Wheatstone Corporation A-32 User manual

A-32/A-20 On-Air Console
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OWNER'S MANUAL
August 1989
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BlWheot/tone Corporation
6720V I P Parkway Syracuse, N V 13211 (315455-7740)
23 p %I^IS2.~^ oOU •
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J I s
4-20/4-32
Radio On-Air
Consoles

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IMPORTANT!
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*OM-20 output module is supplied from factory with insert
points already bridged (via PCB mounted dipswitch)
In order to pass audio through your new console,
you must wire up insertion points in certain modules
Note in particular
MM-20 input modules
and the
OM-20 output* module
See "Connection" section in your manual for details

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ATTENTION!
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A-32 CONSOL : This manual applies to both A-20 (10 input) and A-32 (16 input) consoles
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May 1991
PS-20 POW R SUPPLY (load sheet drawing):
Voltage regulators (Q2 through Q5) are now using #4-40 steel screws, insulating shoulder
washers and metal #4-40 locking nuts
SL-20 ST R O LIN INPUT MODUL :
[4/91] The CR MUTE function has been dropped See D version schematic (SL-20D PCB)
ADDENDA TO A-20 CONSOLE OWNER'S MANUAL
Please note the following changes/additions to your manual documentation:

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TABL OF CONT NTS
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PARTS LISTS
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Specifications
System Signal Flow Diagram
G N RAL
Console Overview
Mainframe Installation
Cut-Out Dimension Drawing
System Ground
CONSOL I/O CONN CTIONS
General
Dipswitch Controlled Functions
Control Ports
Master I/O Pinout Drawing
Individual Module Pinouts
Console Bus Chart
OPTIONAL ACC SSORI S
Clock Control Card (CLK-5)
Timer Control Card (TM-6A)
Tape Remote Module (SS-6/FF-2)
Line Select Module (LS-6)
Multi-Phone Module (MP-32)
Intercom Module (ICM-32)
Studio Turret (ST-20)
Copystand
P RFORMANC GRAPHS
Level Diagrams
T CHNICAL NOT S
Testpoints
Updates
MODUL S CTION
Faceplate Drawings
Control Explanations
Signal Flow Diagrams
Interface Charts
Schematics
Load Sheets

