MCi JH-500 Series User manual

PROFESSIONAL
MIXING DESK

The JH-528 PROFESSIONAL AUDIO MIXING CONSOLE has been
designed to be the most efficient and the most flexible
console available. It is styled in an oil-finished solid
oak with control panels in a natural sugar maple color.
The large padded arm rest is covered with genuine English
leather.
The entire console has been built small enough so that
the average person can reach most of the controls without
moving. Yet the profile is low, creating minimum control
room acoustic problems and permitting a clear view into
the studio.
This console was designed for maximum f l exibility and for
easy conversion to AUTOMATED CONTROL . Each channel has a
VOLTAGE CONTROLLED AMP LIFIE R for the le ve l control function.
The FADER uses a 4 inch conductive plastic element . This
circuit is AUTOMAT ION - READY . In addition, the QUAD PAN
controls and the level controls for two SEND BUSSES are
AUTOMATION - CAPABLE .
Tell us what you would like to do in your studio, and the
chances are that we wil l show you ~~ can be accomplished
with this console. The following pages show some of its
capabilities.

INPUT/OUTPUT MODULES
A seperate INPUT/OUTPUT module is provided for each MIKE
input or TAPE RETURN input. Each of these modu l es contain
all of the circuitry, t he switching, and the controls for
the fo ll owing functions :
MIKE PREAMP
BUSS AMP
t--C>=~
0---0
CHANNEL BUSSING SW
LINE IN
MIKE/
LINE
LINE OUT
MIKE/LINE
PROGRAM
MON
TO BUSS CHANNEL
ACN
~
>-....---<~
QUAD
POST PAN §
AMP
QUAD
MIX
METER BUFFER
INDIVIDUAL SEND BUSSES
PREAMP ~~ ____ __________________________ ~
•
PRE/POST
SEND OUT
Each MIKE INPUT is provided with 32 OUTPUT BUSS SE LECTOR
switches. Any mike can be assigned to ANY COMBINATION of
OUTPUT CHANNELS .
A
CHANNEL MIKE/LINE switch permits PING-PONGING tracks by
connecting the Channel switching to LINE RETURN(WITHOUT
AFFECTING MONITORING CAPABILITY).
A PAN CON TR OL for the ODD-EVEN BUSSES is provided.
An LED beside each Channel switch indicates Channel
assignment(s) .

EQUALI ZA TI m~
Four basic adjustment areas are provided which together provide
for over 140 MILLION COMBINATIONS. Discrete switching is used
so that you can always return to any exact combination.
The EQ Filter frequencies are interrelated MUSICALLY (1 / 2 oc ta ve
range s ) so that they relate directly to the music you are
recording.
LOW FREQUENCY EQ
A Low Frequency Shelf can be switched to any of the following
frequencies:
30 Hz
60 Hz
HIGH FREQUENCY EQ
100 Hz
150 Hz
The adjustable gain for this
circuit is flO dB in 2 dB
discrete steps.
Either a High Frequency Shelf or a High Frequency Peaking
circuit is provided (Swi tchab1 e) • These circuits may be switched
to any of the following frequencies:
8 kHz
10 kHz
MID RANGE NUMBER 1 EQ
12 kHz
16 kHz
The adjustabl e gain for this
circuit is flO dB in 2 dB
discrete steps.
You may switch in a BOOST ora CUT circuit at any of the 1/2
octave frequencies between 150 Hz and 7.5 kHz:
150 Hz
200 Hz
300 Hz
400 Hz
600 Hz
900 Hz
1.2 kHz
1.8 kHz
MID RANGE NUMBER 2 EQ
2.5 kHz
3.5 kHz
5.0 kHz
7.5 kHz
The adjustable gain for this
circuit is ±14 dB in 2 dB
discrete steps.
You may switch in a BOOST or a CUT circuit at any of the 1/2
octave frequencies between 180 Hz and 8.5 kHz:
180 Hz
250 Hz
350 Hz
500 Hz
750 Hz
1.2 kHz
1.5 kHz
2.2 kHz
3.0 kHz
4.3 kHz
6.0 kHz
8.5 kHz
The adjustable gain for this
circuit is ±14 dB in 2 dB
discrete steps.

