222
SmUe@
THE
SOUND
GENERAL Power
The FP31
(ENG) electronic field production (EFP), or film production, mixer that provides the quality and features needed for remotes.
FEATURES
Inputs
w
.
Outputs
rn
rn
Copyr~ght
27A8080
OF
THE
PROFESSIONALS'~
is a portable electronic news gathering
Three transformer-coupled, 3-socket XLR-connector
inputs; each switchable to low-impedance
microphone or line level
Lo-Cut filters available at each input to reduce ex-
traneous low-frequency interference
(Phantom) simplex
microphones available at each microphone input
Built-in tone oscillator for level checks or line tests
Slate microphone with automatic gain control (AGC)
for take identification or for emergency use
Slate tone for identifying take locations during
editing
Two transformer-coupled, 3-pin XLR-connector outputs, each switchable either to low-impedance
balanced microphone or to 600-ohm balanced line
level
Tape output to feed tape recorder input or other unbalanced Aux-level input
Front and side panel stereo headphone jacks (8 to
2,000 ohms, %-inch and 3.5 mm jacks) with separate
Phones level control. Either or both jacks can drive
Aux or unbalanced line-level inputs. Four separate
sources can be driven from these two headphone
outputs.
1991,
Shure Brothers
(KG)
Inc
Or
A-B
EVANSTON, ILLINOIS 60202-3696 V.S.A.
PROFESSIONAL PRODUCTS
for
'Ondenser
HARTREY AVENUE
Controls and Indicators
Active, feedback-type input gain controls permit
direct input of high-level sources without input
tenuators
Built-in Limiter with adjustable threshold - prevents
output clipping of mixer or input overload of
amplifier, telephone line or tape recorder
LED indicator flashes with Limiter operation or to
signal overload with Limiter defeated
Professional VU meter, factory set for 0 VU
dBm, internally adjustable for other VU levels
VU lamp, stays illuminated while pushbutton is
depressed, automatic 5-second turnoff after button
is released.
Battery check function with readout on VU meter
Master gain controls level at LinelMic and Tape out-
puts as well as tone oscillator level
Phones level control adjusts output at both head-
phone jacks
.
Mixer is powered by two standard 9V alkaline batteries that also supply simplex power for condenser
microphones
w
extreme!^
minimum battery life under normal conditions
Separate 9V alkaline battery supplies A-B power for
condenser microphones; third battery is not required
A-Q power is not used
if
Spring-loaded battery compartment prevents incor-
rect insertion of batteries; batteries available for
replacement instantly when compartment door is
opened
.
Mixer can be powered from any
such as: standard belt pack, automotive electrical
system, video tape recorder. or ac power converter
Mechanical
Extremely rugged and durable construction
Very small size and light weight
Carrying case and detachable shoulder strap sup-
plied
.
A~I
input and output connectors are professional
standard types
Performance
.
Reliable Operation under
temperature and humidity
.
Extremely low noise and low RF susceptibility permits use near microwave transmitters and in strong
hum fields
Wide, flat response, extremely low distortion, and up
+
18 dBm output level provide studio-quality per-
to
formance in a portable mixer
low battery drain provides 8-hour
11
to
18
Vdc source
characteristics
wide
extremes
Pr~nted n US
H
z
1
at-
=
+4
A
G3
7
v
2
m
z
C)
3
-
X
m
a
4
2
II
(D
2
5
o
1.
Z
(D
d
V)
C)
%
3
2.
3
0
IZo
I!
!=
Q
?
0
Q
C
2
-.
