Pacific Research BMX-III-18 User manual

BMX-III
Operations
&
Technical
Manual
PR&E Document #75-10
Broadcast Console
2070 Las Palmas Drive • Carlsbad, CA 92009 USA • Tel: [phone] FAX: [phone] • E-Mail: [email protected] • Internet: http://www.pre.com
P A C I F I C R E S E A R C H & E N G I N E E R I N G C O R P O R A T I O N
BMX-18 Mainframe: PR&E # 99-260-3CU
BMX-22 Mainframe: PR&E # 99-260-4CU
BMX-26 Mainframe: PR&E # 99-260-5CU
BMX-30 Mainframe: PR&E # 99-260-610U
BMX-34 Mainframe: PR&E # 99-260-7CU

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PR&E DOCUMENT #75-10
STATUS PAGE
(Revision C - June 1999)
Thislistingprovidesareferenceofcurrentpagesofthisdocument,andtheirrevisionnumbers(i.e.,A.1,A.2,etc.).
WhenarevisiontothisdocumentisreceivedfromPR&E,simplyreplacetheoldpageswiththenewones,discard
the old pages, and post the new status page in the front of this manual (NOTE: It may be desirable to retain
replaced status pages in order to have a record of document changes). If deemed necessary by PR&E’s
Engineering Department, comment information relating to any change may also be included on this page.
Page No. Revision Comments
ALL B Corporate Name Change
4,5,78,89 C Standard output level is now
90,100,101 +4 dBu instead of +8 dBu.
References in text updated.
ALL C Files changed to PC format.
Text & graphics updated.
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TABLE OF CONTENTS
1.0 GENERAL INFORMATION 1
1.1 Introduction 1
1.2 Description 1
1.3 Specifications 3
1.4 Warranty Information 6
2.0 INSTALLATION 7
2.1 General Guidelines 7
2.2 Cable Preparation 8
2.3 Mainframe Configuration 10
2.3.1 Control Panel 10
2.3.2 Meter Panel 11
2.3.3 Connector Panel 12
2.4 Grounding And Shielding 14
2.5 Power Connection 14
2.6 Patch Point Connection 15
2.7 Audio And Logic Connection 16
2.7.1 Microphone Input Module Connection 18
2.7.2 Stereo Line Input Module Connection 19
2.7.3 Stereo Line Output Amplifier Connection 20
2.7.4 Monitor Module Input Connection 21
2.7.5 Control Room Monitor Module Connection 22
2.7.6 Two-Studio Monitor Module Connection 23
2.7.7 Monaural Line Output Amplifier Connection 24
2.7.8 Telco Mix Module Connection 25
2.7.9 Send And Return Module Connection 26
2.7.10 Slate/Talkback/Test Osc. Module Connection 27
2.7.11 Meter Switcher Module Connection 28
2.7.12 Remote Line Selector Module Connection 29
2.7.13 Timer Control Connection 30
2.8 Module Remote Control Capabilities 31
2.8.1 Microphone Input Module Remote Control 31
2.8.2 Stereo Line Input Module Remote Control 32
2.8.3 Control Room Monitor Module Remote Control 33
2.8.4 Two-Studio Monitor Module Remote Control 35
2.8.5 Send And Return Module Remote Control 37
2.8.6 Slate/Talkback/Test Oscillator Remote Control 38
2.9 Module Internal Option Switches 40
2.9.1 Microphone Input Module Option Switches 40
2.9.2 Stereo Line Input Module Option Switches 42
2.9.3 Control Room Monitor Module Option Switch 44
2.9.4 Two-Studio Monitor Module Option Switch 46
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2.9.5 Telco Mix Option Switch 47
2.9.6 Send And Return Module Option Switches 48
2.9.7 Slate/Talkback/Test Osc. Module Option Switch 49
2.9.8 Meter Switcher Module Option Switch 50
3.0 OPERATION 51
3.1 Microphone Input Module 51
3.2 Microphone Input Module With Sends 52
3.3 Stereo Line Input Module 53
3.4 Stereo Line Input Module With Sends 54
3.5 Stereo Line Output Amplifier 55
3.6 Control Room Monitor Module 56
3.7 Two-Studio Monitor Module 57
3.8 Monaural Line Output Amplifier 58
3.9 Monaural Output/Telco Mix Module 59
3.10 Send And Return Module 60
3.11 Monaural Output/Telco Mix/Send And Return Module 61
