You get the best quality price solution with a memory source like:

Any usb device or wireless connection using

Teac Wap5000 costing 250$
Harmony Design DAC9 with optical input with Volume feature 700 euro
TPf2l 60wx2 final amplifier costing 150 euro

You will be surprised by the true hi-end quality sound also with MP3 files.

The last one here above on the right is the pre9 harmony design preamplifier you have to add to use external analog imput