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• gold contact interface
• fully regulated, short circuit protected
rackmount power supply (3*/ 2 " high)
• mating gold pin DB 25 connectors included
• 3 year limited warranty
• precision multi turn calibration trims throughout
• pre burned in, socket mounted ICs
• gold contact industry standard ON/OFF switches
• channel A/B logic follow
• hinged meterbridge solid oak cabinetry
• lexan laminated module panels
• fully enclosed aluminum chassis
• fully enclosed aluminum meterbridge
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THE A-20 ON-AIR BROADCAST CONSOLE
LOGIC CONTROLLED AUDIO — Since impeccable electrical specifications were the design objective, VCAs. FETs, and use of
line transformers were avoided to reduce the significant noise, distortion and bandwidth limitations that these component cn
employs a short turn on delay to avoid acoustic noise from the channel ON switch.
THE LOGIC SYSTEM — The A 20 provides an isolated contact closure from individual input module ON and Orr switcnes to
provide interface free machine starts The module can also accept external ON/OFF commands by simply receiving a contact
closure from cart machines, or a logic low command The module's A/B source selector switch also switches the logic commons for
the A and B machine control ports to allow a logic follow function.The A 20's internal logic is controlled by dipswitches located on
the input modules. Available functions include control room mute and on air tally relay, studio mute and studio on air tally relay,
and console timer restart. Additionally the control room module can be dipswitch programmed to provide a split cue mode that
places program in the left monitor speaker and cue in the right The control module also has a dipswitch selection to allow cue to
interrupt the headphone monitor t ..
INPUT CIRCUITRY — All line level inputs are electronically balanced and are capable of + 26dBm levels This type of active
circuitry optimizes bandwidth and distortion and avoids unnecessary use of line transformers. Additionally the line input modules
have front panel accessible multi turn screwdriver driven gain trim controls to accommodate a wide range of signal sources. Mic
modules also have a front panel gain trim control but also utilize a mic transformer, which is better suited to low level signals in high
RF environments i t
OUTPUT CIRCUITRY — The program., audition, mono, mix minus, control room and optional studio outputs are all electronically
balanced and capable of delivering + 28dBm levels. Multi turn front panel screwdriver adjustable gain trim controls are provided
HEADPHONE CIRCUITRY — A headphone output jack is provided, located below counter level Headphone derives its signal
from the control room source selector switch and may be programmed by an internal dipswitch to receive input module cue signals.
This switching action is automatically activated from the console's internal logic buses Headphone output level is set by a high
quality conductive plastic level control
CONTROL ROOM FUNCTION — The control room module receives its signal from a six position source selector switchbank
Source choices include program, audition, mono and two external electronically balanced stereo inputs. A long life conductive
plastic level control then drives the control room's electronically balanced outputs Control room signal is muted when control room
mic is ON The module can be internally dipswitch selected to operate in a split cue mode, where the cued module is placed in the
right monitor speaker and a dimmed mono sum signal is placed in the left. The studio mic module can be dipswitch selected to talk
back to the control room's cue circuit to facilitate intercom functions. A control room on air tally relay is activated whenever the
announcer microphone is energized
CONSOLE TIMER — The A 20 meterbndge comes standard with a digital elapsed time counter and corresponding control panel
(mounted in the lower portion of the OM 20 output module ) This control panel is provided with start/stop. hold, and reset buttons
Another handy feature is a recessed timer restart switch When activated it allows dipswitch pre programmed line modules to reset
the timer to zero and begin counting upon a channel ON command.
STUDIO FUNCTION — An optional studio module is provided with a six position source selector switchbank, a conductive plastic
level control and electronically balanced outputs, as well as a talkback button which allows the control room talent to communicate
to the studio output Also, an independent external talkback output is provided to feed an independent speaker when so desired
A studio on air tally relay is activated whenever the studio microphone is energized
LINE SELECTOR — An optional six source stereo line selector module is available that may be wired to the input port of line input,
control room or studio modules to expand their input capacir/
TAPE REMOTE MODULE — An optional tape remote module is available that provides twelve switches to enable full function
control of two remote tape machines The module is also available as six pairs of stop/start buttons to control six cart machines.
STUDIO TURRET — An optional family of studio turret and turret panels is available These panels include a crystal controlled
(or 60 Hz timebase) clock, elapsed time counter (which may slave from the console s restart bus), a headphone/speaker control
panel, a mic control panel (On. Off. Talkback, Cough), and an eight bank stereo selector panel.
MAINFRAME — The A 20 mainframe is unique, both in terms of structure and interface It utilizes an innovative approach to its
interface system that greatly improves connection reliability and ease of installation, uisng gold contact insulation dfsplacement (ID)
connectors and ribbon wire (developed by the computer industry for its superior reliability and maintenance characteristics) This
system replaces older motherboard technology and its inherent vulnerability to solder joint failure and loose debris shorting. Con 
sole I/O connections are made to 25 pin DB connectors mounted on the bottom plate of the console Mating gold contact connectors
plug into the underside of the console, allowing console placement close to walls and eliminating the need for flip uo procedures
(and allowing wiring changes during console operation) The gold contact connectors are far superior to the tin contact Molex type
and eliminate the need for bringing external wiring into the console s interior, a major source of RF contamination
PERFORMANCE — Performance is the most outstanding feature of the A 20 console A review of the specification page (following)
says it air This console in every way performs equal to its larger format counterparts. There is simply no compromise made in this
area.
IN SUMMARY, the A 20 On Air Broadcast Console is a significant achievement in console design in terms of ease of installation
service, integrity of connections and technical performance It borrows componentry and methods from both the computer and
audio industries. The A 20 is a perfect choice for stations planning an upgrade in signal quality or control room image It is also a
natural choice for newsroom and small production applications.
• 2 mic channels
• 8 stereo line channels
• 4 VU meters
• 1 elapsed time counter (w/auto restart)
• module machine start function
• Program and Audition stereo buses
• Cue bus
• Mix Minus bus
• automatic cue release
• A/B source select w/LED indicator
• control room module
• headphone function
• split/cue monitor or external cue out
• fully modular construction

