Mark Levinson No.383 integrated amplifier Measurements part 3
Fig.8 Mark Levinson No.383, distortion (%) vs continuous output power into (from bottom to top at 2kHz) 8 ohms and 4 ohms.
Repeating this test with one channel driven using a low-duty-cycle 1kHz toneburst of 10 cycles on, 400 cycles off—this better approximates a music signal—revealed the No.383 to be a powerhouse (fig.9). No less than 182.6W were delivered into 8 ohms with this signal (black trace) at clipping (horizontal magenta line). The 4 ohm delivery was 356W (red trace), the 2 ohm delivery 665W (blue)! Only into the punishing 1 ohm load did the amplifier falter, its output at clipping dropping to 75W (green trace), with a significant rise in distortion below that power.
Fig.9 Mark Levinson No.383, distortion (%) vs 1kHz burst output power into 8 ohms (black trace), 4 ohms (red), 2 ohms (blue), and 1 ohm (green).
But Madrigal doesn't specify the No.383 for continuous output into loads lower than 4 ohms. If you want an amplifier to behave as a voltage source down to 1 ohm, you should consider buying one of their separate power amplifiers.—John Atkinson