Oscarrr, I have enjoyed this thread as I have many friends considering the same. You have garnished a great deal of input, most of which I agree.
1)Driving a DAC with the AE via SPDIF would be an improvement.
2)A computer playing WAV or AIFF quality files into a DAC would be additional improvement.
3)There are many DACs available (new or used) that would satisfy your needs.
As a further thought:
There are a number of DACs that came into the marketplace ~5-7 years ago that were and still are very good DACs. Their weak link has been the USB input if indeed one is provided. Given that the AE outputs SPDIF you can avoid the USB input on one of these older DACs. They often sell used for 30-50% of original retail. The Cambridge Dacmagic might be a place to start. Has 2 coaxial SPDIF inputs, which many do not, and this can come in handy for other sources. Should be able to get a used one for ~$250. The Musical Fidelity V-DAC could be bought used for less than $180. PS DL III for ~$350 - $400. You can keep a used DAC around for a year or two, resale it at a reasonable % of your cost, upgrading later after exploring the marketplace.
