Fwiw I have both a jotunheim and Vali 2. I noticed no difference at all switching back and forth when I level matched using a multimeter on my hd800. Haven't tried tube rolling, just the stock Vali 2 tube. I used an a/b switch and really tried to notice differences by playing the same passages of songs back to back. I got nothing, they sounded the same. Either amp has plenty of power. Just get the one you want, unless you plan on tube rolling.