I also like using recorders for DAPs. My Tascam DR-07mkII is a great digital audio player. It is easy to transfer files via USB. It has a great D/A converter, rechargeable batteries last a long time; what's not to like.

What headphones/earphones are you using for your tests regarding sound quality? The D100 provides 50 mW of power at 16 Ω according to their specifications.

May I ask for some more detailed impressions vs. other daps you've either used or own still? Thanks. I'm currently trying to decide on this or the MSAK100, which seems to be in some ways better than the AK240 in terms of depth of soundstage and more quantity and quality of bass.

Thanks again