Yeah, 6922EH is great tube for electronic music imho. Makes it more "airy". Still one of my favs for electronic but it`s my personal preference. 3 other great tubes for electronic atmospheric music I recommend: JAN Sylvania 6922 (littlebit better mids & tighter bass than 6922EH but somewhat tinier soundstage) , Tungsram PCC88 (tighter & punchier bass than 6922EH), Mazda PCC189 (lacks littlebit @ mids) & Ultron PCC189 white label (not so airy soundstage as 6922EH but great transparent sound).
Btw, it`s kinda weird that your Amperex has same highs that 6922EH does. Amperex orange should be noticeably warmer @ highs. Not sure but maybe those cans won`t react so well to tube changing and aren`t so good match with Aune T1. One more thing - is your audio source set up correctly? ASIO, WASAPI or KSP? And just in case - are you using USB audio source? Because tube buffer is being used ONLY when USB input is chosen.
I definitely prefer the Amperex over the 6922, it does sound warmer in general, I just didn't notice that much difference in the highs. It felt more like because the 6922 is arier it made the highs sound brighter while the Amperex evened things up. Sorry I'm new to this though, so my ears probably aren't 'trained' Could also likely be the MP3s I have or the music—I will do more listening!
Hmmm I'm on the Mac and in sound preference the T1 is selected. The switch on the T1 is also switched to USB, not Line.