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Model 33A Talent Amplifier

The Model 33A Talent Amplifier is a self-contained listen-only "beltpack" unit intended for use by on-air talent or production personnel. It's directly compatible with the Studio Technologies' Model 2A Central Controller as well as other standard IFB or party-line intercom circuits. The Model 33A is powered by, and receives audio from, the connected IFB or intercom circuit. A single 3-conductor microphone-type cable links the Model 2A's talent amplifier output with the Model 33A's input. Each Model 33A contains both a male and a female 3-pin XLR-type connector, allowing simple "loop-through" connection of multiple units. Up to four talent amplifiers can be connected to, and powered by, a single Model 2A Central Controller. The Model 33A's output is intended to be connected to talent earpieces or headsets. For flexibility the audio output is provided on both ¼-inch and 3.5 mm jacks. An LED indicator lights whenever input power is present, providing setup assistance and user confidence. The Model 33A is housed in a lightweight, yet rugged, aluminum housing. A belt clip allows it to be directly attached to clothing or accessories. An optional mounting adapter is available to allow the Model 33A to be installed in a permanent location.

Key Features
Controls allow mix of Channels 1 and 2
¼-inch and 3.5 mm output connectors
Excellent audio quality
Low DC power consumption
Compatible with Model 2A Central Controller
Compact, lightweight package
Update of the popular Model 33

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Product Information & Images
Files listed here are the most-recent issues unless otherwise noted; full history product information can be found on the Documentation page.
Data Sheet
User Guide (included in IFB Model 2A User Guide)
Block Diagram

Model 33A Talent Amplifier

Model 33A Talent Amplifier Front and Back Views

Talent Amplifier Mounting Adapter Kit

Optional Talent Amplifier Mounting Adapter Kit

Talent Amplifier Mounting Adapter Kit shown mounted on Model 33A

Model 33A Talent Amplifier shown with optional Mounting Adapter Kit


The Model 33A is unique in that a "mix" of IFB channels 1 and 2 can be created. Two level controls, along with a source select switch, allows camera and production personnel to hear IFB cues from either or both channels. This allows IFB signals intended for both technician and talent to be simultaneously monitored. By design, the Model 33A's level controls cannot be set to fully attenuate ("mute") the audio output. This helps to minimize the chance that users will accidentally miss important "cues" from directors or producers. While audio quality is not normally considered a factor in IFB or intercom systems, the Model 33A is built to "pro audio" standards. This helps to ensure that the best possible audio reproduction is provided.

The Model 33A is an update of the popular Model 33 Talent Amplifier. The Model 33A includes the addition of a 3.5 mm output jack, along with updated internal circuitry. In all ways the Model 33A meets or exceeds the performance of its predecessor.

The Model 33A is compatible with virtually every standard IFB and party-line intercom circuit, including those associated with equipment from RTS®, Clear-Com®, and Studio Technologies. This type of circuit typically uses a 3-pin XLR-type connector for interfacing with connected equipment. Electrically, XLR pin 1 serves as common for DC power and audio; pin 2 provides DC power and, in the case of a dual-channel circuit, DC power and channel 1 audio; pin 3 provides channel 2 audio for dual-channel systems, or channel 1 audio in single-channel systems.

Applications: directly compatible with talent amplifier output on Model 2A Central Controller; also compatible with standard single- and dual-channel IFB and party-line intercom circuits
Indicator Light: red LED indicates operation of internal power supply
Input: 3-pin female XLR
Loop Through: 3-pin male XLR
Output: ¼-inch and 3.5 mm 2-conductor jacks; sleeve common, tip "hot," ring not used
IFB/Intercom Input Wiring Scheme:
Pin 1: common for DC and audio
Pin 2: DC with channel 1 audio (dual-channel circuits) or DC only (single-channel circuits)
Pin 3: channel 1 audio (single-channel circuits) or channel 2 audio (dual-channel circuits)
Power Requirement: 18-35 Vdc, 15 mA quiescent, 40 mA maximum
Compatibility: intended for connection to mono (2-conductor) headsets or earpieces with nominal impedance of 150 ohms or greater
Type: voltage driver
Input/Output Gain: 28 dB, maximum
Maximum Output Voltage: 8 Vpp, 1 kHz, 150 ohm load
Frequency Response: 40 Hz-20 kHz, ±1 dB, 150 ohm load
Distortion (THD+N): 0.03%, 1 kHz, 150 ohm load, 0 dBu out
Dimensions (Overall):
3.25 inches wide (8.3 cm)
1.8 inches high (4.6 cm)
3.95 inches deep (10.0 cm)
Mounting: intended for portable applications; contains integral belt clip; optional mounting adapter kit allows Model 33A to be permanently mounted
Weight: 0.6 pounds (0.3 kg)

Specifications subject to change without notice.