The first one is absolutely not safe - it looks like they're trying to turn an unbalanced 3.5 into a balanced 2.5. You'll fry the ES100 and any other balanced piece of equipment you plug it into. The second link looks like the same issue since it doesn't specifically say "balanced". I wouldn't chance it. You can't go from an unbalanced headphone cable to balanced (2.5 mm in the case of the ES100) with an adapter. It doesn't work that way. You have to get a cable that's wired that way, they are fairly easy to find and come in many different plug types (2-pin, MMCX). You can get adapters to use that with unbalanced 3.5mm plugs on DAPs that are not balanced, I do that all the time. In fact, one of my adapters looks like that right angle plug.