Toa MX-401 Instruction Manual

POWERED MIXER
Operating Instruction Manual
Model MX-401
Toa Electric Co., Ltd.
KOBE, APAN

General Description
Features
Front Panel [Names of components & their usage]
Rear Panel [Names of components & their usage]
Connection Examples
Input Connections
Bloc and Level Diagrams
Specifications
Characteristics Diagrams
Appearance
2
2
3
4
5
6
7
8
9
9
1. XLR Type Audio Connector
The connectors are wired as follows.
The pin 1 is ground (shield), the pin 2 cold (low, minus), the pin 3 hot (high, plus).
2. Description of components and functions on the MX-401.
Various descriptions are applied, depending on each manufacturer. In our
Operating and Instruction Manual explanation of components and functions is
made according to our usage for them.
Contents
recautions

The TOA MX-401 is a very compact, four channel self-powered mixer. It was
designed to deliver maximum features and performance in a cost-effective portable
PA pac age.
The MX-401 features four input channels, one program output, and one Foldbac
output. The internal amplifier is rated at 100 watts into an 8 ohm load, and 150 watts
into 4 ohms.
Each input channel has an electronically balanced XLR connector, and a high-
impedance unbalanced 1/4" phone jac . In addition, each channel features two-band
EQ, a pre-EQ Foldbac send, and post-EQ reverb send.
The master control section features a patchable 5-band graphic equalizer, a quality 3-
spring reverb, a full patch bay with 1/4" phone auxiliary and RCA tape inputs, and
master volume controls for Program, Foldbac , and Reverb return to both. The power
amp protection circuitry and autocomp compressor, both with LED's, are also located
in this section.
1. Four input channels
2. 100 watts into 8 ohms, 150 watts into 4 ohms
3. Patchable 5-band graphic EQ
4. Auto Comp compression unit w/LED
5. Built-in spring reverb
6. Power amp protection circuitry w/LED
7. Full patch bay
8. Aux input w/level control, RCA jac s and parallel phone 1/4" jac s.
9. Reverb level to PGM and FB
10. Independent Foldbac mix.
Each Channel
1. Input level control
2. Two band EQ
3. Pre-EQ Foldbac send
5. Low-Z electronically balanced XLR input
6. Hi-Z unbalanced 1/4" input
— 2 —
General Description
Features

