Mark Levinson No.383 integrated amplifier Measurements part 3

Fig.8 shows the continuous output power with both channels driven into 8 ohms and 4 ohms. (When I tried this test into 2 ohms, the No.383 muted and displayed the message "Amp Fault" on its front panel.) The Levinson comfortably exceeds its specification, giving 145W into 8 ohms (23.9dBW) and 230W into 4 ohms (20.6dBW), both at the standard 1% THD+noise definition of clipping.

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

Mark Levinson
2081 South Main Street
Middletown, CT 06457
(860) 346-0896