BURK Technology LX-1 User manual

LX-1
Stereo Selector
INSTRUCTION MANUAL
7 Beaver Brook Road
Littleton, MA 01460
[phone]
FAX [phone]
Copyright 1992-1997 by Burk Technology, Inc.
REV A

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Contents
Section One Features..............................................................
... 5
INTRODUCTION Matching Standard
Levels.................................... 6
Controls..............................................................
.. 7
Warranty.............................................................
.. 7
Section Two General...............................................................
... 8
INSTALLATION Memory..............................................................
.. 8
Connectors..........................................................
.. 8
Audio
Wiring........................................................ 9
Recommended
Practices....................................... 10
Connecting Unbalanced Sources.......................... 10
Setting Audio
Levels............................................ 11
Setting Alternate
Jumpers..................................... 12
Audio
Outputs...................................................... 13
Audio Output
Connectors..................................... 14
Deriving
L+R........................................................ 15
Control Connector
Wiring.................................... 16
Remote Control
Connections............................... 17
Logic Output Connection to External Devices..... 18
Section Three READY
Mode...................................................... 19
OPERATION Select Alternate
Mode.......................................... 19

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MIX
Mode............................................................ 20
Bar Graph
Display................................................ 20
Section Four Audio
Board......................................................... 21
TECHNICAL DESCRIPTION Display
Board....................................................... 23
Logic
Board.......................................................... 24
Section Five Table of
Contents................................................. 27
DOCUMENTATION Schematics..........................................................
.. 28
Parts
Location....................................................... 36
Printed Circuit Board X-Ray Views..................... 38
Parts
List............................................................... 41

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Section One
INTRODUCTION
Features
•Select or mix from six stereo input sources.
•Control and read the status of the unit from the front panel, through the individual source
connectors on the rear panel, or by remote control.
•Control cart, tape and satellite feeds with machine-follow audio.
•Match input levels of -10, 0, +4 or +8dBu. (Note: In this manual levels are expressed as dBu,
except where a 600Ωload is known to exist.)
•Use the LOOP function to switch a processor in/out of the program path. Monitor program
level on the dual 12 segment bar graph display.
•Distribute identical MAIN and SUB out-puts.
•Prevent accidental switching by locking out all control functions with the “safe” mode.
The Burk Technology LX-1 Stereo Selector simplifies and improves studio and transmitter
systems by providing elegant selection and mixing of program sources. Featuring quality;
flexibility and easy to use, the LX-1 can serve a number of station needs.
Designed to be the final “gateway” for broadcast systems, the LX-1 can serve as the hub of a
multi-studio complex, or as the switching center for satellite, network and studio feeds. As a
master control switcher, it can be controlled from a central point, by remote control, or from each
studio it serves. Where desired, each studio can have its own air control and ON-AIR indicator.
Low cost, ease of interface and machine-follow audio capability make the LX-1 a good choice as
a console input extender, or as a switcher for automation or production systems.
The usefulness of the LX-1 is enhanced by full remote control capability, external processor
switching, a SAFE mode and memory retention during power loss.
With the LX-1 you can:

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Switching Quality
High Noise Rejection From all Sources
Matching Standard Levels
With the coming of the LX-1 it is time to do away with outmoded patch cords and relays. The
Burk LX-1 provides versatile and foolproof operation and a cleaner audio path.
The LX-1 sets new standards for switcher audio performance. It uses noiseless “soft” switching to
give clean program transitions. Instead of the “chopping” action of relays, switches, patch cords
and typical electronic switchers, the LX-1 makes a controlled transition from one source to the
next. The turn-on and turn-off transitions are never audible as such. The audio simply appears or
disappears. This effect is particularly impressive when working from live or digital sources. Clean
audio appears out of dead silence.
When a channel is turned on, its audio is passed through the LX-1 with very low distortion,
typically a few thousandths of a percent. When a channel is switched off, the LX-1 yields typically
100 dB of isolation. This assures there will be no audible noise or crosstalk from fast forwarding
of tape or hot inputs. Off is OFF.
Not only is the LX-1 a very low-noise device, its extraordinary 100dB common-mode rejection
will reduce hum and noise from ground loops and station cabling. An important design goal was
achieving high noise rejection from unbalanced sources such as consumer CD and DAT machines.
This performance, and the ability to accept typical “HI-FI” levels, makes the LX-1 the best way to
integrate consumer and semi-professional equipment into a studio environment.
It is recommended practice to calibrate all distribution signals to a standard level, typically +4
dBu. Unfortunately, manufactures do not always adhere to standards. For example, a cart
machine may be designed for “0” output level. Jumpers on the LX-l’s audio board for each
channel may be set to standard levels of-10, 0, +4 and +8 dBu.

