The better the amp´s transformer (lower impendance), the lower the difference between peak and continuous power, so for me a quality issue.
Some unsolicited background
The reason why I looked into the whole issue of max. amp. power was the desire to define a point on the pre amp volume pot scale (at 2 o´clock position in this case, leaving 12dB more preamp gain), where serious distortion will occur.
For that purpose I created a test signal with L/R alternating 400Hz bursts (20% duty cycle and L, R shifted ).
That leaves the thermal load on the bass/mid speakers at a decent level and has only little high frequency content to protect the tweeters. The nice thing about this signal is the easily audible detection of clipping.
Compared to a continuous sine wave on both channels there was little difference in vol. pot position, when clipping occured, which speaks for the amp´s (PSU) quality in my opinion.
Neglecting some 1dB DAC-oversampling-output-level overshoot from already clipped music tracks or the 5-10% variation in mains voltage, I can be relatively sure not to overdrive the system and maintain highest possible fidelity, when listening loud (e. g. for just a few old Yello tracks)...or very high dynamic performances (e. g. ECM´s Il Pergolese).
DC cables...between $30 and $50 ...
