DAC recommendation for an entry level system


I would like to add an apple TV a Logitech Squeezebox Touch and a Dune HD Prime 3.0 blu-ray player to my system which consist of NAD C375BEE Integrated amp, Rega P3 24 and Revel Concerta F12 speakers and would like to know if anyone can recommend a DAC. I have my music collection ripped to FLAC and Apple Lossless on my server. I can go up to $600 and I'm willing to buy used. TIA
samaritano69
I am using an older version of this, it sounds surprisingly good. The only thing well known that I've compared it to is a Wadia 121.... My Dac was richer, more organic with similar detail and sound stage.... But, what I have has an inferior USB decoder and I am using an Audio GD USB to Spdif. This is a very good value.

http://www.ebay.com/itm/Valab-ES9018-Sabre-Asynchronous-32bit-192K-USB-DAC-with-XLR-Balanced-Output-/251299941940?pt=US_CD_Players_Recorders&hash=item3a82a4ce34
Thanks, Tony. I noticed that Spotify sounds better when I run it from my ipod through a Pure (transport) than if I run it off my Squeezebox. Same coax cable, etc. Have no idea why...
Mjmch2003,

I don't doubt that at all. The Squeezebox is great as a sum of its parts, but it isn't the greatest at actually playing music. I've been tweaking my Squeezebox Touch for a while now and have been able to attain a higher degree of detail, wider sound stage and better bass.

A lot of the improvement in the Touch's sound quality has come from modifications that disable the wireless and the screen. If you have a Touch and are interested, look into Soundcheck's Squeezebox Toolbox (TT 3.0) and a third party app called "Enhanced Digital Out." Each has its own effect on the character of the music coming out of the Touch.
Micromega MyDAC: Asynchronous USB/Toslink/Coax 24-bit/192 Khz DAC for just $369. Check out the reviews linked from the "Reviews" tab. TAS was ecstatic about this unit.