Unbalanced to balanced adaptor

Jayboard,
The cheapest and BEST QUALITY is to make your own RCA to XLR adapters. The following is from Michael Percy Audio (www.percyaudio.com) You may want to email him to ask if a 75ohm version for digital applications is any different:

By using the Vampire CM1F female panel mount RCA clamped into the strain relief of a Vampire male or female cable mount XLR.
Insulate the RCA with a bit of heat shrink where it is clamped, and use just enough 30ga or 26ga XLO to make soldering possible to the hot and ground of the RCA.
This makes a much nicer adaptor than anything off the shelf... excellent connectors, compact, and minimal amount of wire.
Pin #1 is ground reference
Pin #2 usually non-inverting
Pin #3 usually inverting.
Sometimes the unused Pin #2 or #3 is shorted to ground in an adaptor.
Cost to build each adaptor about $12.00.

I think that with digital there are additional issues - for example, impedance matching (s/pdif = 75 ohms, AES/EBU = 110 ohms) and level (I believe s/pdif is +/- 0.5V, whereas AES/EBU is +/- 5V). I use a Monarchy DIP Classic in part for its s/pdif to AES/EBU conversion; it also improves the sound in my setup. See http://www.monarchyaudio.com/ This isn't a really cheap solution, though, so I suggest you check out this link http://www.rane.com/note149.html which describes the technical issues and points to some sources (which I haven't checked out). You might also try contacting one of the big pro audio sites (e.g., www.sweetwater.com or www.musiciansfriend.com) and see if they offer a cheap solution to this.

I see that I accidentally posted the same link twice, sorry. The actual link with the technical info is this:
http://www.rane.com/note149.html

Thanks for the information. To make the conversion properly does not seem like a simple proposition. I suppose I might also contact the maker of my DAC to see how tolerant it would be of a passive solution. Thanks again.

Cardas makes them. I use them for the same purpose. Find them in the Music Direct catalog. $50 for a pair. I don't find that they make a difference positively or negatively.

Cheers.