3.12 Slate/Talkback/Test Oscillator Module 62
3.13 Meter Switcher Module 63
3.14 Remote Line Selector Module 64
3.15 Timer Control Panel 65
4.0 EQUIPMENT DESCRIPTION 66
4.1 Mainframe 66
4.1.1 Function 66
4.1.2 Circuitry 66
4.2 Microphone Input Modules 67
4.2.1 Function 67
4.2.2 Circuitry 67
4.3 Stereo Line Input Modules 70
4.3.1 Function 70
4.3.2 Circuitry 70
4.4 Stereo Line Output Amplifier 72
4.4.1 Function 72
4.4.2 Circuitry 72
4.5 Control Room Monitor Module 73
4.5.1 Function 73
4.5.2 Circuitry 73
4.6 Two-Studio Monitor Module 75
4.6.1 Function 75
4.6.2 Circuitry 75
4.7 Monaural Line Output Amplifier 76
4.7.1 Function 76
4.7.2 Circuitry 77
4.8 Monaural Output/Telco Mix Module 77
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4.8.1 Function 77
4.8.2 Circuitry 77
4.9Send And Return Module 78
4.9.1 Function 78
4.9.2 Circuitry 78
4.10Monaural Output/Telco Mix/Send And Return Module 80
4.11Slate/Talkback/Test Oscillator Module 80
4.11.1Function 80
4.11.2Circuitry 80
4.12Meter Switcher Module 85
4.12.1Function 85
4.12.2Circuitry 85
4.13Remote Line Selector Module 86
4.13.1Function 86
4.13.2Circuitry 86
4.14VU Meter Power Regulator 86
4.14.1Function 86
4.14.2Circuitry 87
4.15VU Meter Buffer Amplifier 87
4.15.1Function 87
4.15.2Circuitry 87
4.16Power Supply Assembly 87
4.16.1Function 87
4.16.2Circuitry 87
5.0 OPTIONS AND MODIFICATIONS 89
5.1Phantom Microphone Powering 89
5.2Output Level Conversion (+4 dBu to +8 dBu) 89
5.3Stereo Send Operation 90
5.4Input Module Steady Cue Indication 91
5.5Using Send Circuits For Telco Operations 91
5.6Talkback/Intercom Module 94
6.0MAINTENANCE AND ALIGNMENT 98
6.1Routine Maintenance 98
6.1.1 Checking Power Supply Voltages 98
6.1.2 Lamp Replacement 98
6.1.3 Button Replacement 99
6.1.4 ColletKnob Removal 99
6.2Troubleshooting (Module Removal) 99
6.3Level Alignment 100
6.4 Tool Kit 102
6.5Spare Parts Kit 102
6.6Replacement Parts 104
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7.0 DRAWINGS AND SCHEMATICS 110
7.1 Functional Block Diagrams (Console Block Diagram) 112
7.1.1 Microphone Input Module Block Diagram 113
7.1.2 Stereo Line Input Module Block Diagram 114
7.1.3 Stereo Line Output Amplifier Block Diagram 115
7.1.4 Control Room Monitor Module Block Diagram 116
7.1.5 Two-Studio Monitor Module Block Diagram 117
7.1.6 Monaural Line Output Amplifier Block Diagram 118
7.1.7 Telco Mix Module Block Diagram 119
7.1.8 Send And Return Module Block Diagram 120
7.1.9 Slate/Talkback/Test Oscillator Block Diagram 121
7.1.10 Meter Switcher Module Block Diagram 122
7.1.11 Remote Line Selector Module Block Diagram 123
7.2 Microphone Input Module Schematic 124
7.3 Microphone Input Module With Sends Schematic 129
7.4 Stereo Line Input Module Schematic 134
7.5 Stereo Line Input Module With Sends Schematic 139
7.6 Stereo Line Output Amplifier Schematic 144
7.7 Control Room Monitor Module Schematic 146
7.8 Two-Studio Monitor Module Schematic 149
7.9 Monitor Module Switching Schematic 153
7.10 Monaural Line Output Amplifier Schematic 154
7.11 Monaural Output/Telco Mix Module Schematic 155
7.12 Send And Return Module Schematic 157
7.13 Mono/Telco/Send And Return Module Schematic 160
7.14 Slate/Talkback/Test Oscillator Module Schematic 165
7.15 Talkback/Intercom Module 168
7.16 Meter Switcher Module Schematic 170
7.17 Remote Line Selector Module Schematic 171
7.18 VU Meter Buffer Amplifier Schematic 172
7.19 Meter Power Regulator Schematic 173
7.20 Power Supply Assembly Schematic 174
7.21 Output Amplifier Function Module Schematic 175
7.22 Instrumentation Amplifier Function Module Schematic 176
7.23 990 Function Module Schematic 177
