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..-------CAU
TION------.
INPUT MATR IX SWITCHES
Do not actuate
any
switches on the
crossover
driver
module
while pri-
mary
ac power is tu rned on
.
Failure to
observe this precau
t
ion will introduce
a large transient
w
hich may cause
damage to loudsp eakers connected
to
the
system
.
OUTPUT MATRIX
SWITCHES
I
S201
I I
S101
I
I
S401
I I
S301
I
ATTENUATION
SWITCHES
I
SS03
I
I
S502
I
I
S501
I
I
ssoo
I
BRIDGING
SWITCH
S402
Matrix switches
S101, S201,
and S301 con-
nect the
high-freque ncy
,
mid-frequency
,
and low-frequency driv er amplifier circuits
to
the inputs
of
the
power amplifier mod-
ules
.
For example,
to
route
high
frequency
signals to power ampli
fi
er module
#1,
close
the
#1
output matrix switch of
S301.
To
route low frequency si gnals to power amp-
lifier
modules
#4
and
#5,
close output
matrix switches #4 and
#5
of S101.
Figure 15. Typical SA Type Driver
Module
(Model
2252
SA Shown)
A study of
the
Modular Block Diagram will
indicate a variety of co
nf
igurations to dis-
tribute signals
for
bia mplification
and tri
-
amplification
.
Note tha
t t
he biamplification
mode
of
operation
enables
the
mid-
frequency driver amplifi er circuit to be used
as a
full
range driver amplifier, with level
control
,
by connecting
th
is signal source at
special input/output
ja
ck
J214; see appli
-
cations example given in Figure 20 for an
illustration of this case
.
possible
misrouting
of
driver
output
signals
.
Bridging
Switches
Bridging switches
are provided
on
the
Models 2250 and 2252 Driver
Modules to
bridge outputs of
two
(or two equ ivalent
sets)
of power amplifier modules
for a
bal-
anced 70-volt (or 49-volt
in
modified version)
output. Refer to Figure 12 and
appropriate
paragraphs under OUTPUT CONNECTIONS.
The
bridging
switch for
the Model 2250
Driver
Module
is designated S202; see Fig-
ure
14.
Bridging switches
for the
Model
2252 Driver
Module
are designated
S202
and
S402. Always leave
the
bridging sw
it
ches
OFF (open) unless the application specifi-
cally requires
closure for a bridged
con-
figuration.
Bridged switching is identical for
SA
type
modules
.
Attenuation Controls
An attenuation control is provided for
each
driver amplifier circuit of the drive
r
module
.
Attenuation
is
continuously
adjustable
from Oto - 60 dB for Models 2250,
2251
and
2252.
See Figure 14. Step attenuato
rs
are
provided
for the
SA type modules,
adj
ust-
32d
B
SWITCH
16dB
SWITCH
8d
B
SWI
TCH
4dB
SWITCH
2dB
SWITCH
1 dB
SWITCH
CLOSE
SWI
TCHE
S
BY
DEPRESSING ROCKER
TO
LEFT
(ADD
ATT ENUATION)
OPEN SWITCHES BY
DEPRESSING
ROCKER
TO RIGHT
(REMOVE
ATTENU
AT ION)
Figure
16.
Attenuation
Switch ing
of
SA
Type Driver
Modules
able
in
increments
of 1 dB from 0 to
-
63
dB
.
See
Figure
15. A
study of
the
modular
block
diagram
illustrates that
the
attenu-
ati
on
controls
are
especially
useful to es-
tablish several signal
levels from a single
source
signal.
Attenuation Switching of
SA Type Driver
Modules
SA type
driver
modules
are equipped with
step att
enuators
.
Six attenuation switches
for
each
driver
amplifier
circuit provide
1,
2,
4,
8,
16
and 32
dB attenuation.
By closing
the switches
in
various
combination, any
atte nuation may
be
obtained in
1
dB steps
,
to
a
maximum
of
63
dB.
See Figure
16.
For
example, closing
switches 1,
2,
and 5
pro-
vide
an attenuation
of 19 dB.
Electronic
Crossover
Switching
The op
tion of elect
ronic crossover is pro-
vided on
the
Model 2251 Crossover Driver
Module;
see Figure
17.
Two-way
or
l
hree-
way crossover operation
may be selected
with Bl/TRI
switc
h
S3.
Crossover frequen-
cies
may
be select
ed with switches S1 and
S2.
Swi
tches S1
and S2 each have four posi-
tions
to select cro
ssover
frequencies
as
indicated
in
Figure 17.
TRI
t-
B1/TRI
SWITCH
S3
Bl
HF DRIVER OUTPUT
MATRIX SWITCH
S301
LF
DRIVER
OUTPUT
MATRIX SWITCH S101
Filter output lines 10, 11 and 12 respectively
feed
the low
,
mid
,
and high frequencies to
the input of a Model 2250 or 2252 Driver
Module,
and
to
the special
input/output
jacks J213,
J214,
J215,
and
J216.
Thus the
low, mid, and high frequ
ency
outputs of the
crossover driver modul
e
are accessible to
feed another Increment al Power System, a
Model
9440 Power Amplifier,
or other
device.
Rated load impedance
of
low, mid, or high
frequency direct
filter
out
puts of the cross-
over driver is 3000 ohms
mi
nimum.
MODULE EXTENDER
CARDS
Module
extender cards permit any of the
system
modules
to
remain
operational
·
when physically
remov ed from the main
frame
.
This facilitates fi
nal
adjustments of
the
input and driver mod
ules,
and simplifies
troubleshooting
.
Use th
e
Model 2299 Ex-
tender Card with any
input
module or driver
module; use
the three
adjustment nuts
to
MID- HIGH
FREQ UENCY
SWITCH S2
N
N
N
N
::c:
::c:
::c: ::c:
0000
0001/)
ooo.--
00
1/)
q- (')
ATTENUATION
CONTROLS
LOW
-M
ID
FREQ UENCY
SWIT
CH
S1
NNNN
::c: ::c: ::c: ::c:
0001/)
0Ll)ON
CON COCO
,- ,-
Figure 17.
Electronic
Crossover Switching
for Model
2251
Driver
Module
10
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