Muralman -
"What is the advantage of introducing a digital power supply into an analog amp?"
First of all it's not digital supply - it is as analog as class D. In fact IT IS class D (class D was invented when designers of SMPS were demonstrating that it has such fast response that it can even play music.
Advantages are few: It is line and load regulated (while linear power supply is not) and quieter (50kHz is much easier to filter out than 120Hz). Just take as an example Jeff Rowland's Capri linestage - it uses SMPS instead of linear power supply (that would be small and inexpensive) and Jeff Rowland is not a "noisy" guy (he used batteries in preamps before). Don't be fooled by size of SMPS because 2" in diameter torroidal transformer can pass as much power at 50kHz as huge 10" torroidal transformer at 60Hz.
You made already one step accepting class D. Make another one - it is the same thing.
"What is the advantage of introducing a digital power supply into an analog amp?"
First of all it's not digital supply - it is as analog as class D. In fact IT IS class D (class D was invented when designers of SMPS were demonstrating that it has such fast response that it can even play music.
Advantages are few: It is line and load regulated (while linear power supply is not) and quieter (50kHz is much easier to filter out than 120Hz). Just take as an example Jeff Rowland's Capri linestage - it uses SMPS instead of linear power supply (that would be small and inexpensive) and Jeff Rowland is not a "noisy" guy (he used batteries in preamps before). Don't be fooled by size of SMPS because 2" in diameter torroidal transformer can pass as much power at 50kHz as huge 10" torroidal transformer at 60Hz.
You made already one step accepting class D. Make another one - it is the same thing.