HIGH PASS FILTER
A HIGH PASS FILTER has been provided which is independent of the
other EQ circuits. It is tunable between 30 Hz and 300 Hz and
has a slope of 24 dB per octave. This circuit may be switched
out if desired.
EQ SWITCHING
An EQ IN/OUT switch is provided to permit bypassing all
equalization if pesired.
A movable PATCH POINT is provided to permit the compression
or limiting to be connected either before or after EQ.
An
EQ MONITOR/CHANNEL switch is provided to permit the EQ to
be placed either in the MIKE circuit for equalizing the
signal to the MASTER TAPE, or in the MONITOR circuit for
equalizing the RETURN signal •
- ~ ,
........ • ••.1 I ~ I . I •• ................
JH-500 SERIES I/O MODULE

LEVEL CONTROLS
There are two main LEVEL CONTROL . circuits for each channel.
One circuit is a conventional audio amplifier with a 45 mm.
conductive plastic linear fader. This circuit is normally
assigned to the MON ITOR circuit. The second LEVEL CO NTRO L
circuit is a VO LTAGE CONTROLLED AMP LIFIE R w hich uses a linear
4 inch conductive plastic fader. This combina~ion is normal-
ly assigned to the CHANNEL OUTPUT.
The MASTER PROGRAMMING for these level controls is provided
by the FDR button located on the STUDIO MONITOR module. Whe n
this button is depressed, the program for these two controls
on ALL channels is REVERSED. The VCA is switched to the
MON ITOR channel and the MONITOR LEVEL CONTROL circuit is
switched to the CHANNEL OUTPUT.
An FDR REV button is provided on each INPUT/OUTPUT module to
REVERSE THE PROGRAMMING (f or that module only) .
A GREEN LED beside the VCA FADER lights whenever the VCA
circuit has been changed to the MONITOR circuit.
Level controls for the eight SUB GROUPS described in the
MONITORING SYSTEM section are located as follows:
2 e ach in the 3 AUXILIARY modules
2 in the STUDIO MONITOR module.
LOCAL FADER SWITCHES associated with each of these SUB GROUP
FADERS removes control of that SUB GROUP from the MASTER FADER
(lo cated on the MASTER module) . Thi s allows as many as NINE MASTER
FADERS to be created. Each S UB GROUP will ha ve its own MASTER
FADER, and the channels NOT assigned to a SUB GROUP or to the
MASTER FADER will be controlled by their in d i vidua l ch an ne l
faders.
This block diagram shows the interconnections between the
amplifiers which feed the control voltages to the VCAs.
fixed DC
level
master
fader
MASTER
MODULE
fixed
DC~
l evel
I
I
local
group~· .. --t
fader
INDIVIDUAL GROUP
I M
fixed DC
levell~
I I 0
I
2
3 0
channel
fader
CHANNEL
LEVEL
CONTROL
INPUT/OUTPUT MO DULE

An LED is mounted close to each VCA FADER in the system.
This LED lights if the control voltage is at a maximum.
THIS IS NOT A DISTORTION INDICATION. It mereZy indicates
th at the-cTrcuit is at maximum gain.
MONITORING SYSTEM
Eac h INPUT/OU TPUT module has full QUAD PANNING capability.
Two seperate potentiometers are provided, one for LEFT- RIGHT
and one for FRO NT-BACK. These controls are AUTOMATION - CAPABLE .
The MAS TER module ' provides a + IOdb gain control in I Db
discrete steps for all QUAD and STEREO outputs. a pot e nti o-
meter provides a trim for MONO output.
A CALIBRATE bu t ton is provided which over r ides MONO trim,
STEREO trims, and QU AD trims. This button returns the
mo nit or in g system to calibrated l evels .
Each INPUT /O UTPUT module has 6 SEND LEVEL CONTROLS which feed
6 SEND BUSSES. These busses can be used for ECHO SENDS or
for CUE SENDS.
Each of the 6 SEND BUSSES can be selected from a POST-FADER
or a PRE-FADER point.
SENDS I and 2 are controlled by 45rnrn. conductive plastic
linear faders and are AUTO MAT ION-CAPABLE .
SENDS 3 and 4 have individual level controls.
SENDS 5 and 6 are controlled by a singl e level control
follo wed by a Pan Pot between the two busses.
A MASTER trim pot for each indi v idual SEND is located on the
CO N TROL ROOM MONITOR module.
A"WET" switch changes the PRE-( fader) position of SENDS 3 and
4 to CHA NN EL BUSS OUT position. TH I S IS THE ROUTING USED TO
F EED AN ECHO CHAMBER WHEN RECORDING ECHO ON THE MASTER TAPE .
The ECHO RETURN SYSTEMS are described elsewhere in this book .
A
MON ITOR INPUT PROGRAMMING switch is provided on the STUDIO
MONITOR module. This button programs all INPUT /O UTPUT module
monit o ring contr o ls to either CONSOLE LINE INPUT (tape return)
or C ON SO LE LINE OUTPUT.
Each INPUT /O UTPUT module has a MONIT OR OVERRIDE button which
re vers es the control of the MONITOR INPUT P ROGRAMM I NG switch
(F OR THAT CHANNEL ONLY) .
A MON to BUSS switch per mits using A LL 32 BUSS OUTS as add iti onal
sends dur in g mixdown.

