SMD Distortion Detector DD-1 HV (High Voltage) The Distortion Detectors circuitry is 100% analog Distortion Detection trigger level &gt; 1.0% Harmonic Distortion Guaranteed operating range of input signal is 1.2Vrms  200Vrms. (40,000 Watts at 1ohm) Autoranging Signal Present LED trigger voltage 750mVrms Auto-shut off timer 8 - 10 minutes after ON button is pressed