Unfortunately, I won't be able to get the Asus Xonar Essence STX, although I can get the Asus Xonar Phoebus Solo used for €50. Would that be a decent alternative?

Thank you very much for the advice! I'll get one of the Asus cards and depending on which one I can get my hands on, will use either the card or the Sansui to drive the HD 650's. Whichever sounds best. Thanks again.

I've found a Micromega Minium AMP + CD for €175 at a local Hi-Fi store. Would this be a good deal and would it work properly with the HD 650's.   Also, in my original post I mentioned BMWi speakers, I meant B&Wi. (Oops)

Thanks for your reply. I see the O2's a lot around here, though the combo is unfortunately above my budget. I will look around for a used combo, but it's hard to find for a decent price + shipping & tax here.

Thank you for your advice. I can get a used Asus Xonar D1 for about €30. I also looked for other Asus soundcards and can probably get a used Xonar Essence STX for about €70. Do you think that card would be worth the extra money? I assume that I would plug the HD 650's into the STX directly...

I've just bought an HD 650 and am looking for an amp or dac/amp to go with it. The HD 650 will be mainly used with my desktop.  I have an old (Sansui A-E750) amp that is hooked up to two B&Wi speakers which I inherited from my parents.  The old amp is hooked up to my desktops on-board audio. I...