DAC for Sony SCD-C333ES

I am looking for a DAC to replace my Adcom gda-600. My system is as follows:- Sony SCD-C333ES, NAD C340 {soon to be upgraded},Silverline SR 17 monitors. Ilike to listen to classical,blues,light jazz and rock/folk. My new amp is going to be all tube so I am looking for something to complement the sound. What do you recommend considering a budget of up to $700.00.
You might want to have it modified instead of using two boxes andanother interconnect. See tweakaudio.com for an interesting option. Geo.
Check out the Birdland Odeon Lite - retails for 1K but it is up for sale on the Gon for 500-600, Great piece with volume control so no preamp needed if you decide to go that way.
I also recommend the mod. The DAC mentioned is very nice too, but IMHO, the mod on that piece is the best $$$ spent. I've got that unit and spent $500 in mods and there is a WORLD of difference. Get the extras that you'll get for $700 and you'll be WAY pleased. There are also some other mentions of this unit in the forums. Do a search and you'll find several.
Why not get your new tube amp first then see how you like the sound? The amount you are willing to spend on a DAC will probably not give you that much of an improvement-but that same amount spent on mods is a much better upgrade.