High Equalizer Control
(HIGH)
The high EQ control alters the
high frequency response of the
input channel, providing ±13dB
at 10 Hz, and ±15dB at 20 Hz of
continuously variable active
shelving equalization. The "0"
detented position provides flat
audio response.
Low Equalizer Control
(LOW)
The low EQ control provides
±13dB at 100Hz and ±15dB at
50Hz of continuously variable
active shelving equalization.
The "0" detented position pro-
vides flat audio response.
Reverb to Foldback
Control (REV TO FB)
This control adjusts the amount
of reverb signal that is returned
to the foldbac buss and thus the
level of reverb contained in the
on-stage monitor mix.
Reverb/Control
(REV)
This control determines the
level of signal assigned to the re-
verb mixing buss. Rotating the
control cloc wise increases the
amount of reverb in that channel.
Foldback Control (FB)
The Foldbac control deter-
mines the level of signal assign-
ed to the foldbac mixing buss,
thus setting the level of that
channel in the on-stage monitor
mix.
Graphic Equalizer
(EQUALIZATION)
The graphic equalizer is 5 inde-
pendent active bands (filters),
providing 12dB of boost or cut at
each center frequency. The "0"
detented position provides flat
audio response.
Foldback Master Control (FB)
The FB master control adjusts
the overall combined signal level
of the four independent channel
foldbac sends, and thus the
level of the entire on-stage moni-
tor mix.
Aux Level Control (AUX)
This control sets the overall level
of the Aux input signal.
ower Amp Compression
Indicator
(COM )
The Comp LED lights when the
internal compressor is activated.
The compressor is provided to
protect spea er systems by com-
pressing the input signal level of
the power amplifier when clip-
ping occurs in the output stage.
Frequent flashing of the LED is
not reason for alarm. However, a
constant or steady light indicates
that the MX-401 is being over-
driven and that the internal
power amplifier is possibly
"under powered" for that applica-
tion. The output level of the MX-
401 should be decreased until the
LED only flashes intermittently.
ower Indicator LED
( OWER)
The indicator LED lights when
th e power s witch is "on".
Input Level Control
(LEVEL)
The level control provides con-
tinuously variable adjustment
of the channel output to the
program mixing buss, thus
determining the level of that
channel in the main sound
system mix. Since the reverb
signal is "post" this control, an
increase in the level of the
channel's output will also result
in a corresponding increase in
the reverb effect of that channel.
The nominal level of the input
level control is at the "10" posi-
tion.
High Impedance Connectors
(HIGH Z)
These connectors are unbal-
anced, standard 1/4" phone jac s
with an input impedance of 27
ohms, and an input level of
—35dB. When a plug is inserted
into the high -Z input, the cor-
responding XLR connector is
automatically switched out of the
input circuitry.
Low Impedance Connectors
(LOW Z)
The XLR connectors are low im-
pedance, electronically balanced
inputs with an input impedance
of 1 ohms.
Reverb to rogram Control
(REV TO GM)
This control adjusts the amount
of reverb signal that is returned
to the program buss and thus the
level of reverb contained in the
main sound system.
rogram Master Control
( GM)
The PGM control adjusts the
overall combined signal level of
the four independent channel
level controls, and thus the level
of the main sound system.
Aux Input Jacks
(AUX IN)
The phone jac and RCA pin
jac s are wired in parallel, with
an input level of —20dB. When a
plug is inserted into the phone
jac , the RCA pin jac s are
automatically switched out of
the AUX circuitry.
Foldback Output Jack
(FB OUT)
This jac is for connection to
external power amplifiers and/
or equalizers for the on-stage
monitoring system. Nominal
output level is +4dB with an
impedance of 600 ohms. If the
internal power amp and equal-
izer are to be used for the on-
stage monitor system, the FB
output should be connected to
the GEQ input jac .
rogram Output Jack
( GM OUT)
The PGM Out jac is provided
for connection to external equal-
izers and/or power amps, deriv-
ing its signal prior to the internal
GEQ and power amp. Nominal
output level is +4dB wit h an
impedance of 600 ohms.
Graphic Equalizer Input Jack
(GEQ IN)
The GEQ input jac allows the
graphic equalizer to be used in-
dependently of the MX-401 with
other external equipment, or the
internal power amplifier and the
graphic equalizer with external
equipment. When a plug is
inserted, the main mix from
the program buss is disconnected
from the graphic equalizer and
the power amplifier. The nomi-
nal input level is +4dB with an
input impedance of 50 ohms.
Graphic Equalizer Output Jack
(GEQ OUT)
This jac allows the MX-401
and the internal graphic equal-
izer to be used with an external
power amplifier, or in conjunc-
tion with the GEQ in jac , to be
used independently of all other
MX-401 circuitry. Nominal
output level is +4dB with an
impedance of 600 ohms.
ower Amp rotection
Indicator ( ROTECT)
The indicator LED lights if the
power amplifier output is short-
ed, if the temperature of the unit
rises above acceptable levels, or
if DC is drifted to the spea er
outputs. If the LED should light,
spea er wiring and ambient
temperature of the MX-401
should be chec ed. If the LED
remains lighted, the unit should
be referred to qualified service
personnel for repair.
Note:
The MX-401 protection circuitry
will (1) detect 'faulty conditions'
within the power amplifier, (2)
give a visual indication, and (3)
automatically shut down until
the fault condition is alleviated.
This special circuitry ensures
maximum reliability and vir-
tually eliminates equipment
damage due to unsafe or fault
conditions. Please refer to fault
protection table on page 4 for
full explanation of this im-
portant feature.
ower Amplifier Input Jack
( WR IN)
The PWR Amp input jac allows
the internal power amplifier to
be used with external equip-
ment. When a plug is inserted,
the power amp is automatically
disconnected from the MX-401
mixer section. The nominal in-
put level is +4dB with an input
impedance of 10 ohms.
— 3 —
Front anel