7.24 Console Main Mother Board Schematic 178
7.25 Monitor Selector Mother Board Schematic 179
7.26 Remote Line Selector Mother Board Schematic 180
7.27 Console Wiring (Edge Connector Layout) 181
7.27.1 Microphone Input Module Audio 182
7.27.2 Stereo Line Input Module Audio 183
7.27.3 Input Module Logic 184
7.27.4 Program Amplifier Output 185
7.27.5 Audition Amplifier Output 186
7.27.6 Utility Amplifier Output 187
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7.27.7 Monitor Module Input 188
7.27.8 Control Room Monitor Module 189
7.27.9 Two-Studio Monitor Module 190
7.27.10 Monaural Amplifier Output 191
7.27.11 Telco Mix 192
7.27.12 Send And Return 193
7.27.13 Slate/Talkback/Test Oscillator Audio 194
7.27.14 Slate/Talkback/Test Oscillator Logic 195
7.27.15 Meter Switcher Module 196
7.27.16 Remote Line Selector Inputs 197
7.27.17 Remote Line Selector Outputs 198
7.27.18 Meter Power 199
7.27.19 Timer Control 200
7.27.20 Remote Control Panel Cable Assembly 201
8.0 ACCESSORIES 202
8.1 Tape Machine Remote Control Panels 202
8.1.1 Cart Recorder Remote Control Panel 202
8.1.2 Tape Recorder Remote Control Panel 202
8.2 Clocks And Timers 203
8.2.1 TD-2 Digital Clock 203
8.2.2 TD-171 Digital Slave Clock 204
8.2.3 DT-4 Digital Timer 205
8.3 PPM Meter 206
8.4 Redundant Power Supply Coupler Unit 206
8.5 Logic Interfaces 207
8.5.1 TCI-2A Cartridge Interface 209
8.5.2 CI-2 Cartridge Interface (+12 to +28 Volt Logic) 210
8.5.3 CI-2 Cartridge Interface (+5 Volt Logic) 210
8.5.4 TI-2 Tape Interface 210
8.5.5 TT-3 Turntable Interface 211
8.5.6 WL-2 Warning Light Interface 212
8.5.7 Dual Relay Interface 212
8.5.8 Cassette Skimmer Interface 212
8.6 Accessory Schematics 214
8.6.1 Cart Recorder Remote Control Panel 215
8.6.2 Tape Recorder Remote Control Panel 216
8.6.3 TD-2 Digital Clock 217
8.6.4 TD-171 Digital Slave Clock 218
8.6.5 DT-4 Digital Timer 219
8.6.6 Timer Control Panel 220
8.6.7 PPM Buffer Amplifier 221
8.6.8 Power Supply Coupler Unit 222
8.6.9 TCI-2A Cartridge Interface 223
8.6.10 CI-2 Cartridge Interface 224
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8.6.11 TI-2 Tape Interface 225
8.6.12 TT-3 Turntable Interface 226
8.6.13 WL-2 Warning Light Interface 227
8.6.14 Dual Relay Interface 228
8.6.15 Cassette Skimmer Interface 229
8.6.16 #99-38 Console To Interface Cable 230
8.6.17 #99-464 Console To TI-2 Interface Cable 231
8.6.18 #99-465 Console To CI-2 Interface Cable 232
8.6.19 #99-453 Control Cable, 9-Pin Male To Male 233
8.6.20 #99-454 Control Cable, 12-Pin Male To Male 234
8.6.21 #99-455 Control Cable, 24-Pin Male To Male 235
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1.0 GENERAL INFORMATION
This chapter contains an introduction to the BMX Series III Broadcast Console Technical Manual, an
overview of the BMX III’s features, its specifications and warranty information.
1.1 INTRODUCTION
Congratulations on your decision to join the growing ranks of Pacific Research & Engineering
Corporation (PR&E) broadcasters. PR&E is in the business of supplying the finest audio systems to
the world’s leading broadcast facilities. Your decision to go with PR&E means that you expect more
than simple working hardware. Please be assured that it is our strong desire to provide each of our
customers with the kind of products, systems, documentation and support that we would specify if we
were in your position.
We invite your comments and suggestions for improvement of this document, and of all our services.
By constant attention to our customer’s needs, we will continue to earn our reputation for excellence,
and to refine our understanding of the requirements of the marketplace.
