High Equalizer Control
(HIGH)
The high EQ control alters t h e
high frequency response of the
input channel, providing ±13dB
at 10kHz, and ±15dB at 20kHz 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 f l a t audio response.
Reverb to Foldback
Control (REV TO FB)
This control adjusts the amount
of reverb signal t h a t is returned
to the foldback buss and t h u s t h e
level of reverb contained in t h e
on-stage monitor mix.
Reverb/Control
(REV)
This control determines t h e
level of signal assigned to the re-
verb mixing buss. R o t a t i n g t h e
control clockwise increases the
amount of reverb in that channel.
Foldback Control (FB)
The Foldback
control deter-
mines the level of signal assign-
ed to the foldback mixing buss,
t h u s s e t t i n g the level of t h a t
channel in t h e on-stage m o n i t o r
mix.
Graphic Equalizer
(EQUALIZATION)
The graphic equalizer is 5 inde-
pendent active bands ( f i l t e r s ) ,
p r o v i d i n g 12dB of boost or cut at
each center f r e q u e n c y . The "0"
detented p o s i t i o n provides f l a t
audio response.
Foldback Master Control (FB)
The FB master control a d j u s t s
the overall combined signal level
of the four independent channel
foldback sends, and thus the
level of the e n t i r e on-stage moni-
tor mix.
Aux Level Control (AUX)
This control sets the overall level
of t h e Aux i n p u t signal.
Power Amp Compression
Indicator
(COMP)
The Comp LED l i g h t s when the
internal compressor is activated.
The compressor is provided to
protect speaker systems by com-
pressing t h e i n p u t signal level of
the power amplifier when clip-
ping occurs in the o u t p u t stage.
Frequent flashing of the LED is
not reason for alarm. However, a
constant or steady light indicates
t h a t the MX-401 is being over-
driven and t h a t the internal
power
amplifier is possibly
"under powered" for that applica-
tion. The o u t p u t level of the MX-
401 should be decreased u n t i l the
LED only flashes i n t e r m i t t e n t l y .
Power Indicator LED
(POWER)
The i n d i c a t o r LED l i g h t s when
t h e power s w i t c h is "on".
Input Level Control
(LEVEL)
The level control provides con-
t i n u o u s l y variable a d j u s t m e n t
of the channel o u t p u t to the
program
mixing buss,
t h u s
determining the level of t h a t
channel in t h e main sound
system mix. Since t h e r e v e r b
signal is "post" this c o n t r o l , an
increase in t h e level of the
channel's o u t p u t will also result
in a corresponding increase in
the reverb effect of t h a t channel.
The nominal level of t h e i n p u t
level control is at t h e "10" posi-
tion.
High Impedance Connectors
(HIGH Z)
These connectors are unbal-
anced, standard 1/4" phone j a c ks
with an input impedance of 27k
ohms, and an input level of
—35dB. When a plug is inserted
into the high -Z i n p u t , 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 1k ohms.
Reverb to Program Control
(REV TO PGM)
This control a d j u s t s the a m o u n t
of reverb signal t h a t is r e t u r n e d
to t h e program buss and t h u s the
level of reverb contained in t h e
main sound system.
Program Master Control
(PGM)
The PGM control a d j u s t s t h e
overall combined signal level of
t h e f o u r independent c h a n n e l
level controls, and t h u s the level
of t h e main sound system.
Aux Input Jacks
(AUX IN)
The phone j a c k and RCA pin
j a c k s are wired in parallel, w i t h
an i n p u t level of —20dB. When a
plug is inserted i n t o t h e phone
j a c k , the RCA pin jacks are
a u t o m a t i c a l l y s w i t c h e d out of
the AUX circuitry.