ower Switch ( OWER)
The power switch is a three-
position type with the middle
position being the "off position.
The MX-401 should be operated
in the switch position which
produces the lowest amount of
system hum.
Speaker Jacks (S EAKERS)
The spea er outputs are stand-
ard 1/4" phone jac s wired in
parallel. Spea er cables (recom-
mend at least #18 gauge wire)
should be connected between
the MX-401 and the spea er
systems prior to applying power
to the unit.
Caution - The MX-401 should
never be operated into less than
a 4 ohm spea er load.
Earth Terminal (GND)
AC ower Cord
The power cord is the three-wire
type with proper grounding faci-
lities.
Caution - The ground pin should
not be removed under any cir-
cumstances. If the MX-401 must
be used without proper ground-
ing facilities, a suitable ground-
ing adapter should be utilized.
Operation of the MX-401 with
proper grounding techniques
will result in less system noise
and greatly reduced shoc
hazard.
Cord Wrap
The cord wrap is provided for
convenient storage of the power
cord w h en t h e MX-401 is no t in
use.
Caution - The power cord should
always be completely removed
from the cord wrap prior to
operation of the unit. This will
insure maximum cooling of the
MX-401 For the same reason,
adequate clearance should be
maintained between the rear
panel and any other surface (4-6
inches should do). The vents on
the bottom and top of the MX-
401 are also provided for convec-
tion cooling. These ve nts should
be ept clear and open. Failure to
do so may cause thermal shut-
down of the unit.
AC Fuse
Warning - To avoid possible
equipment damage and/or per-
sonnel injury, the fuse should
always be replaced with same
type and rating. Using improper
fuses will also void the warran-
ty. The MX-401 should always
be disconnected from AC outlet
prior to changing fuses. If fuse
repeatedly fails, the unit should
be referred to qualified service
personnel for repair.
Fault rotection Table
Fault
Excessive current due to
overloads.
Short circuits
(less than 0.4-ohm)
Temperature rise of heat
sin
(more than 105°C)
DC drift
Protection
Current limiter activates at
less than 2 ohm.
Current limiter activates,
input signal is lowered,
unit shuts down.
Input signal is lowered.
Unit shuts down.
Input signal is lowered.
Unit shuts down.
Indication
Compressor
LED illuminates.
Amp protection
LED illuminates.
Amp protection
LED illuminates.
Amp protection
LED illuminates.
Action
Remove excessive loads.
Minimum spea er loads
4 ohm.
Chec spea er
lines/systems for shorts.
Chec for adequate
ventilation.
Refer to qualified service
personnel.
Restoration
Automatic restoration
after normal loads are
obtained.
Turn off power switch.
Turn on into operational
loads.
Automatic restoration
after temperature
lowers (to 75° - 95° C)
Automatic restoration
after normal bias is
regained.
— 4 —
Rear anel

MAIN S EAKER SYSTEM
S EAKER SYSTEM
for foldbac
(Self powered spea ers)
From Spea er Jac
on Rear Panel
Low Z input should be connected
with low impedance (50 ohm ~ 600 ohm)
microphones
Line Out
KEYBOARD
CASSETTE TA E DECK
for playbac
Line Out
MUSICAL INSTRUMENT
— 5 —
Connection Examples

Generally spea ing, there are two rules to follow when connecting equipment outputs
to the inputs of other equipment.
1. Properly match the impedances of the outputs and inputs.
2. Connect low impedance outputs to high impedance inputs.
It goes without saying that not only input and output impedance matching, but also
level matching should be ta en into consideration. Each input channel of the MX-401
is provided with an Input Level Control that includes a negative feedbac (NF)
circuitry, so the usable signal level range is wide. Input impedances and levels are
shown in the following table.
IN UT S ECIFICATIONS
*Sensitivity is the level required to produce a program out level of +4dB.
*0dB is referenced to 0.775V RMS.
All XLR Type connectors are electronic balanced. Phone jac is unbalanced.
If the line going from one piece of equipment to another is long (more than 5m), we
recommend that balanced outputs be connected to balanced inputs.
As is described in the beginning of the Operating Instructions Manual, the connectors
of the MX-401 are wired as follows: Pin 1 is ground (shield). Pin 2 is cold (low, minus).
Pin 3 is hot (high, plus).
— 6 —
CONNECTION
CH1
CH4
AUX
GEQ
PWR/AMP
INPUT
LOW Z
HIGH Z
ACTUAL
LOAD
IMPEDANCE
OPEN
27
30
50
10
FOR USE
WITH
NOMINAL
50 TO 250
MICRO-
PHONES
27
OR
LOWER IMP
LINES
30
OR
LOWER IMP,
LINES
50
OR
LOWER IMP,
LINES
10 OR
LOWER IMP,
LINES
SENSITIVITY*
(PGM OUTPUT
LEVEL +4dB)
-60dB (0.78mV)
-35dB (13.8mV)
-20dB (77.5mV)
+4dB (1.23V)
+4dB (1.23V)
CONNECTOR
XLR TYPE NC3F
PHONE JACK
RCA PIN JACK
PHONE JACK
PHONE JACK
PHONE JACK
Input Connections