0
3
=I
rn
0
x
z
-
0
D
I
0
D
-I
D
SPECIFICATIONS
Frequency Response
30 Hz to 20 kHz
Distortion
Less than
dBm, 50 Hz to 20 kHz
Noise
Less than
Common Mode Rejection
65 dB minimum at 100 Hz, -30
Inputs
19
to
Line
'Including simplex or
Tone Oscillator
Slate Tone
Slate Microphone
Outputs
Mic
Line
Tape
Phone
Phase
Gain (at 1
INPUT OUTPUT
Line
Controls
Less than
1 kHz nominal at
400 Hz, 1
Electret condenser, omnidirectional, with AGC, activated while slate button is depressed
3-pin lnput
phase with tip of phone
CHANNEL GAIN: Active, feedback type, individual
for each input; Channel 1 control pulls out to activate
tone oscillator
MASTER GAIN: Controls LinelMic and Tape outputs, and tone oscillator and slate levels
LOW-CUT FILTERS: 7 dB
dBloctave slope
PHONES LEVEL: Controls both headphone outputs
LIMITER: Controls LinelMic and Tape outputs;
dBm factory-set threshold, internally screwdriver ad-
justable down to
recovery time typical
sec, each time button is depressed
For
Any low-Z mic
input
6003
18
k0
or greater
high level input
83
to
kHz)
-10 dB 40 dB
+2 dB
0.25O/0 total harmonic distortion at +4
-
129 dBV equivalent input noise
dBV input
IMPEDANCE
6003*
10 k3 66 k3
A-B
powered, and dynamic or ribbon microphones
+4 dBm, Master at approx. 7
IMPEDANCE
Use With 1 Actual
2 k3
&
Output connectors in phase; pin 3 in
&
mini jacks
Line
+
3 dBm; 3 msec attack, 500 msec
lnput Clipping
Level
-47
to
-17 dBV
(4.5
to
141 mV)
+3
to
+33
dBV
(1.4
to
i
Output Clipping
-
34 dBV (20 mV)
minimum into
+
18 dBm
-6
+4 dBV (1.6V
rolloff at 100 Hz, -6
44V)
Level
minimum
into
6003
dBV (0.5V
47 k3
into
Max)
into
2003
1503
RMS)
RMS
+
14
SIMPLEXIDYNAMICIA-B SELECTORS: Individual
for each input, supplies 11 to 18 Vdc Simplex (phan-
tom) or 9 Vdc A-B power with lnput in MIC position;
supplies no power with Selector in DYN position (for
dynamic or ribbon microphones) or with lnput in
position
Control Interaction
Less than 1 dB with any control combination
Output Isolation
Shorting one output shall cause no more than 8 dB
level drop at 1 kHz at other output
Overload and Shorting Protection
Shorting outputs, even for prolonged periods, shall
cause no damage. Microphone inputs will not be
damaged by signals up to 3 volts.
Indicators
POWER ON: Green LED flashes at approximately
I-second repetition rate as long as power switch is
on
-
PEAKIOVERLOAD: Limiter IN
indicate onset of limiting; Limiter OUT-flashes 6 dB
below output clipping level
BATTERY CHECK: Converts VU Meter to battery
condition or circuit voltage indicator;
indicates good batteries or adequate (11 to 18 Vdc)
external power source
VU METER: Factory-set at
level internally screwdriver adjustable
VU LAMP: Illuminates meter while button is
Red LED flashes to
0 VU or higher
0 VU = +4 dBm; 0 VU
depressed; automatic shufoff 5 seconds after
release
Power
MIXER AND SIMPLEX (PHANTOM) POWER:
plied by two internal 9V standard alkaline batteries
(Duracell
Vdc supply;
tion
SIMPLEX POWER:
6200
A-B POWER: Supplied by additional 9V standard
alkaline battery
Connectors
LlNElMlC INPUTS AND OUTPUTS: 3-pin XLR type
TAPE OUT: 3.5 mm mini jack
PHONES: Stereo jacks; one standard
phone and one
12 VDC EXTERNAL POWER: Single-pin dc power
jack
Temperature Range
OPERATING:
STORAGE: -29 to +7I0C (-20 to + 160°F)
Dimensions
48.3 mm
5-5116 in.)
Net Weight (less batteries)
1 kg (2.2 Ib)
Supplied Accessories
Removable shoulder strap, carrying case
MN1604 or equivalent) or external 11 to 18
&hour battery life under normal opera-
11 to 18 Vdc nominal through
%-inch
3.5
mm mini
-
18 to + 57OC (0 to 135OF)
H
x 160 mm W x 135 mm D (1-718 x 6-5116 x
LINE
SUP-
OPERATION
LineIMic Inputs and Outputs
XLR-type 3-pin connectors, transformer-coupled ba-
2
lanced-line circuits; pins
and 3 are signal conductors;
pin 1 is ground. All XLR connectors are in phase with
one another.
Lo-Cut Filters
Activated by Inlout switch above each Channel Gain
Control to provide low-frequency
rolloff as shown in
Figure 1. Reduce undesirable low-frequency signals
such as wind noise.