CONTROL ROOM MONITOR
SWITCHING
CONTROL MONITOR SELECTOR switches permit the monitoring of:
Three 2-track tape machines, two 4-track tape machines, the 6 ~ND BUSSES,
the t wo stereo CUE systems, and th e 2-m ix , 4-mix syste ms.
The QUAD CONTROL Meters will follow these selections automati-
cally, but the metering level is NOT affected by the monitor
level. When the MONO position is selected, the monitors are
switched to a MONO output, but the meters will still follow
the QUAD of the STEREO output.
4 individual MONITOR MUTE switches are provided.
The rear monitors are automat~cally muted when a stereo input
is selected. When changing between Quad and Stereo, an auto-
matic level adjustment circuit keeps the level constant.
An ALTERNATE SPEAKER switch provides a command to switch to
and alternate set of control room speakers.
An ALTERNA'!'E CENTER switch permits shifting the "center of the
room" from the C. ONSOLE to the PRODUCER's DESK. Internal pots
are provided to set up this "alternate center" location. A
warning lamp is turned ON when this button is depressed.
When e ither the SLATE, the TALKBACK, or the COMMUNICATION
system is activated, control room monitor dimming is
automatically provided.
LEVEL CONTROLS
Individual switches provide a ~ 5 Db trim in I Db discrete
steps to each of the four CONTROL ROOM MONITORS.
A SOLO trim pot provides 20 Db of gain control when a MONO
SOLO is being monitored.
The MASTER CONTROL ROOM LEVEL CONTROL is capable of adjusting
the monitor level from + 6 Db to - infinity.
SEND OUTPUT CONTROLS
The 6 SEND OUTPUTS are located on the CONTROL ROOM module.
Each SEND is provided with a MASTER LEVEL TRIM and has switch-
able HIGH PASS and LOW PASS filters. These filters are variable
between -10 dB and +10 dB. The 3 dB points are at 60 Hz and
at 10 kHz respectively.

STUDIO MONITOR
SWITCHING
STUDIO MONITOR SELECTOR switches permit the monitoring of:
three 2-track tape machines, two 4-track tape machines, the 6 SEND BUSSE S,
the 2 Stereo CUE SYSTEMS, and th e 2 -mi x , 4-mi x o ut p ut s .
The STUDIO MONITOR normally monitors in STEREO, but buttons
are provided on the STUDIO MONITOR module to select either
MONO or QUAD.
A STUDIO MUTE switch is provided to insure positive monitor
kill.
The MASTER STUDIO LEVEL CONTROL is capable of adjusting the
monitor level from + 6 Db to - infinity.
CUE I NG SYSTH1S
Two STEREO CUEING SYSTEMS are provided. These systems may be
fed from any of the following sources: The STEREO MIX busses,
SENDS (1-2), (3-4), (5-6), The ECHO RETURN circuits, or an external
Stereo signal through the patch panel.
ECHO RETURN SYSTEMS
Four ECHO RETURN systems are provided, each with full QUAD
PANNING. Two of these circuits are in the MASTER module and
two are in the COMMUNICATIONS module. One of the circuits in
each module can be switched into any combination of CHANNEL
BUSSES. (32 pu sh butt ons ar e provi de d) All four of the systems are
returned to the QUAD MIX BUSSES.
A PAN switch is provided for the two ECHO RETURN circuits which
have switching capability. This switch allows panning between
the ODD and the EVEN NUMBERED channels as a function of the
LEFT-RIGHT PAN pot. FRONT-BACK panning will not affect the
CHANNEL OUTPUT BUSSES.
Two switches provided for each ECHO RETURN allow connection of
that return circuit to CUE I and/or CUE 2 busses through the
LEFT-RIGHT pan pot.
All ECHO RETURN levels may be assigned to the MASTER FADER or
to a GROUP FADER through the SUB GROUP SELECTOR switches
provided.

