Studio Technologies 220 2013 - Manual (Page 19)

Model 220 User Guide Issue 5, February 2013
Studio Technologies, Inc. Page 19
across the right side of their face, rather
than the more-typical left side. In this case
it’s important to select the left- and right-
channel headphone source assignment
accordingly. With the Model 220’s flexible
source selection there’s no reason why
users, such as on-air talent, shouldn’t have
their cue sources assigned correctly.
There may be cases where a monaural
“single-muff” headset or headphone will
be connected to the Model 220’s head-
phone output. In this case the desired
source(s) should be routed only to the left
channel. No sources should be assigned
to the right channel. This will eliminate the
short-circuit current that could occur when
a 2-conductor (monaural) plug is mated
with the Model 220’s 3-conductor (stereo)
headphone output jack.
Headphone Output Mode
Switch SW1-6 allows a monaural head-
phone output to be created. This is accom-
plished by summing (adding) the selected
left- and right-channel cue signals. The
combined signals are sent to both the left-
and right-channel headphone output driver
circuits. The outputs of these circuits con-
nect, by way of 100 ohm series protection
resistors, to the headphone output jack.
The headphone output monaural mode
feature was specifically included so that
a special “2-channel headphone mix”
mode can be created. By enabling the
mono mode, the two front-panel user level
controls (“pots”) can be used to create
the desired “mix” of signals being sent to
the headphone outputs. Many, many appli-
cations, especially in production settings,
can benefit from this capability. The desired
cue sources must be carefully assigned
to take advantage of the monaural mode.
The first cue source should be assigned,
using the DIP switches, to the left channel.
Its output level will be adjusted by the left
control. The second cue source should be
assigned to the right channel. Its output
level will be adjusted by the right control.
There is one limitation related to the head-
phone output mode. It’s the fact that the
output will be 2-channel monaural. What-
ever signal is present on the headphone
output’s left channel will also be present
on the right channel. (The exception is if
the right channel output is disabled using
the DIP switch setting.) A stereo head-
phone mix can’t be created. But in most
cases this limitation won’t overshadow the
benefit of being able to create the mix. For
signal-flow clarification please review the
block diagram located at the end of this
user guide.
Operating Modes
The sixteen switches associated with
switch assemblies SW3 and SW4 are
used to configure the Model 220’s operat-
ing modes. Technically, these switches
“talk” to the microcontroller integrated
circuit and associated software that give
the Model 220 its “smarts.” The software
has been carefully designed to provide
a number of different ways in which the
unit can function. It’s critical to carefully
review the available options and choose
the ones that best meet the needs of a
specific application. Note that switches
can be changed even while the Model 220
is powered up and operating. The unit’s
Figure 7. Headphone output mode settings