Thismanualisdesigned to provide the information required tounderstand,install,operateandmaintain
theBMXIIIBroadcastConsole. Itisassumedthatthereaderhasaworkingknowledgeofaudiocontrol
consoles, systems and installation practices. The BMX III is a very sophisticated device with an
extensive range of features and capabilities. To obtain the maximum benefit of the console’s
capabilities, it is strongly recommended that the Installation, Operation, and Equipment Description
chapters of this manual be read thoroughly prior to installing the console.
Each BMX III is specifically configured to the customer’s requirements, thoroughly tested, and
“burned-in” prior to packing for shipment. Should you encounter any difficulty during installation or
initial operation, we recommend that you contact PR&E for assistance.
1.2 DESCRIPTION
The BMX III is designed with the capacity to accomplish almost any type of stereo on-air audio control
taskinaradiobroadcastfacility.Inaddition,patchpointsaresuppliedforalltheinputandthelineoutput
amplifiers for the insertion of processing equipment. This gives the BMX III the capability for creative
production as well as on-air applications.
The BMX III was developed in parallel with our AMX Broadcast Operations Console, and many of the
function modules were derived from the AMX concepts. For example, the BMX III Microphone and
BMX SERIES III BROADCAST CONSOLE
TECHNICAL MANUAL

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StereoLineInputModulesarealmostidenticaltotheAMXmodules,withtheexceptionofthetwoSend
circuits, while the Control Room Monitor, Two-Studio Monitor, Stereo Line Output, and Slate/
Talkback/Test Oscillator Modules are identical. The BMX III will also accommodate the AMX input
modules with Sends, along with the optional Send And Return Module. The Monaural Output, Telco
MixandSendAndReturnModulesfortheAMX havebeencombinedintoa singlemodulefortheBMX
III, but all are still available as individual modules, depending upon customer requirements.
NOTE: The BMX III was not derived from the BMX Series II, but was designed to be part of the ABX
and AMX family of broadcast consoles. Therefore, the BMX Series II and Series III consoles do not
share any common modules or subassemblies.
The BMX III is currently being produced in seven mainframe sizes which will accommodate 10, 14,
18, 22, 26, 30 and 34 input modules. The term “input modules” refers to microphone and line input
modules. The seven mainframes are virtually identical with the only difference being the available
space for the meter panel.
In order to realize the full potential of the BMX III, it is important that the user become fully acquainted
withtheextensiveaudio and logic control functions available. Theconsoleandmoduleblockdiagrams,
located in Chapter 7 of this document, show the audio signal flow and the extensive logic control inputs
and outputs which are available to the user. These block diagrams present a concise picture of the
modules’ operating functions and features as well as the overall console system, and can be very useful
in determining how to best utilize your BMX III.
The BMX III has been designed functionally, mechanically and electronically to provide the maximum
value in performance and features of any currently available broadcast console. Highest quality
components and circuit designs are used throughout the console. The gain structure of the console has
been designed so that normal operation is easily achieved without danger of internal clipping (when
operating the amplifiers at optimum signal to noise conditions).
The input modules accommodate the range of input levels normally found in broadcast operations
without the use of external pads or amplifiers. A patch point is provided for each input position after
theinputamplifierandbefore the fader. This is the optimumpointatwhichto insert external processing
devicessuchaslimitersandequalizers.Patchpointsarealsoprovidedineachmainoutputchannel(after
the mixing amplifier and before the line output amplifiers).
All console inputs and program outputs are balanced, for best noise rejection and simplified system
grounding. When properly installed using the information in this manual, the BMX III console is free
of internal pops, clicks, and radio-frequency interference (RFI).
The separately packaged power supply is fully regulated, and is protected with magnetic circuit
breakers, as well as electronic safeguards against excessive current and line voltage fluctuations. The
powersupplyprovidesfourseparatevoltageoutputs.Twooftheseoutputs(±22volts)areusedtopower
the audio circuitry. The third output (+12 volts) is used to power the logic control circuitry, lamps and
relays.Thefourth output (+ 48 volts)is for the phantom poweringof condenser microphones connected
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1.3 SPECIFICATIONS
Following is a list of specifications for the BMX III Broadcast Operations Console:
MICROPHONE INPUTS
Source Impedance 150 ohms.
Input Impedance 1000 ohms minimum, balanced.
Input Level Range Adjustable from -60 dBu to -35 dBu.
Input Headroom Greater than 30 dB above nominal input.
