PHONE - Pixel 6 Pro
OS - Android 13 beta 3.2
DAC - TempoTec Sonata HD PRO (Android...
APP - USB Audio Player Pro version 6.0.7.6
IEMs - Shure SE846-CL Professional Sound...
I don't understand why there's a blue dot vs the green dot, why the USB DAC sample rate is different from the FLAC file one, or what the bit rates mean and why there are two.
Forgive the newb lol
Wrong sub, read the rules (specifcally rule 7), but I'll answer anyway.
There is no combo DAC/amp under $300 that includes tubes that are actually used for anything. The ones like that you're seeing are "hybrid tube" amps, which essentially means they are solid-state, op-amp-based amps that have tubes meaninglessly added to the signal path and providing no gain. They are there 99% as a decoration, and usually the quality of the solid state part that is actually providing the amplification is mediocre.
Due to current sales, it is possible to get a separate DAC plus a real, actual tube amp at $300 though. Just not built into the same box. Buy these two products:
https://www.amazon.com/TempoTec-Sonata-HD-PRO-Android/dp/B084YX4MZD
https://drop.com/buy/dark-voice-366se
And then connect them with a 3.5mm to dual RCA cable. The 6XX should be very happy with this setup.