(rf) quiet audio amps
 

what is the quitest. tube?

these tripath-amp chips from cirrus are just insane. unless its
something else inside sonicimpact's thing.

trashing the switching power supply helps somewhat

ive seen '1 bit' mentioned in relation to their design. which implies
the DSD kind of thing where you run the clock at some multiple of
2.822 mhz or so. in any case a good portion of listenable spectrum is
completely shot, only somewhat mitigated by shielding