FREQUENCY
IN
Hz
LO-CUT FILTER ACTION
FIGURE
1
Channel Gain Controls
Determine preamplifier gain and provide preamplifier
output attenuation. As gain is reduced, input clipping
level increases for channel. Optimum signal-to-noise
ratio occurs with Channel controlsset as high as possible (consistent with maintaining adequate control
range and input clipping level).
Tone Oscillator
Activated by pulling out Channel 1 control knob; stable
1 kHz oscillator; level determined by Master gain control. Oscillator signal appears at all outputs. When not
in use, Channel
1
control knob should be pushed in.
Slate
Depressing Slate button activates 1 -second 400
tone and turns on Slate Microphone. Omnidirectional
electret Slate Microphone remains on while button is
depressed, can be used to identify recorded segments
or as emergency field microphone. Slate Tone and
AGC'd microphone audio levels are controlled by Master Gain Control.
Master Gain Control
Determines output levels at LineJMic and Tape outputs. Also sets Tone Oscillator level when Channel
knob is pulled out, and Slate-tone and -microphone
level when Slate button is pushed.
Headphone Jacks
Two stereo phone jacks: one mini 3.5 mm (front panel)
and one 114-inch phone (side panel). Combined output, including Tone Oscillator, Slate Tone and Slate Microphone, appears at headphone jacks. Can be used
to drive up to four headphones or Aux-level recorder
or amplifier inputs. To wire either connector for two outputs, connect one conductor to tip; connect other conductor to ring; and connect
shield(s) to sleeve of appro-
priate mating stereo plug. Tip and ring of headphone
jacks in-phase with pin 3 of XLR
put connectors.
Phones Control
Sets output level at headphone jacks.
Limiter
Limiter Inlout switch turns on fast-acting, peak-responding limiter circuit to cut overload distortion during
loud program intervals without affecting normal program levels. Limiter switch In (operating) restricts
maximum mixer output to approximately +14
creasing individual Channel or Master gain controls increases both average output and amount of limiting. To
change Limiter threshold, see section on Limiter
Threshold Adjustment.
Peak
LED
Indicates Limiter operation with Limiter switch In. With
switch Out, flashes at 6dB below output clipping. Peak
indicator responds much faster than meter, activated
by even shortest transient peak, yet remains lit long
enough to provide easy recognition.
VU Meter
Factory calibrated for
load at Line output. (Microphone output levels are 50
dB below Line output.) Supplied
mended for normal use to provide approximately
headroom between operating level and clipping level.
To change
0 VU level, see section on VU Meter Adjust-
ment.
VU Lamp
Illuminates meter while button is depressed; automatically turns off 5 seconds after release to prevent bat-
tery drain.
Tape Outputs
3.5 mm jack to feed unbalanced Aux-level input of tape
recorder or amplifier. Tip of connector in phase with pin
3
of XLR connectors.
Telephone Lines
Hz
In Line position, output transformer will operate with
dc-biased "dialed up" telephone lines although there
may be slight increase in distortion. When connecting
FP31 to telephone line, use FCC-Registered* interface adapter between mixer and telephone line.
'DOC-Certified
in
Canada
Condenser Microphone Power
Condenser microphones, either
1
(simplex) powered or 9 Vdc
supplied from any Mic input of
inside battery compartment, are three 3-position
switches. Center position is for dynamic microphones
(no dc power supplied to Mic input); left position is for
9-Vdc A-B power, right position is for 11
phantom power.
NOTE: No power is supplied to any input with
switch in Line position. No
less right-side battery is present.
Mixer Powering
In ordinary portable use, the FP31 is powered by two
standard 9-Vdc alkaline batteries installed in
LineJMicinput andout-
dBm. In-
+4
dBm = 0 VU with 600-ohm
0 VU level is recom-
12
to 18 Vdc phantom
A-B(T) powered, can be
FP31. Below batteries,
-
to 18-Vdc
LineJMic
A-B
power is supplied un-
leftmost
14dB
battery compartment positions. Phantom power is also
supplied by these batteries.
The FP31 can also be powered by an 11 to 18 Vdc external source, such as an automotive battery, battery
beltpack, Shure PS20 AC Adapter or other low-ripple
ac power converter (see Figure 2), using
the1 2 Vdc
single-pin coaxial input connector in the left-side panel. To filter possible power-supply hum and noise, install a 100
resistor on the
"+"
side of the dc output.