MUT I NG SYSTEf1S
Muting of a single CHANNEL or of an ECHO RETURN channel may
be accomplished in six different ways. Two additional methods
are provided for muting the QUAD M IX. If ANY ONE of these
systems is activated, the CHANNEL (or ECH O RETURN) w ill be
MUTED. The OVERALL FUNCTION operates like t wo OR GATES as
shown in the following sketch:
Channel MUTE swi tch _________ ----.
Channel FADER OFF-:~_:~~::~~~~~~~
GROUP MUTE if assigned to a group
MASTER MUTE i f ass igned to MASTE R __ -,
o
~ auto mute sw.
AUTO MUTE BUSS 0 ~~
1-_1
READ OR UPDATE from Automation_
...J
MONITOR MUTE
ALL
OU TPUTS
,------ EXCEPT
QUA D
MIX
QUAD
OR GATE }--- MIX
All channels except SO LO channel ______ -{
whe n QUA D-IN-PLAC E SOLO is in use '----~
GROUP MU TING is accomplished in four different ways. The
OVERALL FUNCTION operates like an OR GATE as sho wn in the
following sketch:
GROUP M UTE _________________________ ,
GROUP FADER OFF:::;- _____________ ~ ___ ~
---------~o
~ l o cal fader sw. __ -I
MAS TE R MU TE LI NE o
o
~ auto mute sw.
AUTO MUTE SYSTEM?
ALL
OUTPUTS
>---+- AND
BUS S ES

SOLO SYSTEMS
Three SOLO buttons are provided on each INPUT/OUTPUT module
the SOLO button located near the EQ controls provides a MONO
SOLO of the INPUT to the EQ.
The SOLO button located near the CHANNEL BUSS assignment
switches provide a MONO SOLO of the CHANNEL OUTPUT.
The SOLO button located near the MONITOR level control is
programmed by the QUAD SOLO button on the CONTROL ROOM
MONITOR module. When the QUAD SOLO button is not depressed,
the MONITOR SOLO button on each INPUT /O UTPUT module wi ll
produce a MONO SOLO of the monitor output of that channel.
When the QUAD SOLO button is depressed , the MONITOR SOLO
button w ill produce a QUAD -IN-PLACE with ECHO SOLO from its
channel. ALL OTHER CHANNELS ARE MUTED. A QUAD SOLO TRIM pot.
is loca ted on the Mas ter Module. (QUAD MIX is d est royed whil e the
QUAD SOLO button is depressed.) A yellow LED on each I/O module
lights when anyone of the three SOLO buttons is used.
A SOLO button associated with each ECHO RETURN circuit is
provided w hich functions exactly like the MONITOR SOLO button
on the INPUT/OUTPUT module.
COMMUNICATIONS SYSTEMS
There are three communications systems located on the COMMU-
NICATIONS module. Each system has its own level control and
its own OFF/ON switch. Control room monitors are automatical-
ly dimmed when either of these systems is turned ON.
SLATE- When this system is turned ON, the local oscillator is
automatically switched ON and adjusted to 20Hz at -18 Db.
This signal is summed with the talkbac k mike ( Zo cated in the
consoZe) , and is fed to the selector switches marked MIX and
TKS. These switches route the signal to either the MIX
BUSSES or to the CHANNEL OUTPUT (TKS SWITCH).
TALKBACK- When this system is switched ON, the talkback mike is
connected to the STUDIO MONITOR SYSTEM.
COMM- When this system is switched ON, the talkback Mike is
connected to the SEND BUSSES through the SEND SE LE CT switches.
These switches select the SEND BUSSES in pairs (1-2), (3-4),
or (5-6).
v-]hen the COMM system is ON, the talkback mike is ALWAYS
connected to both CUE systems .

