Studio Technologies Model 46 Rental Manual
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User Guide Issue 2, September 2007 This User Guide is applicable for serial numbers: M46-00180 and later and units upgraded with software version 1.3 and higher Copyright © 2007 by Studio Technologies, Inc., all rights reserved www.studio-tech.com 50110-0907, Issue 2 This page intentionally left blank. Table of Contents Introduction ................................................................... 5 Installation ..................................................................... 10 Configuration ................................................................ 16 Advanced Configuration ............................................... 18 Operation ...................................................................... 20 Advanced Operation ..................................................... 25 Technical Notes ............................................................. 26 Specifications ................................................................ 28 Appendix A—Interfacing with Telex®/RTS® Matrix Intercom Systems .............................................. 29 Appendix B—Interfacing with Riedel® Artist™ Matrix Intercom Systems .............................................. 30 Appendix C—Interfacing with Clear-Com® Matrix Intercom Systems .............................................. 31 Block Diagram Model 46 User Guide Issue 2, September 2007 Studio Technologies, Inc. Page 3 This page intentionally left blank. Issue 2, September 2007 Model 46 User Guide Page 4 Studio Technologies, Inc. The Model 46 mounts in one space Introduction of a standard 19-inch rack enclosure The Model 46 is designed to interface and requires 100-240 volts, 50/60 Hz for 2-wire full-duplex party-line intercom cir- operation. cuits with 4-wire audio circuits associated with matrix intercom systems. Other spe- 2-Wire Interfaces cialized audio system interfacing applica- The Model 46’s 2-wire interfaces are tions can also be supported. The Model optimized for direct connection with dual- 46 provides two independent full-featured channel party-line (PL) intercom circuits. 2-channel interfaces. Each interface con- In addition, single-channel party-line tains two hybrid circuits which include intercom circuits can also be connected. automatic nulling capability. The analog Many broadcast applications use the dual- circuitry, under software control, provides channel TW-series from Telex®/RTS®, excellent audio quality and high return- including their popular BP325 belt pack. loss. The interfaces are compatible with Other industry-standard single- and dual- powered and unpowered 2-wire party-line channel PL intercom systems, including circuits. They are capable of supplying DC those from Clear-Com®, are also directly power, allowing direct operation of devices compatible. To provide optimal signal such as user belt packs. Configuration set- matching and interface performance the tings allow the 2-wire and 4-wire interface nominal level of the Model 46’s 2-wire circuitry to be compatible with a range interfaces can be selected. Using DIP of nominal signal levels. Audio level me- switches, accessible on the front panel, ters provide user confirmation of system the nominal levels can be selected to be performance during setup and operation. either –10 or –14 dBu, settings that should Applications for the Model 46 include tele- allow compatibility with virtually all party- vision sports and special event broadcast- line systems. For example, for applications ing, theme park and theater installations, that use equipment from RTS the –10 dBu corporate events, and industrial testing setting is appropriate. For other equip- environments. Standard audio connectors ment, such as that from Clear-Com, the are used for all input and output signals. –14 setting is correct. Model 46 Front Panel Model 46 Back Panel Model 46 User Guide Issue 2, September 2007 Studio Technologies, Inc. Page 5 The Model 46’s 2-wire interfaces can intercom power source ensures that sys- correctly function with powered (“wet”) tems requiring long intercom cable runs or unpowered (“dry”) intercom circuits. will function correctly. The circuitry’s out- Powered circuits have a DC voltage pres- put regulation is such that little change in ent, typically provided by power supplies the output voltage will occur over its entire such as the RTS PS31 or Clear-Com rated output current. Also, the unique de- PS-232. This DC power, normally 30-32 sign of the power supply circuitry virtually volts, provides energy for connected eliminates the noise and “hiss” associated devices such as user stations or belt with typical intercom power supply perfor- packs. In this type of application the mance. Under software control the output Model 46 is