"After all, musical peaks are voltage driven, not current driven."
In the world I live in, musical peaks being reproduced by a power amp produce power, not merely voltage. Voltage in a speaker cannot exist without current and this is inviably defined by Ohm's Law and the Power formula (Power=Voltage X Current).
So- a musical peak delivered by a power amp has a voltage component- *and* a current component. Since the peak represents a peak in power as well as voltage, current must therefore be peaked also.
The idea that the peak is voltage driven comes from the Voltage paradigm I've mentioned in a few threads here. What I've not mentioned is that paradigm is actually that- a paradigm, and not one based on reality. It is in fact an artifact of the 50s and 60s when transistors were making their way into audio. A central precept of the Voltage paradigm is the use of negative feedback (ostensibly to reduce THD); such use is in violation of the rules of human hearing which we all subscribe to by default.
The violation, for those curious, is the addition of odd-ordered harmonic content that negative feedback brings.
A curious artifact of the Voltage paradigm is that nothing but voltage matters in the response of an amplifier. Another is that 'voltage source' amplifiers are also defined as 'high current'. Yet another is the idea that speakers are 'voltage driven'. English speaking people will note some contradictions.
The Power paradigm aims to correct these oddities. First, *all* speakers are power driven. All power amplifiers produce power. 'High current' does not exist for musical reproduction without the generation of power, and the same is true of voltage. In this way, the power formula and Ohm's Law are satisfied within the conversation of power amplifiers and speakers and at the same time the meanings of English words are also satisfied.
Within the conversation of this thread, the issues relating to why tubes are somehow able to produce more *usable* power when their total power is less than that of transistors is easily revealed by the Power paradigm, which has it roots based on the rules of human hearing, rather than a thought model conceived to sell transistor amplifiers in particular.
The answer is that tubes generate power in a way that satisfies more of the rules of human hearing than transistors do. For example, SETs get their dynamic punch out of their harmonic generation: odd ordered harmonics are masked by even orders, so while the amp sounds lush, the odd orders are triggering the human ear to hear dynamics on peaks. It is an illusion.
Other, lower distortion tube amplifiers still manifest a greater percentage of *usable* (musical) power by the simple use of components that are inherently more linear than transistors, and usually with less stages (meaning less places for things to get messed up), objectionable distortions are minimal, resulting in little or no feedback being required for the amp to do its job. Thus the human ear is not *as* offended, and the bottom line is more of the amplifier's power generated can be used for meaningful musical reproduction.
In the Power Paradigm the rules of human hearing are not ignored so an amplifier can measure well and sound good too because the pertinent specifications that are important are the ones that get measured.
In the Voltage paradigm, as Pauly points out:
"I have never found any correlation between measured numbers like THD and what the amp sounds like to my ears. In fact have heard amp with excellent THD number that are useful only as doorstops."
-that there is no correlation between specs and sound. There is a huge disconnect here! The Voltage Paradigm seems to equate to the Emperer's new Clothes. After nearly 50 years- *that* would seem to be a little old :)