Your experience with an inexpensive DAC?

I have a main system and a bedroom system for late night headphone listening.  I have not upgraded my digital end of the system, but do not want to spend/do too much at this point.  So my question, what have my friends here at AudiogoN had  success with in a DAC?

I have an Oppo and two of the better high-end, but older Pioneer Elite players.  So I am thinking that a good sounding DAC may be of use to me.  

I do have a prejudice I may have to set aside, as in me liking components with tubes or transistors but not op-amps/I.C. chips.  Perhaps I am a dinosaur?

For what it's worth (great song) I listen mainly to classic Jazz and lean towards acoustic instruments rather than electric and I listen to many female vocals, Ella, Dinah Washington, Diana Krall, Carmen, and even though he had a bit of a messy life and a limited vocal and instrument range, I do listen to much of early Chet Baker and Paul Desmond, Miles, Earl Garner, et.al. 

Thanks for your thoughts/experience, Jim