LOCAL OSCILLATOR SYSTEf1
The local oscillator is a self-leveling W einbridge oscillator
w ith a freq. range continuously variable f rom 20Hz to 20KHz.
Depressing either the X10, the X100, or the X1000 button w ill
turn the oscillator ON and set the range. The OSC FREQ kncb
varies the frequency through each range.
The OSC LEVEL controls the output from + 12 Db to -50 Db.
The output of the local oscillator is always available at the
patch bay OSC O~T jack.
The output of the local oscillator is controlled by the MIX
and the TKS switches. The MIX switch routes it to the MI X
outputs, and the TKS switch routes it to the CHANNEL OUTPUTS.
Provisions have been made for using an external sweep genera -
tor or distortion measuring equipment when the local oscilla-
tor is turned OFF. The external generator is fed into the
OSC OUT jack in the patch bay and the MIX and TKS switches
will feed the externally generated signal into the system.
METERING
24 VU meters are provided and numbered to correspond to the
same numbered OUTPUT BUSSES. All meters are driven by a
buffer amplifier to eliminate the distortion caused by meter
loading on audio amplifiers. A trim pot is also included for
exact meter calibration.
The four large central meters numbered 1, 2, 3, 4 always show
the CONTROL ROOM MONITOR OUTPUT. The meters reflect the BUSS
LEVEL ONLY, they are NOT controlled by MONITOR LEVEL CONTROLS.
The two large VU meters marked L & R in the central cluster
are switched by the ten push buttons located on the STUDIO
MONITOR module. The meters will then monitor these functions;
AUX
1-2
3-4
5-6
MONO
2MIX
F4MIX
R4MIX
CUE 1
CUE 2
Any e xt e rnal fun c ti on co nn ec t ed t o th e A UX input.
SEND BUS SES 1& 2
SEND BU SSES 3 &4
SEND BUS SES 5 &6
MONO output
STEREO o utput
FRO NT pa ir of 4 MIX output
REAR pair o f 4 MI X o utput
STEREO C UE s yst em 1
STEREO CUE s ys t em 2

PLASMA DISPLAY
An optional AUDIO METERING SYSTEM is available for use with
the JH-SOO Series Mixing Desk. The PLASMA DISPLAY uses a one-
hundred segment NEON GLOW TUBE to produce a lighted BAR GRAPH.
Cardinal scale markings on the Bar Graph are shown by brighter
bars produced by PROMs (Programmable Read Only Memo r ies) in a dif-
ferent pattern for each mode of operation. Each Bar Graph is
scanned (refreshed) over 80 times per second for a highly read-
able, flicker-free display.
There are two PRIMARY modes of operation,
In addition, the "Accumulate" mode can be
the two Primary modes.
"VU" and "PEAK".
added to either Of
The VU mode shows the Audio Level on a Display which uses a
conventional VU (logarithmic) scale.
The PEAK mode displays the Peak Audio Voltage ratio as dB
units on a linear scale. Increments of 1/2 dB are shown on
a range from -46 dB to +6 dB.
The ACCUMULATE mode is displayed as an additional reading
which appears above the normal "Transient" Audio Display.
This mode provides a "MEMORY" for the HIGHEST AUDIO PEAK
which occurs on each channel during the time it is operating.
The ACCUMULATE reading is shown as a lower intensity graph
above the TRANSIENT AUDIO reading.
As soon as a new Audio Level occurs which is higher than the
one in memory, the circuit shifts to the new, higher reading.
The value of the scale units . is the same as the Primary mode
being used. (VU units when used with Vu mode, Voltage Ratio in dB
when used with PEAK mode).
Single channel ACCUMULATE readings may be cancelled and reset
by a button under each Display. A master circuit is provided
to cancel and reset all displays simultaneously.
Softly-glowing LUMINESCENT PANELS are a standard feature with
the Plasma Display. They are both beautiful and useful. In
addition to identifying the Display mode, they light up to
show the modes of operation being used in the Console. You
are reminded by a glowing panel:
That the inputs are coming from the LINE - or from TAPE.
That the CHANNEL OUTPUT BUSSES are being fed - or that
th e MONITORS are activated .
That the VCAs are at maximum gain - or that a SOLO has
been activated.
That the DISPLAYS are switched to VU mode - or to PEAK
mode.

