pin IEC
320 C14 inlet connector on the back panel
mates with a detached mains cord set.
(Refer to Figure 8 for a detailed view.)
Figure 8. Detail of back panel showing AC
mains power connector
All units are supplied with an AC mains
cord that has a North-American (NEMA
5-15L) standard plug on one end and an
IEC 320 C13 connector on the other end.
Units bound for other destinations require
that the appropriate cord set be obtained.
The wire colors in the mains cord should
conform to the internationally recognized
color code and be terminated accordingly:
Connection
Wire Color
Neutral (N) Light Blue
Line (L) Brown
Earth/Ground (E) Green/Yellow
Because the Model 742A does not contain
a power on/off switch it will begin opera-
tion as soon as AC mains power is con-
nected. To confirm that the Model 742A
is operating the LED indicator labeled
PWR/TONE will light. This LED is located