HIGH LEVEL INPUTS
Source Impedance 600 ohms.
Input Impedance Greater than 40K ohms, balanced.
Input Level Range:
Line Input Module Adjustable from -12 dBu to +4 dBu.
Return Module Adjustable from -15 dBu to +4 dBu.
Monitor Module Inputs Nominal +4 dBu/+4 dBu.
Input Headroom Greater than 30 dB above nominal input.
MAIN OUTPUTS
Load Impedance 600 ohms and greater.
Source Impedance 30 ohms, balanced.
Output Level Range Adjustable from +4 dBu to +4 dBu.
Maximum Output Levels:
Line Output Amplifiers +28 dBm, 600 ohm load.
Send Module +26 dBm, 600 ohm load.
MONITOR OUTPUTS
Main Outputs:
Load Impedance 600 ohms or greater.
Source Impedance 30 ohms, unbalanced.
Output Level 0 dBu nominal, +20 dBu maximum.
Headphone Outputs:
Load Impedance 45 ohms or greater.
Source Impedance Less than 4 ohms.
Output Level 0 dBu nominal, +20 dBu maximum.

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PATCH SENDS AND RETURNS
Patch Send Outputs Nominal -10 dBu; unbalanced.
Patch Return Inputs Nominal -10 dBu; 40k ohm balanced and bridging.
FREQUENCY RESPONSE
Microphone Input to Program Output +0 dB, -0.9 dB, 20 Hz to 20 kHz.
Line Input to Program Output +0 dB, -0.8 dB, 20 Hz to 20 kHz.
NOISE
Microphone Input Amplifier -127dBuequivalent input noise, 150ohmsource, 20 kHz
bandwidth.
Line Input Amplifier -88 dBu equivalent input noise, 600 ohm source, 20 kHz
bandwidth.
Output Noise with one microphone 76 dB below output, reference +4 dBu, 150 ohm
channel ON, fader at -15 dB, source, 20 kHz bandwidth.
Input sensitivity at -50 dBu
Output Noise with one line 80 dB below output, reference +4 dBu, 600 ohm
channel ON, fader at -15 dB, source, 20 kHz bandwidth.
Input sensitivity at +4 dBu
Output Noise with no input 82 dB below output, reference +4 dBu, 20 kHz
channels ON bandwidth.
DISTORTION, T.H.D.
Mic Input to Program Output Less than 0.02%, 20 Hz to 20 kHz, -50 dBu input, +4 dBu
output into 600 ohm load, 80 kHz meter bandwidth; less
than 0.01 at 1 kHz, +28 dBu output.
Line Input to Program Output Lessthan0.008%, 20Hzto 20kHz,+4dBuinput,+4dBu
output into 600 ohm load, 80 kHz meter bandwidth; less
than 0.01 at 1 kHz, +28 dBu output.

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DISTORTION, I.M.D.
Mic Input to Program Output Lessthan 0.008 %, -50 dBuinput, +4 dBu output into600
ohm load; less than 0.01% at +28 dBu output.
Line Input to Program Output Less than 0.005 %, +4 dBu input, +4 dBu output into 600
ohm load; less than 0.01% at +28 dBu output.
CROSSTALK
Interchannel Crosstalk Less than -85 dB at 1 kHz; less than -75 dB at 20 kHz.
POWER REQUIREMENTS
120 VAC, ±8%, 50/60 Hz
BMX III-10, fully configured 360 watts.
BMX III-14, fully configured 390 watts.
BMX III-18, fully configured 420 watts.
BMX III-22, fully configured 450 watts.
BMX III-26, fully configured 480 watts.
BMX III-30, fully configured 500 watts.
BMX III-34, fully configured 520 watts.
NOTES:
A) These specifications are for the basic signal paths, per channel, with either or both channels
of a stereo pair operating, and with 600 ohm loads connected to the program outputs.
B) 0 dBu corresponds to an amplitude of 0.775 volts RMS regardless of the impedance of the
circuit. It is the same voltage value as 0 dBm measured in a 600 ohm circuit. This enables
convenient level measurement with meters calibrated for 600 ohm circuits.
C) Noise specifications are for a 14-input console; larger consoles will have slightly reduced
signal to noise ratios due to increased summing amplifier gain. Noise specifications are
based upon a 20 kHz measurement bandwidth; the use of a meters with 30 kHz bandwidth
will result in a noise measurement increase of approximately 1.7 dB.
Pacific Research & Engineering Corporation reserves the right to change specifications without notice or obligation.