C2
The outside barrel of the mating connector is positive.
u
*Wire with white stripe is
Cut off molded dc power plug of PS20 and wire new
as
connector
shown
12
V+
-
Coaxial
J
Plug
POWERING FP31 FROM EXTERNAL AC ADAPTER
FIGURE
2
Parts Required:
1 Shure PS20 AC Adapter or equivalent (dc output
=
12 Vdc, 100 mA minimum)
1 100
1
L2
1
W resistor
Coaxial dc power plug to fit
FP31
external
dc
power jack (2.1 or 2.5 rnm I.D.) Radio Shack
#274-1567A
Batteries can be left in place as backup in case of failure of external source. Switchover to internal batteries
is performed by disconnecting external plug.
CAUTION
12 Vdc input circuit is not fused. Any external source
should be provided with in-line fuse, 0.25 A, 250 V,
as
safety wecaution.
Battery
Check
Depressing BATT button converts VU Meter to readout
of battery condition (two mixer-powering batteries) or
of supply voltage. Readings of
0 VU or higher indicate
good batteries or adequate external supply.
VU METER ADJUSTMENT
To set the VU Meter for a value different from the
supplied
0 VU = +4 dBm, proceed as follows.
1. Connect a 600-ohm load to one of the Line outputs.
(e.g.,
HP
2. Connect an acvoltmeter
400GL) in parallel
with the load.
3.
Pull out the Channel 1 knob to activate the Tone Os-
cillator.
4.
Adjust the Tone Oscillator level with the Master gain
control until the ac voltmeter reading is at the level
desired.
5. With a screwdriver, adjust the VU Level
A-BIDYNISPLX Selector switches) until the
of the
VU Meter reads
LIMITER THRESHOLD ADJUSTMENT
0.
trimpot (left
To adjust the Limiter threshold for a value different from
the supplied
+I
4
dBm, proceed as follows.
1. Connect a 600-ohm load and an ac voltmeter to a
Line output as described in steps 1 and 2 above.
2. Pull out the Channel
1 knob to activate the Tone Os-
cillator.
3. With Limiter switch Out, adjust Master gain control
until the ac voltmeter reading is at the level desired.
4.
Move the Limiter switch In, and adjust Limiter
Threshold
trimpot (left of the VU Level trimpot) until
the level drops 0.5 dB.
FURNISHED ACCESSORIES
Carrying Case
Shoulder Strap 90BX2600
.......................
.....................
9588066
I
I
Rlc
PL7218
270-090
Commercial Alternate
Stackpole 57-0181
Stackpole 57-3425
80A250 Ferrite Bead Ring
80A365 Ferrite Bead Ring
-
-
- -
-
-
L1-L10
L201, L202
L301
None
Radio Shack
VU Meter (Special VU Range)
Cartridge, Electret
None
None
1-3
Knob, MIC
Knob, MASTER
None
None
Precision Lamp
TI, IOV, .027A
Battery Cover
Lamp,
Knob, PHONES
-
-
-
-
M P6
PLI
Motorola 2N5210
Farranti FST185L
Transistor, NPN
Transistor. NPN
-
-
Q101 RKC89
Q102, Q103,
TI593
None
TI
look, with
Potentiometer,
Transistor, PNP
I
86A335
1
-
-
S108
&
R110
(2104, Q301
Q302 RKC66
Piher PTlOLh(2.5)lOOk
None
None
lOOk
Potentiometer, lOOk
Potentiometer, 50k
Potentiometer,
SPDT Switch
I
None
Piher PTIOLh(2.5)50k
Alcoswitch MSS4200RG
Potentiometer, 50k
Potentiometer, 50k
Switch, Slide, 4PDT
I
None
Alcoswitch SLS-230PC
I
Switch, Slide, DPTT
Sw~tch, Slide, DPDT
I
55A8022
1
-
I
- -
I
SI04. S105,
Sl06
1
None
Swttch, Pushbutton, SPDT
None
I
51 D243 Transformer, Input
Raytheon RC4156N
None
Transformer, Output
1
A8015
868808 lntegrated Circuit, Quad Op
51
National Semiconductor
LM386N-4
None
Power Amplifier
lntegrated Circuit, Audio
Opto-Isolator
Ampl (Selected for NF)
I
Raytheon RC4156N
Motorola LM393N
lntegrated Circuit, Quad Op
lntegrated Circuit, Dual
Raytheon LM339DB
TI UA78LIOACLP
lntegrated Circuit, 10V
Regulator
lntegrated Circuit, Quad
comparator
U301
ved for piece parts where
Comparator
be ordered by that kit number. Orders re(
1
lipped in RKC quantities.
