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NEUTRIK
INPUT
OUTPUT
GND
LIFT
LO-Z
OUTPUT
DIRECT BOX
CB-1
CB-1
StageMASTER™
CB-1
DIRECT BOX
FEATURES
• High Input Impedance Minimizes Loading for Maximum Sound
• Floating Transformer-Balanced XLR Output for Maximum Isolation
• GND/LIFT Switch Eliminates Hum and Buzz
• Handles Line-Level Inputs to +20 dBv at 20 Hz
• Rugged “Uni-box™” Construction for Super-Strength and Shielding
• Recessed Switches and Connectors Resist Damage
• Passive Design Requires No Batteries or Phantom Power
SERIES MODEL CB-1
FRONT OF UNITBACK OF UNIT
DESCRIPTION
The Pro Co Stagemaster CB-1 is a
simple passive direct box that offers
clean, reliable performance with nearly
any instrument or signal source,
including electric bass, acoustic guitar
pickups, keyboards, drum machines,
preamps and mixer outputs.
Using the CB-1 is a convenient,
low-cost alternative to mic’ing speakers.
It reduces distortion and coloration and
eliminates “bleed” and leakage from
other instruments. The signal delivered
to the P.A. or studio mixer is crisp, clean
and full - a vital element in retaining the
awesome bass and brilliant sound of
such current high-tech equipment as FM
synthesizers and digital-sampling drum
machines.
The CB-1 shares the heavy-duty
“Uni-box™” construction with Pro Co’s
premium Monoface DB-1 Direct Box.
The rugged 16-gauge steel and
aluminum box is finished in black with a
bold blue Lexan® overlay emblazoned
with high-visibility control and connector
identification graphics. The uniquely
slotted side channels allow for stacking
on top or strapping side-to-side of
virtually any number of Pro Co
Monoface devices using the Uni-box™
construction.
CONTROLS
INPUT:
1/4" (6.3mm) phone accept signals from
instrument or other source. Input
impedance-greater than 180 kohm.
Handles signals of up to +20 dBv at
20 Hz.
OUTPUT:
1/4" (6.3mm) phone jack provides
"loop-through" (parallel) connection from
input jack. Used when inserting CB-1
between instrument and amplifier.
LO-Z OUTPUT:
Male 3-pin XLR-type connector provides
balanced floating low-impedance output
(pin 2 hot). Connect to mixing board
microphone channel input.
Recommended load impedance: 1.0
kohm.
GND/LIFT:
GND position connects INPUT and LO-Z
OUTPUT grounds together. LIFT
position “floats” LO-Z OUTPUT. Used to
reduce hum and buzz by eliminating
ground loops and providing proper
grounding for various conditions.
NOT RECOMMENDED FOR
SPEAKER-LEVEL USE.
CB-1/041092
PRO CO SOUND, INC./135 E. KALAMAZOO AVE./KALAMAZOO, MI 49007 USA PRO CO
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StageMASTER
MODEL CB-1 DIRECT BOX
TYPICAL PERFORMANCE
All measurements made with 20 kohm source feeding INPUT
and 1.0 kohm load on LO-Z OUTPUT to simulate typical “real world”
instrument pick-up and mic preamp. 0 dBv ref. = .775 volt.
FREQUENCY RESPONSE:
20 Hz-20 kHz, +/- 1.0 dB @ -15 dBv output.
-3 dB @ approximately 57 kHz.
TOTAL HARMONIC DISTORTION:
Less than .1% 20 Hz-20 kHz @ -30 dBv output.
Less than .5% 30 Hz-20 kHz @ -15 dBv output.
Less than 1.0% 20 Hz-20 kHz @ -15 dBv output.
PHASE RESPONSE:
Less than -25 degrees @ 20 kHz (ref. 1.0 kHz).
RISE TIME:
Less than 6.0 microseconds (2.0 kHz square wave, 10%-90%).
INPUT IMPEDANCE:
Greater than 185 kohm @ 1.0 kHz.
Greater than 140 kohm @ 10 kHz.
Nominal source impedance is 20 kohm.
OUTPUT IMPEDANCE:
Less than 130 ohm @ 1.0 kHz.
Less than 155 ohm @ 10 kHz.
Nominal load impedance is 1.0 kohm.
ENGINEERING SPECIFICATIONS
The signal splitting/impedance matching unit unit shall be
suitable for interfacing one (1) unbalanced high- or low-impedance
source to one (1) balanced or floating low-impedance (1.0 kohm
nominal) microphone preamplifier input. There shall be two (2) 1/4"
2-conductor phone jacks wired in parallel to provide input and loopthrough output for the source. There shall be a transformer-isolated
low-impedance output from a 3-pin male XLR-type connector. The
transformer shall be a Pro Co CBT-1 Direct Box Transformer.
There shall be a ground-lift switch to allow the source ground and
pin 1 of the output XLR to be connected together or isolated as
required. The XLR output connector shall be wired with pin 2 “hot”
or “in-phase” with respect to the input, and pin 3 “cold” or “antiphase”.
The enclosure shall be constructed in the Pro Co “Uni-box™”
design with 16-gauge steel black zinc finish top and bottom plates,
16-gauge black texture powder coated steel end plates and black
anodized aluminum side channels. Control functions shall be
identified by a printed Lexan® top panel overlay. Switches shall be
of the miniature “rocker” type and shall be recessed. The enclosure shall be provided with two (2) miniature handles at each end
(front and back) and four (4) non-conductive feet. The dimensions
of the unit shall be 4.875" D x 4.375" W x 1.75" H (123.8mm D x
111.1mm W x 44.4mm H).
The signal splitting/impedance matching unit shall be a Pro Co
Stagemaster CB-1 Direct Box.
THE PRO CO CBT-1 TRANSFORMER
VOLTAGE STEPDOWN:
Less than 23 dB @ 1.0 kHz.
MAXIMUM INPUT LEVEL FOR 1% THD:
+20 dBv @ 20 Hz.
+26 dBv @ 30 Hz.
+32 dBv @ 50 Hz.
PRO CO MODEL CB-1
INPUT
RED
OUTPUT
BLU
BLU/WHTRED/WHT
CBT-1
TFMR
LO-Z
OUTPUT
The CBT-1 is a carefully designed, custom-built impedancematching transformer whose characteristics are optimized for use
with high-impedance sources such as electric bass guitars. It is
also very applicable to other unbalanced sources such as keyboard instruments.
Special winding techniques and a high-permeability (50%
nickel) core lamination preserve full frequency response while
minimizing signal losses and other "loading" effects. The source
impedance of the CBT-1 is very similar to that of a low-impedance
microphone to ensure proper matching to the input circuitry of the
mixer. The result is clean transient response (no overshoot or
ringing) and low distortion even at low frequencies and high input
levels.
DIMENSIONS
1
2
3
105.2mm
4.14"
4.375"
111.1mm
WEIGHT.......1.0 lb.
SHIPPING
WEIGHT.......2.0 lbs.
4.875"
123.8mm
0.45 kg.
0.91 kg.
1.75"
= CHASSIS
GND
LIFT
44.4mm
PRO CO SOUND, INC./135 E. KALAMAZOO AVE./KALAMAZOO, MI 49007 USA PRO CO
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