You send a 48 kHz file and the display of the DAC says it receives a 48 kHz file, not to be mistaken for "output".
Of course the output will never be 48 kHz because the output of a DAC is always analog.
Just an example, my veteran Benchmark DAC 1 has a AKM DAC and internally resamples every thing to 126 kHz.
According to the developers this simply gives the best results.
Please observe that "bit-perfect" is in general not about DAC's but about avoiding the operating system to degrade the sound.
NOS are often based on a Philips TDAxxxx design from the 80's.
Indeed the first generation was NOS and imho sounded horrible.
Well, I am totally unaware of how things work.
The input shows indeed what I feed it.
But the DAC also has a digital output.
If I hook that to another DAC, the input of the second DAC shows the same as the input as the first DAC.
But maybe that digital ouput is just a "passthrough" ?
Anyways, as I said, I like what I hear coming out of my Amp fed by a OS DAC.
So I think I can live with it... even though I now have a little more knowledge and won't naively think the sound comes out "unaltered"...