sorry bd you've lost me....

i'm not sure what you're problem is here.

you have a source which creates an analogue signal. this is then converted into the digital domain at a very high sample rate and this is digitally amplified and then re-converted to a louder analogue signal.

where is the upsampling in the amplifier section?

if you are talking about tact style true digital amps (which i'm not and you seem to be) then i can;t comment on how they sound as i've not heard one. this is why i qualified my above statements by stressing the tripath / class - t style of amps.

i like the sound of the bel canto and es labs amps i've heard however my favourite amps by far are the laser biased edge amps.

cheers

julian