Pro Co MS83 Data Sheet

PRO CO MULTIFACE™ SERIES MODEL MS-83

MS-83

8-CHANNEL MICROPHONE
SPLITTER

FRONT OF UNIT

MICROPHONE INPUT

DIRECT OUTPUT

CHANNELS

1 4

BACK OF UNIT

GND/LIFT
1-2-3-4

GND/LIFT
1-2-3-4

ISOLATED OUTPUT 1

ISOLATED OUTPUT 2

MICROPHONE INPUT

DIRECT OUTPUT

CHANNELS

THRUTHRU

5 8

GND/LIFT
5-6-7-8

GND/LIFT
5-6-7-8

ISOLATED OUTPUT 1

ISOLATED OUTPUT 2

MS-83MS-83

V+

+48
IN

+48
OUT

FEATURES

• Provides 3-Way Split for Low-Z
Microphones

• 8 Splitter Channels in Single Rack Space

• Allows Assembly of Economical
Expandable Splitting System

• Great for Musicians’ Monitoring, Remote
Recording and Broadcast

• Connects with Phoenix COMBICON™
Plug-in Screw Connectors

• High-Quality Transformer-Isolated
Outputs

• Rugged "Uni–box™" Construction for
Super Strength and Shielding

DESCRIPTION

The Pro Co Multiface MS-83 Eight­Channel Mic Splitter splits the signals
from each of eight low-impedance
microphones (or similar sources) into
three outputs, enabling three microphone
preamplifiers to be fed from one source.
The primary application for the MS-83 is
in large sound reinforcement systems,
where the P.A. system microphones must
also be fed to a stage monitor system and
a broadcast or remote recording mixer.
In such complex systems grounding
problems can cause both unacceptable
noise levels and severe shock hazards.
Transformer isolation in such situations
minimizes interference from SCR lighting
dimmers, radio transmitters and 60 Hz
AC power wiring. The transformer­isolated feeds retain the advantage of
common-mode noise rejection inherent in
the use of balanced lines.

The MS-83 is fitted with Phoenix
COMBICON plug-in screw connectors
for MIC IN, DIRECT OUT, and ISO OUT
1 and 2, so hookup requires only bare
conductors and a screwdriver.

The use of the Pro Co MBT-2
transformer allows the MS-83 to provide
floating, low-impedance outputs with
wide, flat frequency response, ultra-low
distortion, and no ringing or overshoot to
degrade transient response.

The transformer’s triple electrostatic
shields and GND/LIFT switches provide
isolation and buzz-free operation in
virtually any environment.

The MS-83's rugged 16–gauge steel
and aluminum "Uni–box™" construction
enclosure is finished in a durable black
texture powder coat finish with black
anodized aluminum side channels. Easy–
to–read control graphics are incorporated
into the Lexan® front and back panel
overlays. Inside, the specially designed
transformers combine superb audio
quality with unsurpassed noise rejection.
The MS-83 can be mounted in any
standard 19" (482.6mm) rack. Top­quality connectors and switches provide
trouble-free service even in abusive
situations such as remote broadcast and
recording operations. The rack-mounting
design allows the user to assemble a
conveniently packaged expandable
splitting system that combines top­quality audio performance and isolation
with an economical price.

CONTROLS

MICROPHONE INPUT

Phoenix COMBICON plug-in screw
connector accepts signals from
low-impedance (150 ohm nominal)
microphones or similar sources. Input
impedance (with 1.0 kohm loads on
DIRECT and ISO OUTS) is
approximately 333 ohm.

DIRECT OUTPUT:

Phoenix COMBICON plug-in screw
connector wired in parallel with MIC IN
provides signal to feed mixer input.

ISOLATED OUTPUTS:

Phoenix COMBICON plug-in screw
connectors provide floating transformer­isolated low-impedance outputs to feed
mixer inputs. Recommended load
impedances: 1.0 kohm.

GND/LIFTS:

GND position connects pin 1 of MIC IN/
DIRECT OUT to pin 1 of ISO OUTS. LIFT
position “floats” ISO OUTS. Used to
reduce hum and buzz by eliminating
ground loops and providing proper
grounding for various conditions.

MS-83/042198

PRO CO SOUND, INC./135 E. KALAMAZOO AVE./KALAMAZOO, MI 49007 USA/www.procosound.com PRO CO

PRO CO MODEL MS-83 MICROPHONE SPLITTER

TYPICAL PERFORMANCE ENGINEERING SPECIFICATIONS

All measurements made with 150 ohm source feeding MIC IN and

1.0 kohm loads on ISO OUTS to simulate typical “real world” micro­phone and mic preamps. 0 dBv ref. = .775 volt.

