Bryston 9B-THX five-channel power amplifier Measurements part 2
Fig.7 Bryston 9B-THX, distortion (%) vs continuous output power into (from bottom to top at 2kHz) 8 ohms and 2 ohms.
To test the 9B's ultimate power, I used the Miller Audio Research Amplifier Profiler, which drives one channel of the amplifier under test with a low-duty-cycle 1kHz toneburst (10 cycles on, 400 cycles off). This more closely approximates how the amplifier will behave with a music signal. Fig.8 reveals that, under these dynamic conditions, 227W was available for 1% THD (horizontal magenta line) into 8 ohms (black trace), 410W into 4 ohms (red), 680.5W into 2 ohms (blue), and 967W into 1 ohm (green). The latter is equivalent to a current delivery of 31.1A!
Fig.8 Bryston 9B-THX, distortion (%) vs 1kHz burst output power into 8 ohms (black trace), 4 ohms (red), 2 ohms (blue), and 1 ohm (green).
This excellent set of measurements indicates excellent, reliable engineering.—John Atkinson