PATCH BAY
The Patch Bay is organized into 16 rows of 28 miniature telephone
jacks. These are Normalized Pairs where applicable.
The following is a list of the jacks supplied in the standard
Desk. The numbers in parentheses following the Title is the
number of jacks supplied under that Title.
ROW TITLE (S)
1
PREAMP OUT (28)
2 PREAMP RETURN (28)
3 PRE/POST E
QUAL I ZER IN
(28)
4 PRE/POST
EQUALI Z ER OUT (28)
5 CHANNEL LINE OUTPUT (28)
6 TAPE MACHINE INPUT (28)
7
TAPE MACHINE RETURN (28)
8 CHANNEL LINE INPU T (28)
(Whether Pre EO or Post EQ depends on
position of switch on I/O Module.)
(Whether Pre EQ or Post EQ depends on
position of switch on I/O Module.)
9 QUAD MIX OUT PUT
TAPE 4 IN (4),
(4), TAPE 1 IN
TAPE 5 IN (4) ,
(2), TAPE 2 IN (2), TAPE 3 IN
CUE SENDS (2pr), SENDS (6).
(2) ,
10 2 MIX OUT (2), MONO OUT (1), OSC
TAPE 3 RET (2), TAPE 4 RET (4),
CHAMBER INPUT (6).
(1), TAPE l RET .(2), TA PE 2 RET (2),
TAPE 5 RET (4), CUE AMP IN (2pr),
---------------------------------------------------------------------------------
11 EQ (4 IN, 4 OUT), RETURN INPUT (8), CHAMBER RETURN (6pr).
---------------------------------------------------------------------------------
12
MULT 1
MULT 4
(4), TIE SWITCH, MULT 2 (4),
(4), TIE SWITCH , MULT 5 (4),
TIE SWITCH, MULT 3
CUE INPUTS ( 2pr ).
(4) , T
IE SWITCH,
---------------------------------------------------------------------------------
13 TIE LINES (28)
------------------------------------------------------ --- ------------------------
14 TIE LINES (28)
---------------------------------------------------------------------------------
15 TIE LINES (28)
---------------------------------------------------------------------------------
16 TIE LINES (28)
---------------------------------------------------------------------------------

CONSOLE I ND I CAlOR LM1PS
The groups of indicator lamps located on the meter panel show
the following general conditions and master functions:
The two lamps marked MIKE and MON show whe ther the VO LT AGE
CONTROLLED AMPLIFIER (VCA) is switched into the MIKE mode
or into the MONITOR mode. The master programming switch
for this function is located on the STU DIO MONI T OR modu le
and is marked FOR.
The t wo lamps marked IN and OUT show whe ther the MONI TO RS
are s wi tched to the LINE INPUT of to the LINE OUTPUT. The
MASTER PROGRAMMING sw itch for this function is located on
the STUDIO MONITOR module and is marked MON.
The OVRLD light shows that one or more of the VCAs are at
·maximum gain.
The four lights with voltages marked bes ide them are monitor-
ing the power supplied to th e console. When lighted, they
indicate that the supplies are in work ing order.
OPTIONS
LI NE AMPLI FI ERS
4 additional LINE AMPLIFIERS can be built into either of the
Auxiliary modules. Th ese amplifiers are similar to the Ec ho
Return Amplifiers No.3 &4.
EQ - AUX MODULE
This module is a replacement for the Auxiliary 1 module . It
provides 4 Eq, ualizers, each identical to th e Equalizer built
into an I /O module, with some additional features :
1. A switchable High Pass Filter. This is a 4th order ,
maximally flat, Butterworth High Pass Filter. Its
low frequency response is down 3 dB at 30 Hz and
progresses down at the rate of 24 dBv per octave (80 dBv
per decade) .