Foldback Output Jack
(FB OUT)
This j a c k is for c o n n e c t i o n to
external power a m p l i f i e r s and/
or equalizers for the on-stage
m o n i t o r i n g system. N o m i n a l
o u t p u t level is +4dB w i t h an
impedance of 600 ohms. If t h e
internal power amp and equal-
izer are to be used for t h e on-
stage m o n i t o r system, the FB
o u t p u t should be connected t o
t h e GEQ i n p u t j a c k .
Program Output Jack
(PGM OUT)
The PGM Out j a c k is provided
for c o n n e c t i o n t o e x t e r n a l e q u a l -
izers a n d / o r power amps, d e r i v -
ing i t s signal prior to t h e i n t e r n a l
GEQ and power amp. N o m i n a l
o u t p u t level is +4dB w i t h an
impedance of 600 ohms.
Graphic Equalizer Input Jack
(GEQ IN)
The GEQ i n p u t jack allows t h e
g r a p h i c e q u a l i z e r to be used in-
d e p e n d e n t l y of t h e
MX-401
w i t h
other e x t e r n a l e q u i p m e n t , or t h e
i n t e r n a l power a m p l i f i e r and t h e
graphic equalizer w i t h e x t e r n a l
e q u i p m e n t . When a plug is
inserted, t h e main mix f r o m
t h e p r o g r a m buss is d i s c o n n e c t e d
f r o m t h e graphic e q u a l i z e r and
t h e power a m p l i f i e r . The nomi-
nal i n p u t level is +4dB w i t h an
i n p u t impedance of 50k ohms.
Graphic Equalizer Output Jack
(GEQ OUT)
This j a c k allows t h e
MX-401
and t h e i n t e r n a l g r a p h i c e q u a l -
izer t o be used w i t h an e x t e r n a l
p o w e r a m p l i f i e r , or in c o n j u n c -
t i o n w i t h t h e GEQ in j a c k , t o be
used i n d e p e n d e n t l y of a l l o t h e r
MX-401
c i r c u i t r y .
N o m i n a l
o u t p u t l e v e l is +4dB w i t h an
i m p e d a n c e of 600 o h m s .
Power Amp Protection
Indicator (PROTECT)
The i n d i c a t o r LED lights if t h e
power a m p l i f i e r o u t p u t is s h o r t -
ed, if t h e t e m p e r a t u r e of the u n i t
rises above acceptable levels, or
if DC is d r i f t e d to t h e speaker
o u t p u t s . I f t h e LED should l i g h t ,
speaker w i r i n g and a m b i e n t
t e m p e r a t u r e of t h e
MX-401
should be checked. If t h e LED
remains l i g h t e d , t h e u n i t should
be referred to q u a l i f i e d service
personnel for repair.
Note:
The
MX-401
p r o t e c t i o n c i r c u i t r y
will (1) detect ' f a u l t y conditions'
w i t h i n t h e power a m p l i f i e r , (2)
give a v i s u a l i n d i c a t i o n , and (3)
a u t o m a t i c a l l y s h u t down u n t i l
t h e f a u l t c o n d i t i o n is alleviated.
This special c i r c u i t r y ensures
m a x i m u m r e l i a b i l i t y and vir-
t u a l l y
e l i m i n a t e s
e q u i p m e n t
damage due to u n s a f e or f a u l t
c o n d i t i o n s . Please r e f e r to f a u l t
p r o t e c t i o n t a b l e on page 4 for
f u l l
e x p l a n a t i o n of t h i s im-
p o r t a n t f e a t u r e .
Power Amplifier Input Jack
(PWR IN)
The PWR Amp i n p u t jack allows
t h e i n t e r n a l power a m p l i f i e r to
be used w i t h e x t e r n a l e q u i p -
m e n t . When a plug is i n s e r t e d ,
t h e p o w e r amp is a u t o m a t i c a l l y
d i s c o n n e c t e d f r o m t h e
MX-401
m i x e r s e c t i o n . The n o m i n a l in-
p u t l e v e l is +4dB w i t h an i n p u t
i m p e d a n c e of 10k ohms.
— 3
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Front Panel
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