User Guide

Issue 1, August 2010 Model 47 User Guide
Page 28 Studio Technologies, Inc.
Model 72 Interface
And now for a shameless “product plug.”
Studio Technologies, Inc. manufactures
a nifty product called the Model 72 Level
Meter/Interface. A compact, standalone
unit, it can prove very useful when setting
up, maintaining, and troubleshooting inter-
com circuits. It will give a direct indication
of signal levels at any point in a single- or
dual-channel intercom circuit. Check it out!
Specifications
General Audio:
Frequency Response: ±2 dB 100 Hz to 8 kHz
Distortion (THD+N): <0.5%, measured at 1 kHz,
4-wire input to 2-wire interface pin 2
Signal-to-Noise Ratio: >55 dB, measured at 1 kHz,
4-wire input to 2-wire interface pin 2
Connectors:
Inputs from 4-Wire: 3-pin female XLR
Outputs to 4-Wire: 3-pin male XLR
2-Wire Party-Line Intercom: 3-pin male XLR
Remote Control: 10-pin header, requires user-
provided 10-pin ribbon connector assembly
AC Mains: 3-blade, IEC 320 C14 (mates with
IEC 320 C13)
2-Wire Party-Line Intercom Interfaces: 2
Type: 2-channel party-line (PL), unbalanced
(pin 1 common; pin 2 DC with channel 1 audio;
pin 3 channel 2 audio or DC with channel 2 audio)
Compatibility: single- and dual-channel intercom
systems such as from RTS® and Clear-Com®
Impedance, External Power Mode: >10 k ohms
Impedance, Internal Power Mode: 200 ohms
Nominal Level: –10 or –14 dBu, selectable
“Mic Kill” Signal: square wave, 24 kHz, ±1%
2-Wire Party-Line Power Sources:
4, 2 per
interface
Rating: 30 volts DC nominal, 300 milliamperes
maximum, software monitored and controlled
Hybrids: 4, 2 per interface
Topology: 3-section analog circuitry compensates
for resistive, inductive, and capacitive 2-wire party-
line loads
Nulling Method: automatic upon user initiation,
processor implements digital control of analog cir-
cuitry; null settings stored in non-volatile memory
Nulling Line Impedance Range: 120-350 ohms
Nulling Cable Length Range: 0-3500 feet, typical
Trans-Hybrid Loss: >40 dB, typical at 800 Hz
4-Wire Inputs: 4, 2 per interface
Type: transformer-coupled, capacitor isolated
Impedance: 13 k ohms
Nominal Level: 0, +4, +6, or +8 dBu, selectable
in tandem with nominal output level
Maximum Level: +22 dBu
4-Wire Outputs: 4, 2 per interface
Type: transformer-coupled, capacitor isolated
Impedance: 50 ohms nominal
Nominal Level: 0, +4, +6, or +8 dBu, selectable
in tandem with nominal input level
Maximum Level: +20 dBu into 2 k ohms
Meters: 8
Function: displays level of 4-wire inputs and outputs
Type: 5-segment LED, modified VU ballistics
Remote Control Inputs: 3
Type: optically coupled
Input: 3-32 volts DC; 2 milliamperes minimum for
operation, 20 milliamperes maximum
Functions: auto null interface 1, auto null interface 2,
and “mic kill”
AC Mains Requirement: 100-240 volts (–15/+10%),
50/60 Hz, 1.2 amperes maximum @ 100 volts,
0.7 amperes maximum @ 240 volts
Dimensions (Overall):
19.0 inches wide (48.3 cm)
1.72 inches high (4.4 cm)
10.3 inches deep (26.2 cm)
Mounting: one space (1U) in a standard 19-inch rack
Weight: 8.6 pounds (3.9 kg)
Specifications and information contained in this
User Guide subject to change without notice.