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Sonifex HY-03T - Twin Automatic Analogue TBU, Rack Mounted

by Sonifex
£1,751.94 inc. vat
£1,459.95 ex. vat
Please contact us for availability.

Sonifex HY-03T

The Sonifex HY-03T is a twin 1U rackmount automatic analogue TBU. Telephone hybrids, or telephone balance units (TBUs) provide the interface between professional audio equipment and the public telephone network. They provide protection for your equipment and the public telephone lines, allowing for varying line signals and line conditions. Automatically cancelling out the unwanted signal they also facilitate two-way communication down a single telephone line.

The analogue Sonifex HY-03 telephone hybrid is the replacement for the HY-02, which for many years has set the standard as an excellent value, high quality telephone hybrid.

The HY-03 retains many of the features of the HY-02 and adds some additional ones. Some of the features of the HY-03 include :

  • Fully automatic - adapts to varying line conditions and has automatic signal limiting.
  • Local and remote line hold switching - calls can be remotely switched through a mixing console.
  • Momentary or permanent latching remotes can be enabled.
  • Balanced mic/line input - 10k ohm balanced input selectable for 0dBu clean feed line, or microphone level with adjustable gain.
  • Balanced output - 0dBu low impedance balanced output, with output gain adjustment.
  • Mixed output - the output can be a mix of the caller and mic/line input signals for recording both sides of the telephone conversation.
  • Integrated ring detector - automatic call answering after a pre-determined number of rings.
  • Fitted with K-break disconnect detection as standard with an option for dial-tone disconnect using the optional HY-03DTD board. The HY-03DTD board can be configured to disconnect on recognizing the dial tone used in a specific country.
  • Line limiter, bandpass filter and output noise gate with preset threshold providing low distortion crystal clear audio.
  • 28dB typical line balance rejection.
  • Built in power supply with switchable 115V, or 230V, mains input.
  • BABT approval compliant with European PTT specifications.

Sonifex HY-03T Specifications

Audio Specification

  • Input Impedance - Line Mode (Clean Feed): 10kΩ balanced 0dB
  • Input Impedance - Microphone Mode: 200Ω balanced
  • Clean Feed Limiting Input: +4dBu
  • Microphone Level Range: From 74dB to 40dB adjusted by preset pot
  • Bandwidth to Telephone Line: 250Hz - 4kHz, -3dB ref 1kHz
  • Telephone Line Impedance: Nominally 600Ω
  • Telephone Line Impedance Range: 300Ω to 1500Ω
  • Output Impedance: 50Ω balanced floating 0dBu
  • Output Level Range: +8dB to -14dB adjusted by preset pot
  • Rejection Ratio: 45dB on 1kHz tone, typically 28dB on complex waveforms, reference peak level of 0dB
  • Ring Detector Sensitivity: 1 ring to 6 rings
  • Power: 230V 50Hz, or 115V 60Hz. 6W for HY-03.   


  • Mic/Line Input: XLR 3 pin female with push button mic/line selection
  • Line Output: XLR 3 pin male
  • Telephone Line: RJ11 6/4 socket
  • Telephone Handset/Instrument: RJ11 6/4 socket
  • Remotes: 9-way D-type socket
  • Power: IEC mains (CEE22)

Each unit is supplied with 1 x RJ11 to RJ11 telephone line lead, 1 x RJ11 to BT plug telephone line lead, 1 x BT handset socket to RJ11 plug adapter, IEC mains lead fitted with moulded mains plug, handbook and warranty card.