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Controls Displays and Connectors
•Audio board and power supply
•Logic board
•Display board
Warranty
The front panel switches (READY, LOOP, MIX and channels 1-6) have built-in status lights. The
dual 12-segment three color program level displays feature peak-hold on the upper five segments.
The LX-1 uses convenient Mini Combicon connectors that require only a screwdriver for
assembly. No crimping, soldering or special tooling is needed.
The rear panel has audio and control connectors for each of the six inputs as well as MAIN-SUB
and LOOP audio outputs. The LX-1 output stages more closely simulate high quality output
transformers than typical designs and will drive high levels into complex loads, such as long audio
lines and complex studio wiring.
Full remote control capability is provided through the ‘A” and “B” remote control connectors on
the rear. As an added convenience, power is provided for lighting LEDs for external status
indication.
The LX-1 circuitry is contained on three circuit boards:
Burk Technology warrants the LX-1 to be free of defects in materials and workmanship for a
period of 24 months from the date of purchase. Equipment will be repaired or replaced at the
option of Burk Technology and returned freight prepaid to the customer. Damage due to abuse or
improper operation or installation of the equipment or caused by fire or flood or harsh
environment is not to be covered by this warranty. Damage in shipping is not the responsibility of
Burk Technology A return authorization must be obtained before returning any equipment.
Materials returned under this warranty must be shipped freight prepaid and insured in the original
shipping carton or suitable substitute to Burk Technology
Repairs not covered under this warranty will be made at prevailing shop rates established by Burk
Technology.
THE WARRANTY SET FORTH ABOVE IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. BURK
TECHNOLOGY SHALL NOT BE LIABLE TO ANY PARTY FOR ANY INCIDENTAL,
SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES ARISING FROM THE USE OF
THIS EQUIPMENT

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Section Two
INSTALLATION
General
Memory
Connectors
CAUTION
Carefully unpack the LX-1 and save the packing material. The LX-1 should be installed in a well-
grounded equipment rack. High common-mode rejection, good case shielding and general
immunity to RF and magnetic fields make installation easy; however, good engineering practices
should be followed. The LX-1 and audio lines should be kept away from large power
transformers, RF generating devices and equipment that may produce inductive line transients.
The filtered power entry module and a well isolated toroidal power transformer contribute to
freedom from electrical noise.
Unless otherwise requested and marked, the LX-1 is wired for operation at 117 vac nominal,
50/60 Hz; 30 watts. The toroidal power transformer allows operation from UPS or inverter. See
the power supply schematic, page 37, for 230 volt strapping.
The LX-1 has memory retention that should be adequate for normal station shutdowns and power
outages; however, it is best not to power it from a switched power source. The best practice is to
leave the unit powered continuously If power is off too long, the LX-1 will reset all functions to
off and default to “safe.”
The LX-1 uses Mini Combicon connectors. These simplify installation and wiring changes. The
connectors are actually removable terminal strips. Wire strippers and a small blade screwdriver are
the only tools needed to attach the connectors.
The LX-1 uses six and twelve pin connectors for both audio and control functions. It is imperative
that plugs (removable terminal strips) are inserted into the correct rear panel connectors.
Interchanging audio and control connectors, especially the remote control connectors, can
damage the LX-1 and external devices.

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Figure: 1 Input connectors
We recommend labeling each plug connected to the LX-1 . A “Sharpie” marking pen is ideal for
this purpose.
The top row of 6-pin rear panel connectors are for channel control. They provide Ready tally,
channel ON indication, start and stop pulses and permit channel selection. The two 12-pin
connectors on the top row permit full remote control.
The audio connectors are located along the lower portion of the rear panel. The six 6-pin
connectors are the channel audio inputs and the two 12-pin connectors are for program output
and Loop functions.
PIN #1Pin #1 of all connectors is located to the left. See figure 1.