Parts listed as RKC Kits
Kit number is shown wi
REPLACEMENT PARTS LIST
Commercial Alternate
Panasonic ECEBOJK220
Of:
Description
I
86V628 Capacitor, Electrolytic,
Replacement Kit Consists
CIty.l Part No.
Replace.
ment Kit
EK4R7
336RSS010M
Panasonic ECEBI
22 pF, 6.3V
I I
1-1
Marcon CESSMI E4R7
Marcon CESSMlC471
pF, 16V
pF, 25V
4.7
470
86AC629 Capacitor, Electrolytic,
86AD629 Capacitor, Electrolytic,
Marcon CESSMlC471A
I.C.C.
470 pF, 16V
Capacitor, Electrolytic,
I
868629 Capacitor, Electrolytic,
1-1
--
I
Panasonic ECEBI HKO10
pF, 1ov
pF, 25V
1
33
Capacitor, Electrolytic,
Marcon CESSMIC221
I.C.C. 227RMR025M
Marcon CESSMlA470
pF, 16V
pF, 25V
Capacitor, Electrolytic,
220
Capacitor, Electrolytic,
220
Capacitor, Electrolytic,
I.C.C. 107RMR016M
pF, 16V
pF, 1ov
100
Capacitor, Electrolytic,
47
I.C.C. 226RSS016M
I.C.C. 108RMR025M
IF, 16V
1000 pF, 25V
Capacitor, Electrolytic,
Capacitor, Electrolytic,
22
TI IN4148
Diode, Silicon, Computer,
75v
RCA 1 N48, 1 N60
Diode, Germanium, 30V
Motorola IN4002
I
Silicon Rectifier. 100V. '%A
1
86A404
1
4
I
RKC21
SLR34MG3
Rohm SLR340R3
ITT Cannon XLR-3-31-F77
Rohm
Diode, Light Emitting, Green
Diode, Light Emitting, Red
Connector, Three Socket
I
ITT Cannon XLR-3-32-F77
None
None
None
3.5mm
in.
'h
Phone Jack, Miniature,
Phone Jack,
Connector, Three-Pin
Power Jack, Coaxial
RK(
red for piece parts where
by that kit number. Orders recc
d
IKC quantities.
be shipped in
ihould be order1
Reference
C102, C104,
C106
Designation
C107, C109,
C115, C119,
C126, C130,
C205, C302,
C303,C305
C112, (2120,
C153
C114, C154,
C122, C150,
C211, C154,
C212
C128
C129, C131,
C206
C133
C144
C145, C146,
C147
C148
(2149, C157,
C158, C159
C152
D101-D112,
D115, D117,
D120, D201,
D306
D202, D203
D113, D114,
D302, D303,
D304, D305
D118, 0119,
D205
'arts listed as RKC Kits
<it number is shown wi
PC
BOARDS
BOTTOM BOARD - COMPONENT SIDE BOTTOM BOARD -SOLDER SIDE
TOP BOARD - COMPONENT SIDE
METER BOARD - COMPONENT SlDE
TOP BOARD - SOLDER SIDE
.
-
METER BOARD - SOLDER SlDE
CIRCUIT DIAGRAM
r----------7
TAPE OUT
MINI
JACK
PUONE
I
I
I
I
I
I
I
I
I
JACK
RME
TMR
NOTES
ALL CAPACITORS IN p.F
1.
ELECTROLYTIC CAPACITORS
2.
ALL RESISTORS L/WI 5% LNLESS OTHERWISE SPECIFIED.
3.
FOLLOWlffi SYP(BOLS DEMTE:
;;K;S
4.
ALL
VOLTAGES
POWER INPUT CWECTOR. ALL SWITCHES IN WSITIONS SWNI EXCEPT
AS NOTED. MIC
2 AND
3
OF JLI SUPPLIED BY 150
J5)
(J4 OR
200
OHMS. INPUT L
SET FOR 0.W RHS ON WIPER (APPROXIMATELY MID POSITION). VOLTAGES
ARE MEASURED WITH RESPECT TO
AC VOLTAGES MEASLRED WITH LO
LAC VOLTAGES
5. WLTAGES SHMN FOR ULOZC
MLTAGES SHlWN FOR Urn6 OBTAINED WITH SLATE SWITCH MPRESSED.
