Allow me to back up Ralph's point on impedance from personal experience.
For years I owned a pair of highly regarded speakers which the manufacturer rated at 90 dB efficient. I auditioned many amps with those, both tube and SS. One day a friend brought over a tube amp he scratch built which he estimated would be rated about 30-40 wpc. Since he'd had good results on a few other speakers we were both surprised when it simply fell on it's face attempting to drive mine.
After some discussion he suggested two reasons for the failed performance. First off, my speakers were designed for time/phase integrity so had first-order crossovers. The crossover board could be viewed by removing a cover on the back of the speakers and that revealed a very complex (number of components) board. My friend joked that all that was needed was the addition of a transformer and they could power themselves.
The second reason was the impedance plot. It dipped slightly below 3 ohms at two frequencies. I don't remember exactly now but they were around 50 Hz and at 10K Hz.
His amp worked with other 90 dB speakers but failed with mine since they could not adequately drive that load.
In fact I owned a pair of Ralph's MA-1s for nearly a year. With non-complex music they sounded wonderful. But with complex music (full orchestra symphonies, big band jazz, etc.) at moderately loud levels, even their 100 watts was not adequate. That was the fault of the mis-match, not Ralph's amps.
For years I owned a pair of highly regarded speakers which the manufacturer rated at 90 dB efficient. I auditioned many amps with those, both tube and SS. One day a friend brought over a tube amp he scratch built which he estimated would be rated about 30-40 wpc. Since he'd had good results on a few other speakers we were both surprised when it simply fell on it's face attempting to drive mine.
After some discussion he suggested two reasons for the failed performance. First off, my speakers were designed for time/phase integrity so had first-order crossovers. The crossover board could be viewed by removing a cover on the back of the speakers and that revealed a very complex (number of components) board. My friend joked that all that was needed was the addition of a transformer and they could power themselves.
The second reason was the impedance plot. It dipped slightly below 3 ohms at two frequencies. I don't remember exactly now but they were around 50 Hz and at 10K Hz.
His amp worked with other 90 dB speakers but failed with mine since they could not adequately drive that load.
In fact I owned a pair of Ralph's MA-1s for nearly a year. With non-complex music they sounded wonderful. But with complex music (full orchestra symphonies, big band jazz, etc.) at moderately loud levels, even their 100 watts was not adequate. That was the fault of the mis-match, not Ralph's amps.