FREQUENCY RESPONSE:

20 Hz-20 kHz, +/- .25 dB @ -15 dBv output.

-3 dB @ approximately 140 kHz.

TOTAL HARMONIC DISTORTION:

Less than .03% 20 Hz-20 kHz @ -30 dBv output.
Less than .1% 30 Hz-20 kHz @ -15 dBv output.
Less than .25% 20 Hz-20 kHz @ -15 dBv output.

PHASE RESPONSE:

Less than -13 degrees @ 20 kHz (ref. 1.0 kHz).

RISE TIME:

Less than 2.4 microseconds (2.0 kHz square wave, 10%-90%).

INPUT IMPEDANCE:

Greater than 570 ohm @ 1.0 kHz.
Greater than 570 ohm @ 10 kHz.

Nominal source impedance is 150 ohm.

OUTPUT IMPEDANCE:

Less than 255 ohm @ 1.0 kHz.
Less than 270 ohm @ 10 kHz.

Nominal load impedance is 1.0 kohm.

VOLTAGE LOSS:

Less than 2.5 dB @ 1.0 kHz.

MAXIMUM INPUT LEVEL FOR 1% THD:

0 dBv @ 20 Hz.
+4 dBv @ 30 Hz.
+8 dBv @ 50 Hz.

The microphone signal splitting unit shall be suitable for
interfacing each of eight (8) balanced or floating low-impedance
(150 ohm nominal) microphones or similar signal sources to
three (3) balanced or floating low-impedance (1.0 kohm nominal)
microphone preamplifier inputs. There shall be eight (8) channels
with features as follows:

There shall be a Phoenix COMBICON™ plug-in screw connec­tor for input from the source. There shall be a parallel or direct
output from a Phoenix COMBICON plug-in screw connector. There
shall be two (2) transformer-isolated low-impedance outputs
from Phoenix COMBICON plug-in screw connectors. The trans­former shall be a Pro Co MBT-2 Microphone Bridging Transformer.
The primary electrostatic shield
shall be connected to pin 'G' of the source input and direct
output COMBICON connectors. The secondary electrostatic
shields shall each be connected to pin 'G' of their respective
transformer-isolated COMBICON connector outputs. There shall
be a ground-lift switch for each isolated output to allow the
secondary shields to be connected to the primary shield or
isolated as required.

The enclosure shall be constructed in the Pro Co "Uni–box™"
design with 16–gauge steel black zinc finish top and bottom
plates, 1/8" black anodized aluminum front plates, back plates
and side channels. Control functions shall be identified by a
printed Lexan® front and back panel overlay. Switches shall be
of the miniature type and shall be recessed. The enclosure shall
be provided with 2 miniature handles mounted on the front
plate. The enclosure shall be suitable for standard 19" EIA rack
mounting. The dimensions of the unit shall be approximately 4­3/4" D by 19" W by 1-3/4" H. (120.7mm D by 482.6mm W by

44.5mm H).

The microphone signal splitting unit shall be a Pro Co
Multiface MS-83 Mic Splitter.

THE PRO CO MBT-2 TRANSFORMER

The MBT-2 is a carefully designed, custom-built 1:1:1 microphone
bridging transformer whose characteristics are optimized for use with
balanced low-impedance microphones or similar sources.

Special winding techniques and a high-permeability (80% nickel)
core lamination preserve full frequency response while minimizing
signal losses and other “loading” effects. Separate electrostatic shields
for primary (input) and each secondary (output) winding reduce
capacitive coupling of ground-borne electrical noise between main,
stage monitor and recording or broadcast feed mixers, eliminating
annoying 60-Hz hum and buzz. The source impedance of the MBT-2 is
very similar to that of a low-impedance microphone to ensure proper
matching to the input circuitry of the mixers. The result is clean
transient response (no overshoot or ringing) and low distortion even at
low frequencies and high input levels.

PRO CO MODEL MS-83

G

+

MIC IN

–

BLK/WHT

G

+

DIRECT

–

VIO/WHT

BRN

WHT

YEL

MBT-2
TFMR

ONE OF EIGHT CHANNELS

RED

BLK

GRN

BLU/WHT

PRO CO SOUND, INC./135 E. KALAMAZOO AVE./KALAMAZOO, MI 49007 USAwww.procosound.com PRO CO

GND
LIFT

GND
LIFT

G

ISOLATED

+

OUTPUT 1

–

G

ISOLATED

+

OUTPUT 2

–

DIMENSIONS

TOP VIEW

FRONT VIEW

SIDE VIEW

WEIGHT.......4.10 lbs.

1.86 kg.
SHIPPING

WEIGHT.......5.0 lbs.

2.25 kg.

19" / 482.6mm

4.75" / 120.7mm

1.75" / 44.5mm