- Written by John E. Johnson, Jr.
- Published on 13 February 2012
The Pass Labs X1000.5 Power Amplifier On the Bench
At 1 kHz, 5 volts into 8 Ohms, distortion was a paltry 0.005%.
At 20 volts (50 watts) output, distortion actually decreased (however, I consider this difference insigificant). Notice that the odd ordered harmonics predominate.
The B-A peak (1 khz) from using 19 kHz and 20 kHz sine waves as the test signal, was 95 dB below the fundamentals. Notice also that the base of the 19 kHz and 20 kHz peaks is relatively clean.
IMD at 50 watts output was 0.004%. This is terrific performance.
THD+N vs. Frequency for a 50 watt output (8 Ohms) shows distortion staying below 0.02% to about 5 kHz, and a rise to just under 0.1% at 20 kHz.
THD+N vs. Power indicates that the X1000.5 outputs 1,000 watts into 8 Ohms at clipping (1% THD+N). In this graph, the 1% mark is crossed at about 950 watts, but this was due to the wall AC voltage dropping significantlly with such high power demand. There is no question that this amplifier will output at spec.
The measured Frequency Response was 10 Hz - 20 kHz ± 0.1 dB.