Wanting to upgrade my newly purchased Mjolnir 2 tubes from stock to these. Been looking online, but have only found them on eBay. Are these sellers to be trusted? If anyone has links to where to buy these authentic tubes, it would be appreciated.

Recently purchased Schitt Mjolnir 2 (should be shipped soon) with Modi multibit for my HD800S. Looking for tube replacements to deliver a warm, smooth sound with slammy bass, but take the edge off the treble. I mostly listen to EDM (John digweed, deadmau5, rezz), indie rock/alternative (alt-J...

TL;DR: Is Yamaha MG10XU mixer a good enough DAC, or should I upgrade? (With Schitt magni 3 AMP) I recently order some HD800s' and should receive them Monday. My setup will consist of audio from my computer > Yamaha MG10XU > Schitt Magni 3 > HD800s. I also have a Shure SM7B mic going to the...