McIntosh Labs MC2000 power amplifier Measurements part 3
Fig.9 McIntosh MC2000, distortion (%) vs continuous output power into (from bottom to top at 2kHz) 4 ohms, 8 ohms, and 2 ohms (matched impedance taps).
Table 1 McIntosh MC2000 Clipping(1% THD+noise at 1kHz)
|Both Channels Driven||One Channel Driven|
|W (dBW)||W (dBW)|
|8||162 (22.1)||164.3 (22.16)||172.2 (22.36)|
|4||165.5 (19.19)||164.9 (19.17)||176.8 (19.47)|
Using the Miller Audio Research Amplifier Profiler to examine the McIntosh's power capabilities using a low-duty-cycle 1kHz toneburst with one channel driven, John Atkinson found it be a powerhouse. Matching the tap to the load gave around 200W at 1% THD+N. But almost the same power was available into lower impedances. Fig.10, for example, shows that while the 4 ohm tap will deliver 139W into 8 ohms and 205W into 4 ohms, it will still output 199W into 2 ohms and even 107W into 1 ohm, the latter equivalent to an RMS output current of 10.35A! If you're looking for a tube amplifier to drive your old Apogee ribbons, the McIntosh from its 4 ohm or 2 ohm taps will be the perfect choice.
Fig.10 McIntosh MC2000, distortion (%) vs 1kHz burst output power into 8 ohms (black trace), 4 ohms (red), 2 ohms (blue), and 1 ohm (green).
While not remarkable, the MC2000's test-bench results are more than respectable for a modern tube amplifier, and certainly better than most of the breed, particularly regarding output current capability.—Thomas J. Norton