The amplifier, under full load sine wave testing, into 8 ohms, both channels driven, delivered 196 watts before clipping. This discrepancy from the target of 200W/channel was caused by rectification losses and greater than expected power supply droop/ripple caused by the power draw of full sine wave testing. In normal listening, music's duty cycle is no where near the strain of this full power test. So in normal operation, the amplifier in fact will supply 200 watts per channel, at less than .005% Total Harmonic Distortion plus Noise. Specific distortion and amplitude measurements:
THD+N at 39.6V RMS, into 8 ohms, delivering 196 watts from 20Hz to 40kHz, with a measurement bandwidth from 10Hz to 80kHz. THD+N hovers near .003% until 4-5kHz, gradually rising to .005% at 20kHz. (Note the Audio Precision Portable One measures itself delivering .0011% distortion in its source signal at 1.27V RMS out).
This plot of distortion versus an output of 2.83 Volts, or 1 Watt, shows distortion hovering around .008-.009%, rising above .01% at 30kHz. The blip at 60Hz is an indicator that more work could be done to reduce mains 60 Hz induced noise and distortion. (Note the Audio Precision Portable One measures itself delivering .0026% distortion in its source signal at 91.73mV RMS out).
This plot of amplitude versus frequency shows flat response out to approximately 50kHz (note that this chart begins at 31.5kHz to make the plot out through 120kHz more visible).
The bulge in output power at 90kHz is an artifact of Two Pole Compensation usage. In empirical testing, it appeared to be no indicator of system instability. Testing with more speaker types should be done however.
Other Performance Data
- SINAD at full power output was measured at 90.2dB with a measurement bandwidth of 80kHz. Noise was measured at 71.6dB.
- SINAD at 2.83V/1 Watt output was measured at 81.1dB with measurement bandwidth of 80kHz. Noise was measured at 70.6dB.
- Intermodulation Distortion: .0026% at 2.83V/1Watt output.
- Input sensitivity: A signal of 91.73mV was required to deliver 2.83V/1 Watts output power. Voltage gain of the amplifier was 29.8 dB.
- Input impedence: 68k Ohm.
- Switch on mute delay: 6 seconds.
- Damping Factor: 59.
- Slew Rate: (to be measured).