4 Ohm / 8 Ohm Input Interface

  • Converts an Amplifier Output to Line Level
  • Bridges 4 or 8 Ohm Speaker Line
  • Adjustable for Wide Range of Input Power Voltage
  • Converts Amplified Levels from 0.5 W to 400 W
  • Excellent Low Frequency Response
  • Suitable to Feed a Subwoofer Amplifier Input
  • Detachable Terminal Block Connections
  • Balanced or Unbalanced Output
  • Superior Quality Audio Transformer
  • Bifilar Windings
  • Galvanic Isolation
  • Convenience of RDL TXs


The TX-8A is the ideal choice in many applications requiring superior quality transformer coupling between the output of a 4 or 8 Ohm power amplifier and the input of an audio mixer or amplifier. A front-panel LEVEL control allows the output to be adjusted for -10 dBV or +4 dBu over a wide range of amplified power levels.

The TX-8A is a single-channel (mono) module featuring barrier block connections for the input and output. A high quality bifilar wound audio transformer couples the audio input to the audio output. The amplified input terminals are isolated from ground. The output ground terminal is connected to the TX-8A metal support structure.

The audio transformer provides galvanic isolation. The secondary may be wired balanced or unbalanced. The TX-8A delivers the wideband audio, low distortion, audio clarity and headroom common to professional equipment in a module suited to general-purpose audio installations.

The excellent low frequency response makes the TX-8A well suited to feed the line-level input of a subwoofer amplifier. In a stereo installation, two TX-8A module output may be mixed to feed a mono audio line and/or a subwoofer amplifier line input.

The TX-8A's compact size permits mounting in a variety of spaces and in various locations in equipment racks. The TX-8A may be mounted where needed, to rack sides or in an equipment rack (either the front or rear rack rails) using a variety of available RDL mounting options. Use the TX-8A individually, or combine it with other RDL products as part of a complete audio/video system.


Input Connector:Barrier block
Minimum Input Level* (for +4 dBu Output):8 W (8 Ohms); 16 W (4 Ohms)
Minimum Input Level* (for -10 dBV Output):0.5 W (8 Ohms); 1 W (4 Ohms)
Maximum Input Level*:400 W
Attenuation Range:16 dB to 34 dB (input to output)
Output Connector:Barrier block
Output Level:-10 dBV unbalanced or +4 dBu balanced, adjustable (10 kOhm load)
Galvanic Isolation:Bifilar wound audio transformer
Frequency Response:20 Hz to 20 kHz (± 0.75 dB)
THD:<0.1% (1 kHz); <1% (20 Hz to 20 kHz)
Power Requirement:Passive
Dimensions:Height: 3.0 in. 7.6 cm Width: 1.2 in. 3.0 cm Depth (case): 1.5 in. 3.8 cm Depth (with connector): 1.8 in. 4.6 cm
*Input level is the voltage that corresponds to a 4 Ohm or 8 Ohm amplifier output
Package Type:Cardboard Box
Tariff code:8543.70.9860
WEEE weight:0.35 lbs.
Package Dimensions:2 x 2 x 4 in.
Shipping Weight:0.41 lbs.

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CAD FilesUnitsFormat
Engineering Functional BlockAmericanDXF
Panel Diagram - FrontAmericanDXF
Panel Diagram - FrontMetricDXF
High Res ImagesFormat
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