General Description

The Shure A15TG Tone Generator is a battery-powered 700 Hz signal source that can be used to troubleshoot low-impedance, balanced-line microphone inputs.

The A15TG includes a recessed On-Off switch and a three-pin XLR audio connector. A removable end cap allows easy battery installation and removal. The A15TG can also tolerate the presence of phantom power, or a short circuit in the line it is driving. Built-in short circuit protection allows normal operation to resume after a short is removed.

Battery Life

The A15TG can operate continuously for approximately 1000 hours on one 1.5V alkaline battery (see battery specification for suggested types). To conserve battery power, make sure the On-Off switch is in the Off position when the A15TG is not in use.

Battery Installation

  1. Unscrew the end cap.
  2. Insert the battery with the "+" terminal facing the "+" mark inside the end cap.
  3. Reinstall the end cap.


Output Frequency

700 Hz +20%, when terminated with 150 Ω

Output Level

-41.5 +4.5 dBV (8.4 mV typical) when terminated with 150 Ω

Total Harmonic Distortion

5% typical for any output termination greater than or equal to 150 Ω

Output Impedance

>15 Ω

Battery Type

1.5 V (such as A76 alkaline, 357 silver oxide or 675 zinc-air hearing aid battery)

Temperature Range

Operating Temperature -12°C to 50°C (10°F to 130°F) -29°C to 74°C (-20°F to 165°F)


Steel with gray enamel finish


19  mm (.75in.)diameter; 141  mm (5 17/32 in.) long