Thanks I looked at the Goldenwave... And wow very tempting, very nicely engineered! i want to keep the TEAC PD501as the source it's a wonderful CD player, where I am unhappy is the headphone amp of the AI-501 but also the rather dry in-built DAC. as I bought an Ibasso DX90 last month in Hong Kong I connected this wonderful DAP through RCA cables to my AI501 and wow the dual ES9018 chips beat the TEAC AI-501 DAC hands down.....so basically either I use the ibasso as a temporary DAC and buy a nice headphone amp first such as the A28 or I buy a DA8 Or D200 (it's cheaper...but are they really similar?) or the AK4390 fuelled Goldenwave AND a headphone amp....with this respect I saw a Violectric V200 clone at$300 on taobao, from accurate audio model a200...and as far as google translate goes theV200 and its clone are pretty close in performance.....
Goldenwave has some decent products, and headphone amp is their strong suit, both Amper and GA09 represents the best you can get from China boutique shops at their price range. I think we should support reputable companies such as Yulong, Goldenwave, Audio-Gd, Hifiman for the original effort they invested in develop their own products, and to show my minimum support, I don't want to talk about clones, and will stir away from them even I can't afford something better.
I owned DX50, DX100 and X5, and am familiar with DX90, which is closer to X5 in performance, but below DX100 if you were using the line out of these DAP to feed into a headphone, but still, D200 beats my DX100 hands down, right now I am using these DAP as transport feeding coaxial to my D200 only,
Regarding DA8 vs D200, I think if you are using them as standalone unit, then I'll be hesitate to pay for the different and will stay with D200 instead. However you were to use them as DAC only and will have a headphone amp down the chain, then I certainly will recommend the DA8 instead, In other word, the build-in amplifier of DA8 and D200 is a bottleneck that stop you from full appreciate the advantage of DA8 over D200, Yes, they are different, yes, the DA8 is better, but you won't hear that much if you didn't unleash their full power with a headphone amp.