6.
AC VOLTAGES SHOWN FOR SECTIOvS A AND B OF
ACOUSTICAL
COUPLED ILpF) L KHz, 3 mV RMS SIGNAL APPLIED AT THE JLNCTIW
RL57 AND
WITHIN
bND D OF ULW ARE BEST READ WITH R209 SHORTED
SLATE TONE TIMER FROM TIMING OUT THE SLATE TONE OSCILLATOR.
WADED WITH
OMS FROM TIP AND RING TO SLEEVE.
INPUT
R158.
6"
OF THE FlMNT PANEL.
bND
50V OR MDRE WLESS OTHERWISE SHIWN.
SW IN
pF
X VOLTS.
6
EE~
"AD
0
PCMLTAGE
MEASURED
WITH
32.5
MLTS
1
INPUT LEVEL
PJvD
ARE RMS VALUES)
m
THIS MAY RE APPROXIMATED BY A STEADY WISTLE
-80
DBV (0.1 mV RMSI ACROSS PINS
MI
L KHZ SOURCE. LINE OUTPUT
600
WSTER CONTROLS CLOCKWISE. PH3NES KNTROL
WL.
PHPlES OUTPUTS
OHMS.
GROLND EXCEPT
HEWM
METERS.
bND
MAY
PND
VARY
D OBTAINED WITH TONE OX: SWITCHED ON.
VAWES
GIVEN
VOLTAGES
I
DC
APPLIED
m
lwv
LOADED
MIT
WADED WITH
TAPE
SHMN.
WHERE
VALUES ARE TYPICAL
+
20%.
UL06
WILL VARY WITH
PS(E
TYPICAL
SM FOR SECTICNS C
CU
TO PREVENT THE
MR
AC
VOLTAGE
nett
WITH
X
AN
47K
bND
AC
I
#HE
TONE
OSC
TONE
09C.
BT
I
9V
6
E
F
C
D
G
Vcc
PK
GND
AUX
IOV
IND
8T2
OR
AC VOLTAGES SHOW FOR VL02B OBTAINED WITH LIMITER "IN"
7.
(THRESHOLD AT
PARAMETERS AND
AC VOLTAGES SHIWN FOR 930% OBTAINED WITH VU
8.
(~~5.3)
OF
SET
m
+Ik
ISM)
SETTING
IN~ICATE
bND
WILL VARY DEPENDING UWN CIRCUIT
OF
LIM
ADJ
CWTROL (W31.
o
w
AT
+4
rn~
LINE
ADJ
PUT.
CONTROL
T
eot
BOTTOll VIEW
WZG2
A
WlOl
A
-WmA
0-
C
(2-----o
D
I
e
3
4
5
5
-
E
-
F
-
G-
H-
J
-
K
cr-----O
L
-
M
-
N
-
P-
R
-
5-
Vcc/,
8
VE
C
PK
IND.
DRIVE
D
MIX
CHAN
E
UTE
TONEPWR
F
MIX
UiAN
GMIXCIlAN2
HCaEIMP3OVT
J
PREAMP
&!
K
PREAMP
I
OUT
L
SLATE
TMR
M
VU
OR
N PROG
P
A-0
BATT-
R
A-8
BArr+
SGND
3
I
WT
OUT
-
0
0----9
C
-
0
-
E
0------o
F
-
G
o-----O
W3Ol A VUDFZ
A single-pin coaxial
to be powered froman-11 io 18 volt source such as a video tape
The three
tors are individually switchable to balanced 600-ohm an external source will also provide simplex power to the also provlde s~mplex (phantom) power to the
line or low-impedance microphone level. In the MIC
position, either simplex (phantom) or A-B power
available at each input for powering condenser
microphones. Each input transformer is Mumetal
shielded for maximum resistance to electrical hum. When powering the mixer from an external source, the batteries
&socket professional audio input connec-
IS
The Slate-pushbutton inserts a 1-second low-frequency
tone (400 Hz) each time it is depressed, and it keeps the
slate microphone on as long as it is depressed.
recorder,
microphone inputs, but a battery is still required for A-B power.
--
--
Using .the.-On10ff-switch to turn the power on
starts the green Power On indicator LED
with a repetition rate of approxima~ly 1 second.
The LED continues to flash so long as the switch
is on.
-..-
.
..
-..-.-
automotive
-
flashing
.