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SMPTE IMD(Line in);
<0.008% (+ 20dBm out)
OUTPUT (Bus)
+ 30dBu max, + 20dBm
MIXING BUSES
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METERS
OFF ISOLATION
better than IQOdBfalKHz
SLEW RATE (Line)
12V/microsecond (bal out)
FADERS
100mm conductive plastic
PHASE SHIFT (Line in):
less than 12°(20Hz 20KHz)
CROSSTALK
80dB(&lKHz
STEREO SEPARATION (Lt Rt):
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55dB(fclKHz
Specifications and features subject to change without notice.
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THD + NOISE
Line input
Mic input
A — 20 CONSOLE MODULE LAYOUT
(INPUT MODULE TYPES DETERMINED BY CLIENT)
<0.003% (20Hz 20KHz (a. + 20dBm out)
<0.005% (1 KHz fa + 20dBm out)
±0.2dB (20Hz 20KHz)
±0.5dB, 30Hz 20KHz
28dB max
67dB max
GAIN TRIM RANGE
Stereo Line
Mic
20dB
36dB
50Kfi bal, + 26dBu max
1500 nom, OdB max
4 Lighted Mechanical VU
(2 PGM. 2 AUD. plus timer)
2 Stereo (Program. Audition)
1 Cue
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FREQUENCY RESPONSE
Line input
Mic input
NOISE (20Hz 20KHz).
Line input
Mic input (150(1 source)
INPUT GAIN
Stereo Line
Mic
better than 88dBm
EIN 128dB( 74dBm)
INPUT
Stereo Line
Mic
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PRELIMINARY SPECIFICATIONS: A 20 ON AIR BROADCAST CONSOLE
(All faders (a nominal settings ( 10dB); Gain OdB line. 54dB mic)
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A- 0 RADIO ON-AIR CONSOLE
SYSTEM FLOW DIAGRAM
! m mm
TRIM
LT PCM VU
"I p GMOUT LT
I(BALANCED)
PCM
ro cue
jp.sis.ff. ’ irsst.
MONO PCM MONITOR
LT/RT PCM MONITOR
m 1 mc « o OUT
J(BALANCED)
WA UMU5
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H ] PCM OUT RT
J (BALANCED)
PGM RT
0M — 0 OUTPUT MODULE
RT PGM VU
S*
AUD MONITOR LT
J*'"
" " *UC OUT LT
I(BALANCED)
L -
TO CUE CO -PC'
EXTERNAL TB CCNTRCL
AUD RT
AJO OUT »T
(BALANCED)
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ALQ MCNiTCR RT
-ACER i — 0-5;
RT AUO VU
GAIN ■R ’ M
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UCNO
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TURRET ANNOUNCER PANEL
' _Cy£ CCNTRC
AMP
LEVEL
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GUE OUTPUT ,
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; 5TUOIO SOURCE SELECT PANEL
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PWQCR au
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AuDinCN
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MONO
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TB TO STUDIO
EXTERNAL
re OUTPUT ,
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•10 START
SWITCH
STOP
SWITCH
STOP
SHTOi
LED
LEO
LED
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• S£°: 1
EXTERNAL
CONTROL
PORTS
1
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PATCH IN —
PATCH CUT -
1 *
TURRET
LISTEN PANEL
TURRET
CLOCK
O utput as SG n
SWITCHES
OUTPUT ASSIGN
SWITCHES
PATCH IN
PATCH OUT
patch in
PATCH CUT
PATCH IN
PATCH OUT
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CHANNEL
LCSC
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pa -C h IN
PATCH OUT
— •- N Q
CHAN CFF
OFT SW
— LAMP
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A R£M CCM - - -•
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— C-AN H
- CHAN on -
-CCUGH — -
CHAN
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Sw
SL — O STEREO
LI NE INPUT
MODULE
CR-20
CONTROL ROOM MODULE
OPTIONAL LS — 6
LINE SELECT MODULE
ST- O
STUDIO
TURRET
OPTIONAL
MM — 0
MIC INPUT
MODULE
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CAIN TRIM
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ZZZ2 P ' “ "
' EXT STEREOr[ R __ 2 tin *
’ LINE <KPUTSl , J -------
[ (U ALAN CEO) *- --
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1-HEM START
REM STCP - —
EXTERNAL A REM CCu -
CONTROL a REu COM
PORTS CHAN ON -■ -•
CHAN OFF —
1 ------- READY
OPTIONAL SS-fi TAPE REMOTE MODULE
(1 OF a S1MTCH SETS SHOWN)
-1 C ain TR;
-2^;
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LH
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1 STEREO ■
; line , “
; inputs : r;
Mix-M NUS CUT
(9 al » s C£D)
J OPTIONAL FF- TAPE REMOTE MODULE J
1 (1 OF SWTOH SETS SHOWN) [
Ssk
110 ZI ’
;! off I icough !
ACN CONTROL MONITOR ’
as i r~l sil
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TURRET TIMER
CH ANNE I .--1? — .
■ 0=:c F-ff 7 !

