Adding a tube DAC to my BLUESOUND VAULT

I recently purchased a used BLUESOUND VAULT ( cd ripper and streamer) and after reading a lot of posts on various sites I may add a Tube DAC in the $500 or less price range to my setup  I have the VAULT hard wired via CAT 6 > RCA out to RCA INPUTS MFA MAGUS A2 tube preamplifier > MEITNER MTR101 MONOBLOCKS > BOZAK URBAN speakers. So, thank all in advance May I have some ideas and suggestions please?
For that low price you will have to buy something made in Ch*na! Which is ok! Look at your smartphone! Guess where that came from!
I think you may need to up your budget to the $1000 or so level and look for a used MHDT Orchid or Audio Mirror Tubadour.  You might also consider a solid state R2R NOS DAC that tend to have a more “analog” type sound, but those too will be tough to find at $500 or less.  Best of luck.