Review of TEAC NT-505

You can configure it for fixed volume output.

Yep I run mine fixed volume output to my integrated amp

I'm looking for a DAC that I can roll discrete opamps. Can a person roll opamps in this unit (that is, use socketed opamps to replace the stock ones)? 

Don’t think so, no. 

Please indulge a few questions from a new owner.

1) Do you use the HR Streamer App, or is there something better out there that works well with the NT-505?
2) How do you use the unit to listen to Internet Radio? On the app, the only option appears to be Tune-In Radio, but that doesn't seem to work.  So far, I have just used Bluetooth from my iPad, which doesn't seem very elegant.
3) When I choose the Spotify option, the HR app simply opens my Spotify app.  Is that all there is to that??

Thanks!