Unbalanced to balanced adaptor

I'd like to take advantage of the AES/EBU digital input DAC -- just for the additional input. It's a balanced input, but none of my sources is balanced, and the unbalanced inputs of my DAC are already used. Are there cable adaptors that will allow me to take the S/PDIF (RCA coax) output of a transport into the AES/EBU (XLR balanced) input of my DAC?
I should keep an eye on this post
Using a adapter to go XLR to RCA .
Some suggestions are showing up there.

However, does the fact that I'm talking about a digital connection make a difference in adaptors I should consider?
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:
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.

Did you ever resolve this, Jayboard? My impression is that it's not like converting unblanced to balanced interconnects because you are taking one standard (S/PDIF, here implemented as coax but it can also be done as Toslink) and converting it to a different standard (AES/EBU). But maybe that doesn't matter.
My question had to do with my DAC, but I came across this helpful info in an FAQ for the DEQ2496 at Behringer.com.

>>SPDIF (consumer format, unbalanced, normally characterised by the RCA co-axial connectors) is digitally simpler, whose basic information id unit utilises 4 bytes, (each byte being 8-bit).

AES/EBU (professional format, balanced, normally characterised by the XLR-type connectors) is digitally more complex, the basic information id unit being a differently structured 6 byte format (again each byte has 8 bit). The differences in impedance are not critical, but the fact the AES/EBU is both digitally more complicated and generally of a higher operating voltage means that AES/EBU signals will not be recognised by SPDIF (consumer) equipment.

It is however possible, although not guaranteed, that an SPDIF signal may be recognised by AES/EBU (professional) equipment. You can always test this on your own equipment by constructing an adapter cable (RCA - XLR). Because of the lower operating voltage of the SPDIF signal, this will not distort the signal or damage your equipment. (good reason for not trying it the other way around!) <<
i tried a bat balanced connector and a rca digital cable and it degraded the sound....

the whole idea behind a balanced signal is the dual differentail with cancelling......