Specifications

INPUTS
Line:
The four line inputs (professional three-pin female
audio
connector+) are located on the rear panel and
designated "Line
1" through "Line 4." Inputs are
balanced (internal transformer,
mumetal shielded)
and connections are Pins 2 and 3 "hot," Pin
1
"ground."
Line 3 and Line 4 may be either 600 ohm line
termination or bridging, the choice being made by
the appropriate position of the "Bridge-Terminate"
switches above the Line 3 and Line 4 input connec-
tors. To obtain "Line" operation for the Line
1 and
Line
2 inputs, the corresponding "Line-Phono"
switch above the lnput 1 and lnput 2 controls on the
front panel must be in the "Line" position.
Impedances and operating signal levels are shown
in the "lnput Specifications" Section.
Phono:
The two phono inputs (RCA type phono jack) are
located on the rear panel and designated "Phono
1"
and "Phono 2." To obtain "Phono" operation for the
Phono 1 and Phono 2 inputs, the corresponding
"Line-Phono" switch above the lnput 1 and lnput 2
controls on the front panel, must be in the "Phono"
position.
The nominal "Phono" input impedance is 25 kilohms
resistive, 330
pF capacitive. In order to change the
resistive input to 47 kilohms, remove the 47-kilohm
resistors at "Phono" input terminals
(R226, R227).
When phono inputs are not being used, both "Line-
Phono" switches should be left in "Line" to con-
serve battery life.
CONTROLS
Individual lnput Gain Controls:
Front panel controls designated
"Input 1" through
"lnput
4" are the individual gain controls for corre-
spondingly numbered inputs. Note that the input
connectors are located on the rear panel directly
behind their corresponding control.
The lnput
1 and lnput 2 controls may be used to
control either "Line
1 - Phono 1" or "Line 2- Phono
2" inputs, respectively, depending upon the position
of the "Line-Phono" switch located immediately
above the lnput
1 and lnput 2 controls.
NOTE: The Line-Phono switches above Controls
1
and 2 are intended as SET-UP CONTROLS,
not operating controls. To conserve battery
life, these switches also control supply volt-
age to the phono preamplifiers. Hence, the
Line-Phono switches should not be thrown
while "on the air" unless the input controls
are both fully CCW
("0") to avoid introduc-
ing switching noise in the program material.
If phono inputs are not being used, both of
these switches should be switched to "Line"
to conserve battery life.
Monitor Gain Control:
This control is used to adjust the level of the front
panel monitor speaker, the front panel Headphone
jack, and the rear panel speaker jack. (See Cue
Operation below.)
tDesigned to mate with Cannon XL series, Switchcraft A3 (Q.G.)
series or equivalent connector.
OUTPUTS
Mix Bus:
The Mix Bus output is a shielded cable extending
from the rear of the M675 cabinet and terminated
with a phono plug. This cable should be connected
to the "Mix Bus" jack on the back of the M67 or
SE30 (use the "Aux Level Input" on the
M63). Once
this connection is made, the four M675 input signals
will be added and mixed with the M67, M63 or
SE30 input signals.
Front Panel Headphone Jack:
This jack provides both program and cue material to
600-ohm headphones. The "Monitor" control on the
front panel is used to adjust this headphone level.
The internal (or external) 8-ohm speaker is muted
when a plug is inserted into this jack.
Rear Panel
600 Ohm Headphone Jack:
This is a two-position jack for monitoring the output
of the M67, when the "Headphone" cable at rear of
M675 chassis is connected to the M67 "Headphone"
jack. The two-position phone jack is used to provide
a choice of level. Normally, a single circuit plug
should be used. If inserted only partially to the first
detent, the output level will be less than when
pushed fully in. If stereo phones are used, the
two-
position plug may be inserted fully and the output
will appear in both phones.
This jack is an extension of the two-level headphone
jack of the M67, and hence, it carries program
material only and its level is not controlled by the
monitor level control on the front panel.
While intended primarily for 600-ohm to
2-kilohm
headphones, this jack may be used with 8-ohm to
50-kilohm headphones, with resultant variation in
level. Crystal phones may also be used.
The "Tip" connections of the headphone plugs and
the two phono inputs are in phase with Pin 3 of all
input connectors on both the M675 and M67, and
with the tip of the Mix Bus connector.
Rear Panel 8-Ohm Output Speaker Jack:
This jack is for an 8-ohm high efficiency speaker or
for 8-ohm high quality headphones and provides
both program and cue material. The internal speaker
on the front panel is muted when the phone plug is
inserted into this jack. Use of the front panel
headphone jack, in turn, will
mute the internal (or
external) speaker. A mono (2 circuit) plug should
normally be used. If a stereo (3 circuit) plug is used,
external muting of the internal speaker is possible.
See schematic.
Monitor Speaker:
The internal speaker is activated unless either the
external
&ohm Output Jack or the front-panel 600-
ohm Headphone Jack is used. It monitors both
program and cue material.
OPERATION
Cue Operation:
The M675 "lnput" controls are in the Cue position
when rotated fully counter-clockwise and past the
detent.
With no M675 lnput Controls in the "Cue" position,
the monitor amplifier receives a program feed via
the connection to the M67 headphone output. The