Moving from the Esoteric P-05/ D-05 to the K-03

I believe there is a difference between X models purchased new and upgrades of existing units to X status. The upgrades don't get the new DAC, etc.

......some have said that the K-03x with the newer Dac's is almost and not by much- just as good sonically as the discontinued K-01

Just to be clear, 68Pete did a nice job of summarizing (above) the improvements specific to buying a new K-03X vs K-03.

For those looking to upgrade their existing K-03 to "X" it only includes the new USB interface to allow for playback of DSD in native format. The upgrade in the US costs $1,500 which includes shipping back to owner after upgrade is complete.

If you go to the Esoteric USA website there is ample information for both the K-03 upgrade and K-03X. The upgrades are being completed at a facility in CA.

Here is the link for upgrade path:http://www.esoteric-usa.com/USB-upgrade.php

Correct...Esoteric/Onkyo told me the same thing; the X upgrade for the K03 and K01 allows for only the new board and DSD playback in native format. Buying a new K03X or K01X gets you many other improvements beyond the upgraded board. From the Esoteric Japan website;

"Four years after the release of the K-01—the world’s leading all-in-one digital player—the new K-01X debuts as a more compact version of Esoteric’s flagship Grandioso model. Utilizing the same type of highly rigid chassis construction as the Grandioso and a similar four-transformer power supply, it integrates the Grandioso P1’s high-precision VRDS-NEO “VMK-3.5-20S” turntable with two independent monaural DAC units derived from the Grandioso D1 design, each configured with a parallel array of 8 individual converters, which are summed to optimize linearity and minimize noise.
Electronic circuitry has also been further improved with the latest technologies, including a new AK4495S DAC IC, an advanced 35-bit D/A processing algorithm, an HCLD buffer amp, a DSD-compatible USB interface, and a large, low phase noise clock, all ensuring the K-01X achieves the absolute pinnacle of sound quality."

Much more detail on the US Website;

http://www.esoteric-usa.com/Products/audio-players/X-series.php

Well, when I read that and compare it with the info they launched first, it is just another manufacturer which ruins resale prices from former customers because they are not able to do something right. Just another "...ahem, we don't know what to do but we will be first..." Company?
Probably Accuphase is the way to go ..