Well a mini-review first, compared to the DX90 subjectively, the DX50 is very thick and bassy(think potentially headache inducing) sounding and at the cost of midrange and soundstage. It is also less dynamic sounding however does not have the sabre harshness(duh) that was present in the DX90.
Interfacing it has been frustrating, unlike the DX90, the DX50's screen is simply too sensitive so you keep making wrong selections all the time. Dunno whether its the WM8740 or the implementation but I would think its the latter given the sound I heard from Audio GD's DAC 2(8741) which in comparison sounded large and had good depth.
TL:DR
I think I would stick with my Ipod+amp
Tech part:
Chain: DX50 line out-> copper foil shielded 3.5mm to RCA ->EMU0404(linear PSU) via ASIO
*Note: Measurements were taken with "0dbFS" at 0dbV
RMAA(DX50.zip) measurement is for headphone out.
For the DX50, it actually has a lot less jitter than its bigger sibling the DX90, aside from that I reckon what was bogging down the performance was the intermodulation distortion performance of the DX50, it seems pretty marginal compared to the reference EMU0404's measurements and the DX90 which has better IMD performance and thus probably sounding cleaner and less muddy. Did not include resolution measurements as the levels used do not make use of the full noise floor to get anything useful. Also not included is the 1khz square waves but the filter used on the LO at least seems to be the normal symmetrical linear phase type.
The amp's performance is okay and does pretty well loaded with my Klipsch X10(a mistake of youth) and meets the specs posted on Ibasso's site. Its also interesting how the amp changes the character of the DAP's DAC. Take note that measurement is taken at -10dbV.
