Tohle mi napsali na foru (clovek z technickeho oddeleni):

The DMP3 isn't designed to accept a line level signal; it amplifies mics and instruments and brings them up to line level. The DMP3 can accept an input signal up to +14.6dBu, and while it may work, I don't think the sound quality will be ideal. I'd think you'd be better off looking into a small line level mixer if you can't get the gain you need from your headphone amp. Rolls makes some small products that may suit your needs.

Tak nevim, jsem uz z toho naprosto zblbly...