FirstWatt SIT-2 Manual page 7

This wide bandwidth is also reflected in the square wave response of the amplifier, here
shown at 20 Khz. The rise times are very fast, and there is no ringing or overshoot.
Lastly, a plot of the distortion of the amplifier versus frequency shows a consistent character
across the audio band:
This consistency of performance over the audio band is an important element to the sonic
character of the SIT-1 and SIT-2. The frequency and phase response is flat, distortion
harmonics are consistent in amplitude and phase relationship, and the damping factor
remains the same.