As usual, sorry for my English. If you find mistakes or nonsenses in my post, feel free to send me a "patch" on mp, I'll correct my post.
Based on the informations provided by James, eg Android and big touchscreen (damn' I was going to ask to get rid of those craps), let's go to (the beach?) :
For the size, ergonomy and the OS
- Reduce the size to match the Fiio X5's one for the lenght and width ;
- 20mm for the height seems big enough ;
- Don't make the touchscreen too big, 4" seems the maxmim limit we can handle for this size (3,5" would be perfect) ;
- You want Android, OK. Make it rootable so we can optmize quickly and easly your DAP ;
- You want to make your app', OK. Bring something new and fresh to your customers. We don't want to see another music app who don't change anything for us. Look on what others apps are weak and make it happen ; (One nice thing I want to see : The possibilty to switch folder not only files)
- Android means you have to handle Wi-Fi. It will take down the battery and we can say bye bye to a decent battery life. Handle that nicely ;
- Android means you gonna maybe have to handle Bluetooth too. Don't take a weak bluetooth module, take something recent ;
- Don't try to customize Android to make it prettier or anything, the stock version is good and your gonna lose your time to tweak it ;
- Give us physical buttons. Take inspiration from Sony and the F-886 or the ZX-1 ;
- Android means that you can give us Audio OTG throught the micro-USB port. Make it happen with the lib-audio librairy ;
- LO, HO and Coax Out would be nice as in others Fiio DAP ; I don't see balanced output like a killer feature but why not.
- A battery life of 10h - 12h with 16/44.1 files.
- No interne memory for the users and everything on an SD cart, feels good for me.
For the DAC parts
- Whatever you choose, don't make dual dac. Take a good chip with a low power consumption or lower than most of dual dac, your big touchscreen will eat the battery life don't add unnecessery take down of it. ESS, TI, CS, Wolfson, take what you good with. You're making a DAP not a nuclear plant so be clever and your choice some chips consume more power that others.
That part seems short but all I expect from Fiio is to stay Fiio. Don't run after the hype, don't make insane choices. My point of view is : If you would make a DAP for sound-only purist, you'll not choose Android instead of a home firmware. If Fiio choose Android, it is to anwser to a larger panel of users who look for connectivity, a half-PMP more than a DAP. That's your choice but Fiio have to be consistent with it (Do not make a DX-100 bis, please).
For the Amp parts
- Fiio always makes powerfull amp. Go that way. If your amp can reach the SQ of an O2 to my ears, it would be perfect for me. For the moment, I never met a DAP with an amp who could reach the O2 SQ. I'm biaised mostly because I liked a lot that amp but I can dream a little bit here :) ;
- Go to a colorless signature with good dynamic that all I want ;
- Keep the output impedance less than 1 Ohm ;
- No hiss, noise. Black background ;
All my demands are based on the fact that making an Android device is a trade-off and I don't expect to see *my* perfect DAP on this basis. My perfect DAP would look like the Fiio X3, an ESS9018-K2M alone for the DAC chip and an O2-like for the amp. I'm not a touchscreen/android guy when it comes to DAP. Just to explain the biais in my demands.