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1.4 WARRANTY INFORMATION
This product carries a manufacturer’s warranty which is subject to the following guidelines and
limitations:
A) Except as expressly excluded hereinafter, Pacific Research & Engineering Corporation
(“Seller”)warrantsequipmentofitsownmanufactureagainstfaultyworkmanshiportheuse
of defective materials for a period of one (1) year from date of shipment to Buyer. The
liability of the Seller under this Warranty is limited to replacing, repairing or issuing credit
(at the Seller’s discretion) for any equipment, provided that Seller is promptly notified in
writing within five (5) days upon discovery of such defects by Buyer, and Seller’s
examination of such equipment shall disclose to its satisfaction that such defects existed at
the time shipment was originally made by seller, and Buyer returns the defective equipment
to Seller’s place of business in Carlsbad, California, packaging and transportage prepaid,
with return packaging and transportage guaranteed.
B) Equipment furnished by Seller but manufactured by another shall be warranted only to the
extent provided by the other manufacturer.
C) Thermalfilamentdevicessuchaslampsandfusesareexpresslyexcludedfromthiswarranty.
D) The warranty period on equipment or parts repaired or replaced under warranty shall expire
upon the expiration date of the original warranty.
E) This Warranty is void for equipment which has been subject to abuse, improper installation,
improper operation, improper or omitted maintenance, alteration, accident, negligence (in
use,storage, transportationorhandling),operation notinaccordancewithSeller’soperation
and service instructions, or operation outside of the environmental conditions specified by
Seller.
F) This Warranty is the only warranty made by Seller, and is in lieu of all other warranties,
includingmerchantabilityandfitnessforaparticularpurpose,whetherexpressedorimplied,
except as to title and to the expressed specifications contained in this manual. Seller’s sole
liability for any equipment failure or any breach of this Warranty is as set forth in
subparagraph A) above; and Seller shall not be liable or responsible for any business loss or
interruption, or other consequential damages of any nature whatsoever, resulting from any
equipment failure or breach of this warranty.

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2.0 INSTALLATION
This chapter provides instruction in the proper installation of the BMX III Broadcast Operations
Console. Includedare sectionsdescribinggeneral installationguidelines,cable preparation,mainframe
configuration, grounding and shielding, power connection, patch point connection, audio and logic
connection, remote control connection, and module internal option switches.
2.1 GENERAL GUIDELINES
The BMX III should be carefully unpacked and inspected for any shipping damage. If the inspection
reveals any damage, immediately file a claim with the delivering carrier. The packing material should
be kept as evidence of mishandling, as well as to allow return of the equipment to the factory, if
necessary.
Includedwiththeconsolearethetoolandsparepartskits(asdescribedinChapter6),andtheappropriate
connector kit, which contains all of the Molex connector housings and pins necessary to prepare the
audio input/output and logic cables (as described in Section 2.2).
The console is physically installed by setting it into a cutout in the work surface of the studio cabinetry
(console and cutout dimensions are provided in Figure 2.1). Prior to installing the mainframe, a final
checkshouldbe made to confirm that thecutout dimensions are correct. Also, be surethatthe cabinetry
is in its proper position and leveled, as it is unlikely that the cabinetry can be moved, squared or leveled
once the weight of the BMX III has been added.
NOTE: ThecabinetryinwhichtheBMXIIIistobemountedmustbeofsufficientlysturdyconstruction
to support the console.
FIGURE 2.1 CONSOLE DIMENSIONS
A
B
TOP VIEW
5-3/4"
6-13/16"12-9/16"
26-9/16"
5"
CUTOUT
24-7/8"
C
SIDE VIEW
24-7/16"
10-1/4"
DIMENSION TABLE
CONSOLE A B C
BMX III-14
BMX III-18
BMX III-22
BMX III-26
38"
44"
50"
56"
36-1/2"
42-1/2"
48-1/2"
54-1/2"
36-3/4"
42-3/4"
48-3/4"
54-3/4"
BMX III-30
BMX III-34
62
68
60-1/2"
66-1/2"
60-3/4"
66-3/4"
BMX III-10 32" 30-1/2" 30-3/4"

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Theconsolemainframeissupportedbythehardwoodoakendpanels,andisactuallysuspendedbetween
the two end panels, with the front oak piece serving only as trim molding.
NOTE: Care should be taken to avoid locating the console within six feet of any intense electromag-
netic hum fields such as are produced by large power transformers and motors. Likewise, cables to and
fromtheconsoleshouldberoutedtoachievemaximumpracticaldistancefromACmainspowerwiring.
