Mode A (PMD100) vs. Mode B (DF1704)
Mode B:
After letting the new Mode B burn-in for a little more than 10 hours while I was at work I gave it a second listen.
Well, after being initially impressed by the high frequency extension, I realized that a lot went missing since moving from mode A.
The balance of sound is very close to the EMU 0404 usb, while having a bigger soundstage, better bass and definition.
I know, that the digital module still needs a lot of burn-in, but after about an hour of listening, I got tired/bored with the "hi-fi"/"monitor" sound and swapped again mode B
Mode A:
Well back again to mode A (pmd-100) and I amazed again about how good it is sounding.
The sound is natural and well balanced throughout the sound spectrum. The soundstage is also very natural.
Mode A also conveys better the emotions of the music. There is soul to the music. It is what you would expect from a tubed output but without the coloration of the sound. The sound is delicate and beautiful.
The sound is clearly what you would expect from a well tought high-end product that doesn't try to impress you in the first few seconds, but rather tries to convey the emotions behind the music.
It is strange that I had to listen to the df1704 in order to understand how good is the pmd100 module.
Conclusion:
Having both modes is like having 2 different DACs.
I haven't realized until now how much the digital is important for the sound. In fact, I heard bigger differences between the df1704 and PMD100 than I remember haring when I used to swap opamps in the Zero dac and audio-gd DAC-100.
I am sure there are some people that might prefer in their systems the mode B (df1704) but I think that most will chose the mode B (pmd100) which is overall better as digital filter, as recommended by Kingwa.
There is only one drawback to the pmd100, it doesn't accept 24/96 files but I prefer listening to 16/44 through the pmd100 rather than 24/96 on the DF1704.