2. A Phase switch. The output phase of each EQ circuit
can be switched from zero to one hundred eighty degrees.
3. Each Equalizer is transformer coupled and is normalized
to have unity gain.
The transformers which couple the Input and the Output of each
of these Equalizers are located in the underbelly of the Desk.
These 8 transformers have not been previously assigned.
SPECTRA-VUE
The JH-35 Spectra-Vue module uses the Light Meters (or Vu meters)
on the JH-500 Series Audio Desk to produce a large, readable
AUDIO SPECTRUM DISPLAY. It separates a MIX or a SOLO into
eighteen 1/2 octave bands from 45 Hz to 16.5 kHz and displays
each band on a separate meter. This Spectrum Analysis is made
in "real time" - AS YOU HEAR the program on your monitor.
SPEC IFICATIONS:
INPUTS are switch selectable from 8 sources. Simultaneous
displays of any number of these inputs is possible:
1. The 4 Quad Busses.
2. The 2 Stereo Busses.
3.
2 Auxiliary sources.
(Routed through Patch Points).
In addition to the above IN~UTS, SOLO SELECT switches are
provided so that any SOLO available from the Desk may be
monitored in three ways:
1. Visually only.
2. Both Audio and Visual.
3. Audio only.
A visual AGC (Automatic Gain Control) switch is provided to monitor
the VISUAL DISPLAY LEVEL. Audio level is NOT affected.
INPUT IMPEDANCE is 10k ohms - unbalanced.
Meter signals from the JH-500 Series Audio Desk are routed
through the Spectra-Vue module so that a relay can switch a
meter to the output of each Filter circuit when the Analyzer
is in use.

CENTERBAND FREQUENCIES
of the eighteen Filter circuits are:
45 Hz 400
Hz
3.2
kHz
70
Hz 560
Hz
4.5
kHz
100 Hz 800
Hz 6.3 kHz
140 Hz 1.1
kHz
9.0
kHz
200 Hz 1.6 kHz 12.8 kHz
280 Hz 2.2 kHz 16.5 kHz
The Spectra-Vue option is completely compatible with the JH-500
Series Audio Desk. It is built into the Auxiliary module
without altering the functions of the module, and it receives
all of its power , from the standard Desk Power Supply.
AUTOMATION BY Mel
The MCI automation system for the JH-500 Series Audio Mixing
Desk will be released by late 1976. The circuitry and the
controls needed for full automation are built into the standard
Desk. Advanced design, coupled with the extreme flexibility of
this Desk allows the WRITE and UPDATE controls to be reduced to
just three simple pushbuttons per Channel for ALL FIVE AUTO-
MATED FUNCTIONS.
When CHANNEL GROUPING is used, three buttons can control the
whole group. These buttons are already built into the modules
and are labeled VCA WRITE, VCA UPDATE, and MUTE WRITE. The
buttons are momentary pushbuttons with latching circuits. An
LED located beside each button lights whenever the circuit is
active.
Two other features of this AUTOMATION SYSTEM contribute greatly
to ease of use:
1. A design breakthrough has achieved AUTOMATIC NULLING of
all automated controls. This is accomplished electronically
and results in an additional feature:
When VCA WRITE or VCA UPDATE is activated, The mechanical position
of the Fader is taken as ZERO, or NULL POINT. (Whatever that position
may be). When Updating, changes are read as differences from the
assigned ZERO POSITION.
Therefore the Faders can be used in the UPPER(and more sensitive)
portion of their range when Updating - REGARDLESS OF THE LEVEL
BEING UPDATED.

2 . When t he UPDA TE or WRITE function has been completed , yo u
may return the Fader ROUGHLY to the vicinity where the NULL
WAS ESTABLISHED (Normally around 0 dB). An EXPONENTIAL RAMP
built i nto the NU LLING c i rcuit will AUTOMATICALLY RAMP OUT
any di fference of setting.
NO SUDDEN LEVEL CHANGE WILL OCCUR .
MUTE WRITE is treated as a separate function , and may be easi l y added
either before or after writing the VCA program.
NOTE :
The MUTE FUNCTION in the MCI Desk is NOT the us ual redu ction
of VCA ga in to minimum , but is accomp li shed by shorting the
output to ground through relay contacts .
THIS ASSURES A TRUE CUT OFF OF CIRCUIT NOISE AS WELL AS
PROGRAM MATERIAL .
THE VOLTAGE CONTROLLED AMPLIFIER (VCA) AUTOMATION HA S FOUR MODES:
WRITE Th is is accomplished by pushing the VCA button and going through the
recording with the controls set as you wish them to be.
PLAYBAC K N one of the desk buttons are u se d . Going through the recording with
the a utomation activated will cause the controls to faithfully follow
whatever you have written into the program .
UPDATE T hi s function is essentially a playback with CONTROLS ACTIVATED.
RE WR IT E
NO REWRITING OF THE PROGRAM occ urs in this mode. If you wish to test
a different comb ination of control settings , use this mode. The
originally programmed control settings will be reprodu ce d. YOU CAN
ADD or SUBTRACT from any programmed co ntrol setting me rely by moving
that control .
If you decide that you like the new settings , you may THEN rewrit e
the program. pressing BOTH the VCA UPDATE and the VCA WRITE buttons
will read back the original program , update it , and write it into
memory.

