Early this year I finally got a really nice guitar amp again (after selling my wonderful old 1967 Fender Deluxe Reverb a couple of years ago). It’s a clone of a 60’s blackface Fender Vibrolux Reverb, crafted by King Amplification of Santa Clara. They didn’t just copy the circuit with the nominally-specified component values, they measured the actual values from a particularly sterling, great-sounding, actual 60's Vibrolux and used that as a baseline. (Values of those cheap resistors and caps and such typically had something like a 15% variation in actual measured value, plus they would change over time. So some of those amps sounded particularly sweet sort of by accident.) In building the clone they used better-grade components that have much tighter tolerances and won’t change much over time, so the amp came to life sounding killer and should stay that way.