Conrad-Johnson Premier Eleven power amplifier Measurements part 3
Fig.8 Conrad-Johnson Premier Eleven, HF intermodulation spectrum, DC-22kHz, 19+20kHz at 22.6W into 8 ohms (linear frequency scale).
Fig.9 Conrad-Johnson Premier Eleven, distortion (%) vs output power into (from bottom to top at 10W): 4 ohms, 8 ohms, and 2 ohms.
The Premier Eleven's test-bench results are good for a medium-power tube amplifier. The only matter of any concern is the slightly high low-frequency THD, but I wouldn't be put off by this if the amplifier auditioned positively—as it did!—Thomas J. Norton