- Written by Ross Jones
- Published on 22 June 2009
On the Bench
All distortion measurements were made within an 80 kHz bandwidth and with two channels driven, and except where indicated, into 8 ohm loads.
At 1 kHz and 20 volts output into 8 ohms, THD+N was 0.01%.
IMD at 20 volts was 0.009%.
THD+N vs. Frequency showed a large rise above 1 kHz, and especially at 4 ohms, began to approach 1%. Because of this, I would suggest using 8 ohm speakers.
THD+N vs. Power output is shown below. At 8 ohms, distortion began to rise sharply at 150 watts, then clipped (1% THD+N) at 180 watts. (The point at where the line bends sharply, in this case at 150 watts, is the practical output limit.) At 4 ohms, the sharp bend occurs at 185 watts, with clipping at 250 watts.
The measured frequency response was 20 Hz - 60 kHz, - 1 dB.