QSC PTL-1 Pilot Tone Load



Within Q-SYS, a 22 kHz pilot tone (outside the audible range of human hearing and undetectable above the program material) is transmitted along each loudspeaker line. Q-SYS, knowing the impedance value of the PTL-1, is then able to easily detect any deviation in the impedance at 22 kHz.

Any significant drop below a predetermined impedance will signify that a short circuit has occurred, while any rise above signifies that an open circuit has occurred. Each failure scenario will then generate a time stamped event into the Q-SYS Event Log, which may then trigger alert messages if desired.
Additionally, the user can select whether the pilot tone is only generated during a scheduled maintenance check, or whether the tone is always active to provide real-time diagnostics on every zone.


  • Pilot tone detection on 70V or100V loudspeaker circuits using QSC DataPort and CXD platform amplifiers
  • Ceramic screw-down connector block
  • Fuse protects circuit against shorts
  • Versatile install adapter plate included
  • Fits most plenum-rated electrical boxes