MI KE PREAMP
Input i mpeda n ce
S PEe I Fie A TID NS
Without pad
With pad
1 kHz @ 0.5% THD - into 600 ohms
300 ohms
1 . 2k ohms
2 ohms
Output impeda n ce
Nominal o u tput
Maximum output
Distortion
a dB inp ut, +28 dB o utput to 600 ohms (SO Hz)
- 6 dBm
+28 dBm
.0 3% THO
IM meas ur eme nt s with 60 Hz & 6000 Hz at a 4: 1 r atio :
-4 0 dB input, a dB output .005 % 1M
. 03 % 1M
- 128 dBm
a dB i nput, +28 dB output
Equiva l ent no i se
44 dB gain
C HANNEL CIRCUIT
(TO MA STER TAPE)
Signal to noise
Better than
Input impedance to Fader
Output impedance of Channel output
Into 600 ohms @ 0.5 % TlJD (1 kHz sig n al)
@ Nominal ou tpu t
75 dB
4k
ohms
100 o hms
+4 dBm
+27 dBm
Nominal output
Maximum output
Dist or tion
Distortion
Separation
@ +24 dBm ou tpu t
Between adjacent cha nn els assig ned to adjacent
M ike i nput t o Line output
Busses (1 kHz)
(15 kHz)
.07 % 1M Ma x .
. 0 9% 1M Max .
90 dB
72 dB
Int e rnal Head Room of
Equalizer Above +4 dB
MONITOR C IR CUIT
Input impeda n ce to Fad e r
Nomi na l output
Signal to no i se
Distortion
(MIXDOWN)
Better than
@ Nomin al au tpu t
@ +24 dBm output
Maximum output Into 600 ohms @ 0.5 % THD (1 kHz si g nal)
Separation of QUAD MIX Buss es 1 kHz
M axim um F ade r att e nuati on
PAT CH PANEL
LIG HT METER OPTION
Range (SCALE)
VU
Peak
Integra tion time
VU ba ll ist i cs
Peak ba ll isti cs
Frequency response
Inpu t impedance
Ove rshoot
Display
Number of segmen t s
Controls
(FDR KILL)
528
542
l og scale
linear scale
Rise t i me
Fal l t ime (adjustable)
Resistive - unbalanced
Less than
Le n gth
Width
1 5 kHz
Better than
up to
up to
1 . Individual Peak Acc umulate ON /OFF swi tch for each meter .
2 .
Ma ster Peak Ac cum ulat e ON /OFF s wit ch for a ll meters .
3 . VU/P
eak Se l ec t (sing l e s wi tc h contained on Master c ard.)
25 dB
4k
ohms
+4 dBm
85 dBm
. 06 % 1M Max .
.08 % 1M Max.
+27 dBm
85 dB
70 dB
80 dB
50 4 Jacks
756 Jacks
Switchable from VU to Peak
+3 dB to - 20 dB
+10 dB to - 40 dB
per ASA Standards
10 ms to Full Scale
from 1 sec . to 7 . 55 se c. FS
20 Hz -20 kHz ±1/ 2 dB
10k ohms
.1 dB
127
mm (5 i nc h es)
2 . 5 4 mm ( .1 in c h es)
100 per d i sp l ay

\\1\1:\ \ \ 4007
N. E. 6th Avenue, Ft. Lauderdale, Florida 33334
Phone : [phone] Telex: 51-4362