Yamaha P-2200 - Manual (Page 13)

The following are actual oscilloscope photographs
made by an independent testing laboratory. The close
vertical alignment of input and output traces in Fig. 21
through 23 depicts very low phase shift, so the amplifier
will not alter musical wave shapes.
Fig. 21 - 10Hz Square-Wave Response
The output waveform displays very respectable
low frequency response. The slight "tilt" shows
a DC gain of unity, which prevents damage to
speakers in the event any DC offset is fed to the
amplifier input.
Fig. 22 - 1,000Hz Square-Wave Response
Near-perfect response is evident in the duplica-
tion of the input waveform by the output wave-
form. There are no "squiggles" or spikes, mean-
ing there Is no ringing or overshoot.
Fig. 23 - 20,000Hz Square-Wave Response
The extremely fast and symmetrical rise and
fall times of the amplifier are evident, demon-
strating the ability to accurately reproduce
musical waveforms and harmonics well beyond
the range of human hearing.
Fig. 24 - 1,000Hz Sine Wave, shown with Highly-
Magnified Noise and Distortion Components
Even at full 230 watt output (8-ohms), the
P-2200's distortion is so low that it is almost
burried in the noise, which is at least 110dB
below the sine wave output. The sine wave is
clean and symmetrical.
Fig. 25-20,000Hz Sine Wave, shown with Highly-
Magnified Noise and Distortion Components
While no amplifier should ever have to pro-
duce 230 watts continuous output at 20kHz,
the P-2200 does it with low distortion, and
symmetrical reproduction. As In Fig. 1 1 , the
noise (magnified here) is actually better than
110dB below the sine wave.
Fig. 26 - Square-Wave Response into a Highly-
Inductive Load (at 1kHz)
The ability of the P-2200 to maintain a
sharply defined square wave output into a
reactive load demonstrates stability under the
worst conditions. There is still a complete lack
of unwanted ringing, as well as low phase shift.
Fig. 27 - Unit-step Function Response