How do Digital Amps Mfrs. compare in sound?

Of course I empathize with you Coffeey. . . it is really sad how things have the habit of being. . . and even more of changing and evolving. . . in spite of our better doubts, nostalgia for the safety of olden days, or tradition abiding skepticism. . . It's like we don't matter any longer to this mad mad World. . . 'Fore long we'll have to get out of the house and listen by wesselves to what's good with this hobby. . . because even the old tried and true "I truly believe it therefore it's true" does not sound so hot any longer among far too many young whippersnappers. . . there's no more Religion no more, I tell ya.

My very last refuge is in the stern wisdom of one of the greatest sages of our Age:

"Just don't fall into the category of those whose minds, like concrete, are thoroughly mixed up and permanently set"
RODMAN99999

Regards, G.

Guidocorona, you're a piece of work. You hear angels don't you? I know the "Consciously Guided" when I hear it. I'm going to start calling you "YODA of HIFI." ;)

hmmm, me thinks last time I heard 'em voices I was 16. . . right in the middle of the Sturm und Drang of adolescence. . . now I'm only a crotchety old prankster foolin' 'round with words and audio components.

Hi Coffeey, small design improvements can make large changes in sound quality in any design. Class D amps have always been good, maybe not great but good. UCD in the last year and a half has redesigned their boards and have chosen some better components. Class D amps use allot of surface mount parts and that is the reason most companies buy modules from B&O (ICE) or Hypex (UCD) and then design and build their own power supply. Now that class D production has picked up, many surface mount component manufacturers are willing to set aside the better parts for these designs. Most, if not all of the sound differences between tube and solid state amps are the parts and power supply. The same applies to Class D. Circuit topology for tube and solid state haven't changed much in decades. So how is it possible for a manufacturer of these amps to make their product sound better then last years or even 10 years ago? Parts, board layout, isolation and power supply.

Excellent points Stereo. I would like to add that at least 2 manufacturers (Bel Canto and JRDG) have started to add pre power supply current rectification in some models. This means that the power supply is essentially fed DC from a current reservoir of capacitors. The idea is the DC current is expected to:

1. largely eliminate 2 way AC line noise in and out of the amp.
2. Keep internal capacitors more optimally charged.
3. Be able to draw power for large transient from the DC reservoire regardless of the current state of AC 50/60 Hz phase.
4. Increase overall power conversion efficiency.

Some of these amps do sound amazingly musical to my ears. . . if and when more devices adopt various form of rectification prior to power supply, we may eventually be able to determine if there truly exists a correlation between input current rectification and sound quality.