SMD DD-1 Distortion Detector 
The purpose of this tool is to enable the installer to set the gain of an audio amplifier to match the source unit’s output level, accurately and quickly. It can also be useful for detecting distortion in the audio signal caused by poorly designed or malfunctioning audio equipment.
What Is Included?
The Distortion Detector (DD-1))
Protective silicon rubber boot
Calibrated Test tone CD
Harness
This manual
Pride of ownership
 
Specifications
Everyone hides these in the back of the book. We are proud of our specs, they aren’t lies, so we are putting them up front.
The Distortion Detector’s circuitry is 100% analog
Distortion Detection trigger level > 1.0% Harmonic Distortion
Guaranteed operating range of input signal is 1.2Vrms – 125Vrms. (15,000 Watts at 1 ohm) Autoranging
Signal Present LED trigger voltage 750mVrms
Low Battery LED trigger battery voltage < 5.6Vdc
Auto-shut off timer 8 - 10 minutes after ON button is pressed