T
he MB-100 is an electronics interface that powers
up to four Crown
®
mini-boundary™ MB-1, MB-2,
or MB-4/E microphones. This interface for four mics
reduces the size and cost of the microphone system and
reduces installation time.
The MB-100 provides programmable switching to turn
the mic on or off if desired (switches not provided). The
MB-200 interface also has remote switch sensing via an
optical coupler.
Two microphones can be wired to each pluggable terminal
block, which plugs into the MB-100 or MB-200 interface.
Pluggable terminal blocks are also provided for the bal-
anced outputs on the interface, and for remote switch
sensing.
The interface is powered by 18 to 48V phantom power
from a mixer or a phantom power supply.
Wiring Interface Mic Inputs
Before installing the mics, wire them to the included plug-
gable terminal blocks (PTBs) as described below:
1. For the MB-1 and MB-2 mics, solder the proper length
of cable to each mic jack as follows:
Sleeve (common ground) to cable shield
Tip (audio) to cable (+) lead
Ring (LED) to cable (–) lead
2. Wire the cables for two adjacent mics to the PTB as
shown in Fig. 2.
If you do NOT want the LEDs to light, disconnect the leads
from PTB terminals 2 and 5.
3. Similarly, wire MICS 3 and 4 (if used) to another
6-prong PTB.
Specifi cations
For microphone specs, see the individual data sheets for
the MB-1, MB-2 and MB-4/E.
Output impedance:
150 ohms, balanced (recommended
load impedance 1000 ohms or greater).
Polarity:
Positive (inward) pressure on diaphragm produc-
es positive voltage on output terminal 1 with respect to
terminal 3, and on terminal 4 with respect to terminal 6.
Operating voltage:
Phantom power, 18 to 48V DC on
output terminals 1 and 3 with respect to terminal 2, and
on terminals 4 and 6 with respect to terminal 5.
Operating temperature range:
–10° to +50° C, or +14°
to +122° F.
Current drain:
5 mA nominal per mic.
Cable connectors
(supplied with MB-100 or MB-200
interface):
• Pluggable terminal block (PTB) for connecting two micro-
phones to two mic inputs on the interface. Two of these
PTBs are supplied, for use with up to four mics.
• PTB for connecting two mic-level outputs to two mixer
mic inputs. Two of these PTBs are supplied, for use with
up to four mics.
• PTB for connecting two mic on/off switches (switches not
supplied). Two of these PTBs are supplied, for use with
up to four mics.
(MB-200 only)
PTB for external switch-closure sensing.
Each PTB connects to two external circuits (circuits not
supplied) that sense closure of the mic on/off switch.
Two of these PTBs are supplied, for use with up to four
mics .
Chassis connectors:
MIC1/MIC2 IN (connects to mics 1 and 2).
MIC3/MIC4 IN (connects to mics 3 and 4, if used).
MIC1/MIC2 OUT (connects to mixer mic inputs 1 and 2).
MIC3/MIC4 OUT (connects to mixer mic inputs 3 and 4,
if used).
MIC1/MIC2 SWITCH (connects to on/off switches for
mics 1 and 2).
MIC3/MIC4 SWITCH (connects to on/off switches for
mics 3 and 4).
MIC1/MIC2 external switch-closure sensing (MB-200
only).
MIC3/MIC4 external switch-closure sensing (MB-200
only).
Cable:
None supplied. For the MB-1 and MB-2, use two-
conductor shielded mic cable between phone jack and
pluggable terminal block. For the MB-4/E, the mic cable
is permanently attached to the microphone. Use two-
conductor shielded mic cable between interface output
and mixer input. Use twisted-pair cable between each
user switch and interface.
Materials:
Steel chassis.
Finish:
Satin black.
Net weight:
2 pounds, 5 ounces (1.048 kilograms).
Dimensions:
See Fig. 1.
9.31" (23.6 CM)
C-C
9.75" (24.8 CM)
8.89" (22.6 CM)
4.00" (10.2 CM)
C-C
.190" (0.5 CM)
DIA. HOLE
4 PLACES
1.06" (2.7 CM)
Fig. 1
MB-100 and MB-200 Dimensions
Wiring Interface Outputs
Please refer to Fig. 3. Repeat this wiring for another inter-
face output (if used).
Wiring Mic On/Off Switches
As supplied from the factory, the mics are always on. For
optional user control of each microphone, you can use
either a momentary or a push-on/push-off SPST switch
(not supplied). Proceed as described below:
1. Two switches connect to one pluggable terminal block
(PTB). Run a twisted pair from each switch to a 4-prong
PTB, and connect as described below (Fig. 4). Wire polarity
does not matter.
Fig. 4
Fig. 2
MB-100
MB-200
Fig. 3
2
6
5
3
1
PTB
4
TO INTERFACE “MIC 1 MIC 2 OUT”
TO MIXER
MIC 1 IN
TO MIXER
MIC 2 IN
4 AUDIO +
5 SHIELD
6 AUDIO –
1 AUDIO +
2 SHIELD
3 AUDIO –
Switch for mic 1 to PTB terminals 1 and 2
Switch for mic 2 to PTB terminals 3 and 4
2. Similarly, wire switches for mics 3 and 4 (if used) to
another PTB.
Wiring for External Switch-Closure Sensing (MB-200
only)
If external switch-closure sensing is desired, wire two
sensing circuits to one PTB as shown in Fig. 5. Repeat this
wiring for another pair of mics (if used).
Setting Internal Switch, Gating, and EQ Controls
Remove the MB-100 interface cover. Locate the four slide
switches, one for each mic (see Fig. 6). Set each switch to
one of these modes:
Push-on/push-off
Momentary on (press-to-talk)
Momentary off (mute or privacy button)
Set the low-cut and internal-gate defeat as desired for
each mic. Low-cut is –7 dB at 100 Hz.
2
6
5
4
3
1
PTB
TO MIC 2
TO MIC 1
TO INTERFACE “MIC 1 MIC 2 IN”
1 TIP (AUDIO)
2 RING (LED)
3 SLEEVE (GND)
4 TIP (AUDIO)
5 RING (LED)
6 SLEEVE (GND)
1 WHT
2 RED
3 SHIELD
4 WHT
5 RED
6 SHIELD
MB-4/E ONLY
1
2
3
4
PTB
1 SW1
2 SW1
3 SW2
4 SW2
TO INTERFACE
“EXTERNAL SWITCH”
TO SWITCH
FOR MIC 1
OR
AUTOMIXER
LOGIC OUT
TO SWITCH
FOR MIC 2
OR
AUTOMIXER
LOGIC OUT
Features
• Interfaces Crown MB-1, MB-2, or MB-4/E
microphones to a mixer with phantom power
• Interface powers up to four mics via phantom
power from mixer and provides four balanced
low-impedance outputs
• Pluggable terminal block (Phoenix type)
connectors
• MB-100 provides programmable mic switch-
ing
• MB-200 also has remote switch sensing via
optical coupler
MB SYSTEM
ELECTRONICS INTERFACE
