To the more senior level audio experts there i have a question regarding how headphone amplifiers handle the signal depending on input ANALOG IN or DIGITAL IN..
ths question does not target a DAP in particular nor an AMP brand in particular, lets asumme the drawing as a black box model grossly simplified
so as i understand amps when fed can behave in three modes as i have come to understand, some amps may or not have a DSP processor bult-in so dashed lines are mean as optional component int he AMP architecture.
So here is my understanding on how different inputs work for an generic amp
A) The player detects a LOD (f.e. Fiio L5 or any lod for f.e an ipod or sony player), gets the song from the memory, the song gets converted to ANALOG via the Player's DAC, bypasses the player's amplifier circuit, when entering the portable AMP via AUX-IN it only gets amplified by the amp's amplification circuit.
B) Same as "A)" but this time the portable amp, re-encodes the analog signal from the LOD via the ADC back to DIGITAL, can or may not apply DSP processing, Converst again to ANALOG via the portable amp DAC, amplifies the signal to headphones.
C) the player grabs a song, bypasses both DAC and amp, in the Portable amplifier DIGITAL IN, the signal may or not be applied DSP processing, the signal then passes to the headphone amp DAC and gets amplified by the amplification circuit.
Tht is how i understand how amps work and many brands only offer those with analog input meaning potentially doing DAC-->ADC-->DAC-->Phones
That's why i ask this and why i consider one that has a digital IN to avoid double DAC'ing