GENERAL
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A-20 CONSOLE OVERVIEW:
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STANDARD NODULES are as follows:
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For a better understanding or the console, refer to the A-20 module
Illustrations and signal flow diagrams In conjunction with the following
section:
The WHEATSTONE A-20 ON-AIR BROADCAST CONSOLE Is a modular,
2-channel console for radio on-air applications The console comes
supplied with individual stereo PROGRAM and AUDITION outputs, plus a
MONO SUM (derived from PROGRAM) and a MIX-MINUS output The mainframe
comes supplied with the following standard modules: 10 inputs (2 mono
mic [MM-20], 8 stereo line [5L-20D, a control room module (CR-20), an
output module (0M-20), and 3 blank positions (for optional modules; see
below) The console meterbridge houses 4 VU meters (PGM LT, PGM RT,
AUD LT and AUD RT) and a digital timer A rackmount power supply
(failsafe option available) is included
(1) MM-20 MONO MIC INPUT: A dual source mono microphone input
module with A/B select switch (w/LED indicator), front panel
multi-turn gain trimpot, output assign (PGM and/or AUD), long-throw
conductive plastic fader, and lighted channel ON and OFF switches
Logic functions (selectable via internal dipswitch) are as follows:
mix-minus assign, talkback to studio, control room mute, and studio
mute The module also has the following external control ports: tally
on, tally off, channel on, channel off, and cough Note that remote
control functions will follow the source select switch A/B setting
(2) 5L-20 STEREO LINE INPUT: A dual source stereo line input module
with A/B source switch (w/LED indicator), left and right multi-turn
front panel gain trimpots, output assign (PGM and/or AUD), CUE
(w/LED indicator), long-throw conductive plastic stereo fader, and
lighted channel ON and OFF switches Logic functions (selectable via
internal dipswitch) are as follows: mix-minus assign, control room
mute, timer restart, and local/external ready light indicator The
module also has the following external control ports: remote start,
remote stop, channel on, channel off, and ready Note that remote
control functions will follow the source select switch A/B setting
(3) CR-20 CONTROL ROOM MODULE: This module controls monitor
source selection (PGM, AUD, and MONO console signals, plus two
external stereo line inputs), control room level (w/on switch),
headphone level (the module has a built-in headphone amp) and CUE
level CUE can be internally set (via dipswitch) to automatically
interrupt CR and/or HDPN The module also has a built-in on-air tally
relay
(4) 0M-20 OUTPUT MODULE: Contains front panel multi-turn trimpots
for PGM, AUD, MONO and MIX-MINU5 outputs, plus VU trims for the PGM
and AUD meters This module also houses the timer control panel
(Start/Stop, Reset, Hold, Auto-Restart)