configured to operate in its of the DC power supplies are monitored external 2-wire power source mode. In this for over-current and short-circuit condi- mode the Model 46’s circuitry maintains tions. This allows protection shut-down the required high-impedance load and, of the output DC, as well as providing an as in all cases, draws no power from the alert by way of a visual indicator. party-line circuit. An auto-terminate func- tion ensures that should a “wet” circuit not Analog Hybrids with Auto be connected, the Model 46’s interface Nulling circuitry will remain stable. This unique feature makes certain that objectionable A key reason that the Model 46’s inter- audio signals, including oscillations and faces achieve excellent audio performance “squeals,” will infrequently be sent to the is the design of the 2-wire-to-4-wire hybrid connected 4-wire device. circuits. They provide low noise and dis- tortion, good frequency response, and A significant capability of the Model 46’s high return-loss (“nulling”), even when 2-wire interfaces is their ability to supply presented with a wide range of 2-wire DC power and 200 ohm AC termination conditions. Unlike telephone-line (“POTS”) to the connected intercom circuits. Re- oriented DSP-based hybrid circuits, the ferred to as the Model 46’s internal 2-wire Model 46’s analog circuitry provides ex- power source mode, the 30 volt output tended frequency response. With a pass can power devices such as user stations band of 100 Hz on the low-end and 8 kHz and belt packs. In many applications this on the high-end, natural-sounding voice will eliminate the need for external inter- signals can be sent to, and received from, com power supplies. Besides reducing the 2-wire party-line circuits. total system cost, this feature can also lower system weight, reduce required A hybrid’s ability to isolate the transmit mounting space, and decrease the mains signal from the receive signal in the 2-wire- energy requirement. to-4-wire interface is critical. The quality of this isolation, technically known as With each 2-wire interface’s ability to sup- return-loss or trans-hybrid loss, is mea- ply up to 300 milliamperes of current, a sured in dB. A high value is important, typical broadcast application that uses two especially in applications where multiple sets of three BP325 belt packs can easily 2-wire-to-4-wire interfaces are used togeth- be supported. Each interface’s 30 volt DC er. Remote sports broadcast applications Issue 2, September 2007 Model 46 User Guide Page 6 Studio Technologies, Inc. are especially sensitive to this requirement. 4-Wire Interfaces The Model 46’s sophisticated auto nulling Associated with the 4-wire portion of the function uses analog circuitry under mi- Model 46’s interfaces are analog line-level croprocessor control to achieve significant inputs and outputs. These are intended trans-hybrid loss. This return-loss “null” is to interconnect with a variety of 4-wire de- achieved by making a series of adjustments vices, including matrix intercom systems, to account for the resistive, inductive, and audio-over-fiber transmission systems, capacitive conditions that are present on and other specialized audio equipment. the connected 2-wire party-line circuit. The The input and output circuitry is transform- party-line’s conditions are the sum of the er-coupled to minimize the chance of impact made by the type and quantity of hum, noise, or ground “loop” issues. cable, the connected user-devices, and A key characteristic of the Model 46’s de- the intercom power source. sign is the ability to select the 4-wire input Whenever a user presses one of the Model and output nominal levels. This helps to 46’s “auto null” buttons digital circuitry ad- ensure compatibility with virtually all audio justs the analog hybrids to rapidly achieve equipment. Front-panel-accessible DIP their maximum return-loss. The nulling pro- switches allow the nominal levels to be cess takes less than 10 seconds for each configured from among four choices: 0, channel of an interface. However, it’s impor- +4, +6, or +8 dBu. The 0 dBu setting was tant to note that while the nulling process specifically provided for compatibility with is automatic, it only takes place upon user Clear-Com matrix intercom systems. The request. This can lead to more stable and +4 dBu setting allows “standard” audio consistent audio performance when a hy- signals to be directly connected. Digital brid is exposed to the varying 2-wire condi- matrix intercom systems from Riedel® can tions often found in broadcast applications. be effectively connected using the +6 dBu The parameters obtained during the nulling setting. And the +8 dBu setting allows process are stored in non-volatile memory; proper level matching with the popular mains power interruptions won’t require