Kickstarter or sth the like is a good idea in the furture.Let's see how the market respond to the A4.Personally, I like the A4 a lot. A killer for pop. The smooth texture of A3 remains with extra details, more precise positioning, and larger soundstage. It's much better than the prototype.
I think you can contact the retailer. When I buy DIY IEMs, I don't expect there is warranty.Though if you buy the IEM directly from LZ through Taobao, he does offer warranty. HOWEVER, it is kind of impossible to ship the IEM back to China because of the custom...
LZ refers to Lao Zhung, a guy.
"Zhung" is his family name, and "Lao" means old, or looking old.
It looks like LZ can't make any more A2, otherwise he wouldn't make a different A2S.
A wild guess is that he couldn't get the drivers used in A2?
Listening to iPhone 7 through it's given adapter, the sound quality is hopelessly poor.
I've also found that it won't support APT-X. It looks like I should give up the thought of listening music using the iPhone.