Particularattentionshouldbepaidtosomeofthelow-cost,supposedly“professional”,poweramplifiers
whichhaveappearedinthemarketplace. Inmanycasesthelowcosthasbeenpartiallyachievedthrough
the use of small core power transformers operating on the edge of saturation. While these units may
operate to their own specifications, the electromagnetic fields they radiate may impair the performance
of the console, neighboring turntables, tape recorders and cartridge machines.
Signal, logic and power connections are made to the connector panel located at the rear of the console.
This panel is recessed to provide the installer flexibility of wire routing in console installation.
The power supply is usually installed in the console support cabinetry using EIA standard rack rails.
Adequateventilation must beprovided for theproper dissipation ofheat. The power supplyis designed
for convection cooling by the two massive rectifier/regulator heat sinks located on opposite sides of the
chassis. Large heat sinks were chosen over the use of fans to eliminate the problems of dust circulation,
noise, and potential mechanical failure associated with fan cooling.
Install legend strips by sliding them into the tops of the legend panels. Monitor legend strips are 0.6
inch wide by 5.15 inches high (15 mm by 131 mm); Remote Line Selector legend strips are 0.6 inch
wide by 5.7 inches high (15 mm by 145 mm); Meter Switcher legend strips are 0.6 inch wide by 2.8
inches high (15 mm by 71 mm). Vertical switch spacing is 0.6 inch (15 mm).
2.2 CABLE PREPARATION
Before beginning the installation, a plan should be drawn up showing how the system will be
interconnected(use the module pin-out informationcontained in Section 2.7 asa guide). All cables and
connectors should be tagged with numbers and/or legends, and logged.
Only unspliced (preferably new) cables should be used in connecting the mainframe. Audio
connections should be made with 2-conductor stranded insulated foil shielded cable with drain wire.
The cable used should be equivalent to Belden types 8451, 9451, or 8761.
Strip the cable insulation jacket and foil shield back about 1-1/2 inches, and sleeve the shield drain wire
with heat-shrink tubing, leaving about 3/16 inch of the wire exposed. Then, strip the insulation of each
signal wire back about 3/16 inch, and sleeve the shield (at cable ends) with heat-shrink tubing.
NOTE: Itisveryimportanttosleevetheshielddrainwireandtheshield(atcableends)withheat-shrink
tubing. This is the only means of assuring an installation according to recommended grounding
procedures.

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BMX SERIES III CONSOLE
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PACIFIC RESEARCH & ENGINEERING
The Molex pins are designed so that the short tab “ears” are crimped onto the stripped wire to make the
electrical connection, while the long “ears” are crimped over the insulated section of the wire to help
support the connection.
Inorder tocrimp,insertthe shortearsofthe Molexcrimppinintonotch“B”of thecrimpingtool(PR&E
#70-3), with the ears pointing toward the letter “B”. Insert the wire into the terminal so that the stripped
portion is between the short crimp ears, and the insulation is between the long crimp ears. Crimp the
short ears.
Now place the long ears of the pin into tool notch “A”, with the ears pointing toward the letter “A”.
Crimp the long ears over the insulated section of wire. See Figure 2.2 for an example of a properly
crimped Molex pin.
NOTE: When using the ratchet type Molex Crimping Tool #HTR-1719-C (PR&E #70-5), place a pin
into slot “B” with the long ears on the “B” of the tool and pointing toward the letter “B”. Place the wire
into the tool from the “B”, and then crimp the pin.
Logic control cables should be fabricated in a similar manner using 22 gauge multiple conductor, non-
shielded, jacketed cable. The number of conductors required will be determined by application.
Once the pins are crimped, they may be inserted and locked into the nylon connector housing in
accordance with the pin-out diagrams contained in Section 2.7. A click can be felt indicating that the
locking ears on the pin have set. If a pin is inserted in the wrong connector position, or it is desired to
make a circuit change, use the connector pin extractor tool (PR&E #70-4) to release the pin and press
it out of the connector housing.
FIGURE 2.2 MOLEX CRIMP PIN
WIRE VISIBLE IN WINDOW
INSULATION CRIMP
(STRAIN RELIEF)
FLARE
WIRE
PIN LOCATING TAB
(DO NOT CRIMP OR BEND) CONDUCTOR (WIRE) CRIMP
TERMINAL "WINDOW"

REVISION C
BMX SERIES III CONSOLE
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PACIFIC RESEARCH & ENGINEERING
2.3 MAINFRAME CONFIGURATION
EachBMXIIImainframeisfactoryconfiguredtothecustomer’sorderbytheinstallationofmicrophone
input, line input and other modules in their specified and/or dedicated locations. This section contains
descriptions of the BMX III mainframe’s control panel, meter panel and connector panel.
