Schiit Yggdrasil vs. Gungnir

The Gungnir Multibit doesn’t have a "knob". It does have a button you press to select various inputs: usb, coax, etc.

For everyone that owns the Gungnir Multibit, what is the knob for? It doesn't also act as a preamp, right?

I have the current Gungnir Multibit 5 and could not be happier.
Warmer sounding than the Yiggy.

the Gungnir multibit, $1249 has caught a lot of eyes...

I own the Gungnir, and will have upgrades done to it soon.
I also own an Ayre Codex. The Gungnir comes close, and I would expect the Yggy to be very close to the Codex performance.
Both are great machines. 

If I were you, I would get a used Codex for just a shade over $1K. You won't be disappointed.
Bob