On The Astell & Kern US site I asked this very question on the SP1000 blog. They may be in denial or they just didn't understand that question properly. I think I did read somewhere though they have a better balance implementation.
Astell&Kern SupportMay 19, 2017
Ray: We never used ribbon cables for the 2.5mm balanced audio output ports on any of our portables.
RayMay 18, 2017
was wondering if the balanced output still use ribbon cables like on the AK380 that I currently own. I think for expensive high end gear like this, the outputs shouldn’t use ribbons on the boards. Thank you in advance for your response.