classA push-pull has an efficiency of 25- 50%max, so at 40watts output, dc input must be 80 watts, that is too optimistic for a 6L6gc unless you are willing to be replacing output tubes every now and then....
(classAB has a classA reqion, ussualy the first few watts, now as sound level demands go up, they leave classA region and transitions to classB, that is why they are called classAB......classB is not so bad as some would like us to believe, David Berning's amps are like that.....)
with 30 watts plate rating, i can not see how it is possible, classA operates the tubes at maximum plate dissipation all the time...
classAB operates tubes in the 60 to 70% range so that tubes last longer...
but why worry about wattage? i stopped counting watts a long time ago.....sound quality is the most important.....
a 20 watter amp can sound the same as a 40 watter...amplifier wattage was invented by the marketing boys to justify the higher costs, the higher the wattage, the more expensive it becomes.....it is never a yardstick for quality....
most of the things we hear are borne out of our prefferences and biases which may or not jibe with reality....
reality is, if you want to know the power of your amp, the way to do it is by using dummy loads, a scope and a function generator, ac can then be measured at the onset of clipping....
consumers are really at the mercy of vendors, even if they say that amp is 40 watts, how are you going to know for sure?
so for consumers i suggest that the focus should be on the sound quality, how your amp drives your speakers is what really matters in the end...