2.3.1 Control Panel
Figure 2.3 illustrates the control panel layout of an BMX III-14 console. The positions identified by
module names are dedicated to those modules only, and will not accept any other type of plug-in
module.
The positions indicated by shading are “optional”, and blank panels will be installed in these positions
whenno modules arepresent. Any unused “optional”module positions maybe used forthe installation
of customer designed special purpose panels. OPTION cutouts have been provided in the Molex
connectorpanelfortheroutingofwiringfromthesepositionstotherearoftheconsole(referenceFigure
2.5).
NOTE: The “optional” module positions labeled A through E are pre-wired with 24-pin logic cables.
These cables are routed to corresponding rear panel OPTION cutouts, as defined in Figure 2.5.
FIGURE 2.3 CONTROL PANEL LAYOUT
INPUT MODULES 1 - 14
PROGRAM AMPLIFIER
AUDITION AMPLIFIER
UTILITY AMPLIFIER
MONO OUTPUT/TELCO MIX/SEND AND RETURN
SLATE/TALKBACK/TEST OSCILLATOR
CONTROL ROOM MONITOR
TWO-STUDIO MONITOR
TIMER CONTROL PANEL
ABCD E
METER SWITCHER
REMOTE LINE SELECTOR REMOTE LINE SELECTOR

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BMX SERIES III CONSOLE
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PACIFIC RESEARCH & ENGINEERING
2.3.2 Meter Panel
Figure 2.4 illustrates the layout of the meter panels for the entire range of BMX III consoles. The
AUXILIARY meters are utilized for metering the AUDITION and UTILITY outputs of the BMX III-
10 and BMX III-14 mainframe sizes, and for metering the UTILITY output of the BMX III-18 and
BMX III-22 mainframe sizes. This is accomplished by means of the Meter Switcher Module, which
can also be used to display the Monaural, Send-1, Send-2 or other desired source levels. The
AUXILIARY meters are also used to meter CUE and SOLO signals.
The built-in electret condenser microphone is used as the Control Room source for Slate and Talkback
operations.
NOTE: Blank filler panels are supplied for any unused clock or timer position.
FIGURE 2.4 METER PANEL LAYOUT
CLOCK TIMER
AUXILIARY PROGRAM
PROGRAMAUXILIARY AUDITION
TIMERCLOCK
LEFT RIGHT LEFT RIGHT
LEFT RIGHT LEFT RIGHTLEFT RIGHT
Talkback Microphone
Talkback Microphone
BMX III-10
BMX III-14
BMX III-18
BMX III-22
PACIFIC RESEARCH & ENGINEERING
BMX II I
PACIFIC RESEARCH & ENGINEERING
BMX II I
PACIFIC RESEARCH & ENGINEERING
BMX II I
PROGRAMAUXILIARY AUDITION UTILITY
TIMER
CLOCK
LEFT RIGHT LEFT RIGHT LEFT RIGHT LEFT RIGHT
Talkback Microphone
BMX III-26
BMX III-30
BMX III-34

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PACIFIC RESEARCH & ENGINEERING
2.3.3 Connector Panel
Figure 2.5 (on the following page) illustrates the Molex connector panel for an BMX III-14 console,
and is intended to provide the installer with a map to the location of the various groups of connectors
on the panel. As a general rule, the connectors for any given module are located on the panel behind
that module’s position in the mainframe.
Cutouts are provided for a 24-pin Molex connector for each input position in the mainframe. These are
labeled “OPTION” and are available for the installation of remote control connectors, special purpose
panels,etc. TheOPTION connectors labeled A through EonFigure 2.5 are pre-wired with 24-pinlogic
cables, which are routed to corresponding positions in the mainframe, as defined in Figure 2.3.
Nylon tie anchors are provided along the length of the Molex connector panel for tying down patch
cablesbetween thevariousmodulepositionsandthemeter andmonitorconnectors. Factoryconfigured
consoles will have the appropriate patch wiring in place.
NOTE: Audioand logicpinassignment informationisprovidedinFigure2.6asaquickreferenceonly.
It is highly recommended that the complete information contained in Section 2.7 be used when
connecting the console.