The RDL TX-1A Adjustable Line Transformer provides transformer-isolated conversion from a balanced line-level audio source to an unbalanced audio input. Designed for professional AV, commercial sound, and broadcast installations, the TX-1A helps connect equipment with different audio connection formats while providing adjustable signal attenuation.
The TX-1A is particularly useful when connecting a professional mixer, digital signal processor (DSP), or other balanced audio source to an amplifier, receiver, or device with an unbalanced line-level input.
Its built-in level adjustment allows the output signal to be reduced from 4 to 24 dB below the input level, helping prevent excessive input levels when interfacing professional and consumer audio equipment.
Transformer isolation also helps reduce hum and noise associated with ground loops between connected devices.
The compact RDL TX-Series design makes the TX-1A suitable for permanent installations in equipment racks, AV cabinets, and other locations where space is limited. As a passive transformer interface, it requires no external power supply.
RDL TX-1A Key Features
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Balanced to Unbalanced Conversion: Interfaces a balanced line-level audio source with an unbalanced line-level input.
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Transformer Isolation: Provides electrical isolation to help reduce ground-loop hum and unwanted noise.
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Adjustable Output Attenuation: Trimpot adjusts the output from 4 to 24 dB below the input level.
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Selectable Input Termination: Supports 10 kΩ bridging or 600 Ω terminated input operation.
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Wide Frequency Response: 20 Hz to 20 kHz (±0.5 dB).
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Low Distortion: Less than 0.05% THD at 1 kHz.
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Passive Operation: No external power supply required.
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Compact TX-Series Housing: Convenient for commercial AV and custom equipment installations.
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Single-Channel Audio Interface: Designed for one balanced-to-unbalanced audio signal path.
Connecting Professional Audio Equipment to Unbalanced Inputs
Many professional audio mixers, processors, and DSP systems use balanced line-level outputs, while consumer amplifiers, receivers, and other equipment may have unbalanced inputs.
Connecting these devices directly can sometimes create signal-level mismatches or introduce unwanted hum.
The RDL TX-1A provides a practical interface between these two types of audio equipment.
Its adjustable attenuation allows installers to reduce a higher-level professional audio signal before it reaches the unbalanced input.
This is particularly helpful when integrating professional audio equipment into existing commercial sound systems.
Transformer Isolation for Reduced Ground-Loop Noise
The TX-1A uses transformer isolation between its balanced input and unbalanced output.
This isolation can help reduce hum and buzz caused by ground-potential differences between connected audio components.
Unlike a simple wiring adapter, the TX-1A provides electrical isolation while maintaining a wide audio frequency response.
The result is a practical solution for audio installations where balanced and unbalanced equipment must operate together.
Adjustable Output Level for Better Signal Matching
The TX-1A includes an adjustable level trimpot that provides output attenuation ranging from 4 to 24 dB below the input level.
This allows installers to match the output of a professional audio device to the input sensitivity of downstream equipment.
The input can also be configured for 10 kΩ bridging or 600 Ω terminated operation, providing flexibility when connecting different types of line-level audio sources.
RDL TX-1A Technical Specifications
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Specification
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Details
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Manufacturer
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Radio Design Labs (RDL)
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Model
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TX-1A
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Product Type
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Adjustable balanced-to-unbalanced line transformer
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Audio Channels
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1 (mono)
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Input
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Balanced line level
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Output
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Unbalanced line level
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Output Adjustment
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4 to 24 dB below input level
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Input Configuration
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10 kΩ bridging or 600 Ω terminated
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Frequency Response
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20 Hz–20 kHz (±0.5 dB)
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Total Harmonic Distortion
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Less than 0.05% at 1 kHz
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Isolation
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Transformer
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Power Requirement
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None — passive operation
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Width
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1.2 in. (3.0 cm)
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Length
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3.0 in. (7.6 cm)
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Height
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1.4 in. (3.6 cm)
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Shipping Weight
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0.305 lb
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Recommended Applications
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Commercial AV Systems: Connect balanced DSP or mixer outputs to unbalanced amplifier inputs.
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Restaurants and Retail Stores: Integrate professional background music equipment with existing audio components.
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Houses of Worship: Interface professional mixers and audio processors with unbalanced equipment.
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Broadcast and Production: Provide transformer isolation between compatible line-level devices.
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Conference Rooms: Reduce potential ground-loop problems when connecting different audio systems.
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Custom Audio Installations: Provide adjustable signal attenuation in compact equipment spaces.
Important Installation Considerations
The TX-1A is designed for line-level audio signals and provides a single balanced-to-unbalanced audio channel.
For stereo installations, two independent audio channels must be accommodated.
The TX-1A does not amplify signals or convert speaker-level outputs to line level. Its output adjustment only reduces the incoming audio level.
Why Buy the RDL TX-1A from Audio Supply?
Audio Supply offers RDL audio interface products for professional and commercial installations. We can help you select the appropriate transformer, converter, or signal interface for your system.
Need a Compatible Mounting Accessory?
The RDL TX-1A can be installed using compatible TX-Series mounting accessories, including the RDL MB-1 mounting kit and DRA-35T DIN rail adapter.
Contact Audio Supply for help selecting a suitable mounting solution for your installation.