. .
12
Vdc external power,jack.permits the mixer
electrical system or ac power converter. Such
may be left in place as backup in case of failure of the source.
Switchover to battery power is performed by removing the plug
from the 12 Vdc jack. To prevent the possibility of damage caused
by leaking batteries, remove the batteries during any prolonged
period of storage or nonuse.
-
--
.
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-
!
I
1
-,
The mixer requires 11 to 18 Vdc for operating power.
nal power is supplied by two standard rectangular 9-volt
alkaline-batteries(Duracell
P
inputs. Battery life
I
IMPORTANT: Use only alkaline batteries.
____I
IS
K~1604 ~r<~u~valent)w~ch-
approximately 8 hours.
A
thi~d-91volt-batte~:is used to supply
~3-~ower at each microphone input.
When the
Line
off for that input.
~nput selector switch is in the
position,
the power is automatically
t
Inter-
microphone
t
Individual Lo-Cut filter switches for each input reduce low- The VU-Meter is supplied set for 0
frequency interference from air-conditioner or fan noise, VU
wind, strong hum fields, or similar sources. The filters insert a 7 dB rolloff at 100 Hz with a slope of -6 dB per octave. Adjustment).
On Channel-1,-the. Gain-Control- knobpulls out to activate a 1 kHz tone
oscillator that serves as a level-setting
aid. The oscillator level is set with the
Master control and is indicated on the
VU Meter.
--
A built-in pushbutton-operated, electret condenser
slate microphone can be used either for identifying
-
-
recorded segments or as an emergency field,
microphone.
=
+
4
dBm. This level can be
changed by an internal adjustment (see section on VU Meter
,
-
,
,
I
The
Limiteflhreshold-and-VU-Meter_tfimpots
located through screwdriver slots below the battery compartment and to the left of the
A-BISimplex switches.
The VU Lama bushbutton momentarilv
---
luminates ;he Zier dlal:~; automatic timed
release shuts off the lamp after 5 seconds. The
lamp remains lit while the button is depressed.
The-re<Peal&ED flashes to indicate the onset
of limiting. When the Limiter is Out, the red LED
acts as an overload indicator and begins
flashing at 6 dB below output clipping level.
The Battery check pushbutton converts the VU
~ecr to a7battery
dicator while the button is depressed.
-
-
condition
orcircuit voltage in-
il-
are
Simplex or A-B power is selected by
-
--
-
means of switches directlybelow the battery
compartment, inside the battery door. In the
DYN position, no power is supplied to the
Mic inputs.
7
A13 5 mm mini jack provides an Aux-level Tape
iiL--
output with minimum clipping level of 0.5V RMS
(-6
dBV).
L
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-
-
--
s7
i
Each input- channel-has-its own-gaincontrol. The input
microphones is from -47 to
depending on the channel control setting. For line inputs, the clipping level
ranges from
depending on the control setting.
clipping- level for
-
17 dBV
+3 to +33 dBV, again
The Master gain control sets the output level at the
LinelMic and~a~e~ut~u~s. Gain is 40 dB from Mic In to
Mic Out or from Line In to Line Out; 90 dB from Mic In to
Line Out, 68 dB from Mic In to Tape Out, and 18 dB from
Line In to Tape Out.
The output Limiter has a threshold of
600-ohm Line output (4 dB below clipping), with comparable levels at the Mic and Tape outputs. The
threshold can be internally adjusted down to
(see section on Limiter Threshold Adjustment). The
Limiter attack time is
typical recovery time, for unobtrusive operation.
-
--
!
+
3
msec typical, with 500 msec
14 dBm at the
;
r
J
s
+3 dBm
s
A
b.5-mm-minijack and a quarjerjnchphonejackprovide two stereo headphone outputs that can
be used simultaneously. They are designed to
drive mono or stereo headsets with impedances
of 8 to 2,000 ohms. They can also be used to drive
up to four Aux-level tape recorder or amplifier inputs.
A beparate Phones volume control sets the level
at the
TCa~~eF~tpGt~;-maxii~m output is
1.6V RMS
(
+
4 dBV) to 200 ohms.
I
Two 3-pin professional audio output
-
--
connectors are individually switchable to
,
--
600-ohm Gne level or
microphone level. Minimum clipping levels
are
-
-
--
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--
I&-impedance
+
18 dBm (Line) and -34 dBV (Mic).
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-
-
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