BLOCK DIAGRAMS
LEVEL DIAGRAM
— 7 —
Block and Level Diagrams

MIXER SECTION
Frequency Response
+0, -3dB 60Hz~20 Hz (input LEVEL at "5" position)
Total Harmonic Distortion
0.05% +4dB* at 1 Hz.
Hum and Noise (Open)
Equivalent Input Noise -130dB* (20Hz ~ 20 Hz)
Equivalent Input Noise -133dB* (IHF A)
All
level Controls Minimum -110dB* (IHF A)
PGM Master at MAX and all
input level controls minimum -90dB* (IHF A)
PGM Master at MAX and one
input level control at MAX -70dB* (IHF A)
Maximum Voltage Gain
INPUT to PGM out 64dB
INPUT to FB out 64dB
INPUT to GEQ out 64dB
AUX to PGM out 24dB
Input EQ
50Hz ±15dB Shelving
20 Hz ±15dB Shelving
Equalization
63Hz ±12dB Pea ing 2 Hz ±12dB Pea ing
250 Hz ±12dB Pea ing 8 Hz ±12dB Pea ing
1 Hz ±12dB Pea ing
IN UT S ECIFICATIONS
OUT UT S ECIFICATIONS
OWER AM LIFIER SECTION
Frequency Response
+0, -1dB 15Hz to 30 Hz (150W RMS 4
Rated ower & Load
150W RMS (4 ) 110W RMS (8
ower Output at Clipping
1% THD, 1 Hz
160W RMS (4
) 115 W RMS (
Total Harmonic Distortion
Less than 0.1% (200mW ~150W RMS, 20Hz~20 Hz, 4
Typically below 0.05%
Compresser Dynamic Range
Greater than 26dB
Hum and Noise
At least 105dB S/N ra t i o , 20Hz~20 Hz
At least 109dB S/N ra t i o IHF-A weighted
Damping Factor
Greater than 200 [1 Hz 8
Input Sensitivity
+4dB* (1.23V)
Input Impedance
10
Output Connector
Phone Jac ×2
ower Requirement
300W
Dimensions
494(W) × 180(H) × 304(D) (19.44 × 7.09 × 11.97) ins.
Weight
10 g (22 lbs)
*0dB is referenced to 0.775V RMS.
*Specifications are subject to change without notice.
)
)
)
)
CONNECTION
CH1
CH4
AUX
GEQ
PWR/AMP
INPUT
LOW Z
HIGH Z
ACTUAL
LOAD
IMPEDANCE
OPEN
27
30
50
10
FOR USE
WITH
NOMINAL
50
TO 250
MICRO-
PHONES
27
OR
LOWER IMP
LINES
30
OR
LOWER IMP,
LINES
50
OR
LOWER IMP,.
LINES
10 OR
LOWER IMP,
LINES
SENSITIVITY*
(PGM OUTPUT
LEVEL +4dB)
-60dB (0.78mV)
-35dB (13.8mV)
-20dB (77.5mV)
+4dB (1.23V)
+4dB (1.23V)
CONNECTOR
XLR TYPE NC3F
PHONE JACK
RCA PI N JACK
PHONE JACK
PHONE JACK
PHONE JACK
CONNECTION
PGM
GEQ
FB
ACTUAL
SOURCE
IMPEDANCE
600
600
600
FOR USE WITH
NOMINAL
600!
OR HIGHER
IMP. LINES
600
OR HIGHER
IMP. LINES
600
OR HIGHER
IMP. LINES
OUTPUT LEVEL*
NOMINAL
+4dB (1.23V)
+4dB (1.23V)
+4dB (1.23V)
MAX. BEFORE
CLIP
+20dB (7.75V)
+20dB (7.75V)
+20dB (7.75V)
CONNECTOR
PHONE JACK
PHONE JACK
PHONE JACK
Specifications

LOW Z HIGH Z IN & IN UT EQ (LEVEL Control)
HIGH Z IN. & IN UT EQ (set at "5")
OWER AM OWER BAND WIDTH
OWER AM COM RESSOR
GEQ
OWER AM T.H.D. vs OWER OUT UT
REVERBERATION FREQUENCY RES ONSE
304 (11.97")
494 (19.44")
180
(7.09")
— 9 —
Characteristics Diagrams
Appearance

Toa Electric Co., Ltd.
KOBE, APAN
Printed in apan
133-02-873-5