But that's just it. They already have the supply, which supplies about 6v. How the "apply" lower voltages isn't by actually lowering the voltage. What they do is turn it on and off really fast. So if it's turned on all the time it's 6v, turned on half the time it's an effective 3v. So they already have all the circuitry needed. It's just a simple programming change to allow the "off" time to exceed 50 percent.
Think of it this way. If I wire an LED up to the output pin of an mcu that outputs say 5v. If I leave then pin on all the time the led lights at maximum brightness. If I cycle it on and off really fast on 75 percent and off 25 percent then it lights at 3/4 brightness. Half the time half the brightness, leave it on only 25 percent of the time and it's only one quarter brightness, keep going extending the off time and it gets dimmer and dimmer. But because it's cycling so fast it appears to be lit constantly even though it's really flashing very quickly, that's how pwm works.
Yep! And in some circles the Fender tube head would win because it's Fender, tube, and old!
And there always the difference in biasing, preamp tubes, and tone circuits and effects loops. I remember reading about an extensive test where musicians and recording engineers were seated in a studio and were told to listen to the same guitar player behind a half wall through three amplifiers and determine whether each were tube or solid state. Almost all missed the mark on the one they determined to be a tube amp.
I play through a hybrid guitar amp these days. It's a Peavey Vypyr Tube 60. The front end is digital, with a 12ax7 preamp followed by a dual 6L6 output stage. I swapped out the 6L6's with a pair of KT88's. Both sound good, but I've convinced myself that the KT88's beat the 6L6's on presence, overall tonal balance, and feel. That may be hogwash, but it makes me happy when I play it!
Oh, and a clean car drives better.
