Sorry, the suggestion is KA3. Go ahead with the Tempotec but I'd honestly recommend the KA3 over it since I bought an xDuoo amp once I started EQ-ing since the Tempotec wasn't pushing it for me. Honestly, I could have saved money by going with the Apple Dongle + xDuoo amp combo and achieved the same results. 2 years ago, the KA3 wasn't an option else I'd have definitely got that for a portable but somewhat powerful USB DAC/AMP.
I'm not dunking or even commenting on the Astros/PC38X since I don't know enough about them and can only recommend/talk about products I have experience with or have read enough about. Honestly, if you want to get one of those then go ahead; no chance you will be disappointed if the PKCell man himself likes them. I took a chance on the HiFiMan 2yrs ago and couldn't be happier; who knows what I'd be saying if I had gotten the ATH M50x instead