Transport for Cambridge DacMagic

Just picked up a Cambridge DacMagic and am using it with an Onkyo DX-7555. Was wondering if there might be an improvement going to a different transport; would appreciate any of your thoughts.
Bob- Probably not what you're looking for, but I feed one (via Optocoupler II Glass Toslink- not USB) with an iMac running AIFF files, and it's really great. I've never used it with a transport, so I can't really address that side.
Please post if you ever use your DACMagic with an Airport Express.

The CA 840c originally would not lock on to the jitter prone output from the AE, though they claim a software 'fix', which should also be on all new production.
A question of budget, of course, but the DACMagic deserves to reach fairly high (imo). If you want to go as far as US1k but not cross that line, a used CEC L2-X (belt driven design) might be tempting. I recall this machine as one of the quietest drives a couple of years ago. Also, you might want to look at cdps with the illustrous Philips CD-Pro2 drive on board.
Could you please describe the improvements in the Onkyo after adding the DacMagic. I have the Onkyo and am very impressed with it. Thanks.
If I am not mistaken, the Onkyo DX-7555 uses the same DAC's(Wolfson WM8740) as the DACMagic with the exception that the Cambridge uses twin WM8740's. It seems on paper that using the DACMagic with the 7555 might have a slight edge. JMO.

J135 - I used the Onkyo by itself for quite awhile and then picked up a Musical Fidelity V-Dac after reading about it in Stereophile. The improvement was pretty apparent; the soundstaging was one thing that really improved; instruments were better separated and easier to pick out. I picked up the Cambridge DacMagic after reading about it in Stereophile and thought it was a tad better than the V-Dac in that it was a little more neutral; the V-dac for the money though is a real nice little unit.
I use my DACMAGIC with a Cambridge Audio 550C CD Player. I bought the DACMAGIC to upgrade an old NAD 541 unit, ¬°but the NAD died suddenly!

After some months using the DacMagic, I think that the differences that the DAC may produce are subtle (using it with a good transport), these are more noticeable with human voices, then a lesser degree with acoustic instruments (like piano, guitar, ...). Then, the differences are much less noticeable, almost imperceptible when compared to electric instruments (like the rock music in general).

What I hear, especifically better with the combination 550C/DACMAGIC is simply more detail, more textures, better definition and enhanced image, and even I fell a more airy sound. In contrast to the 550C alone, I hear a thud sound, as if the speakers were covered by a thin pastic.

I need to clarify something: the Cambridge 550C is an excellent CD player, most people could live with the 550C very happy without an external DAC. I thank that sound of the 550C is better than my old died NAD 541 (if my listening memory don't lie to me, due to the fact that I wast not able to compare both CD players)
So I'm using an xbox 360 with the DacMagic. I have gybytes of music in my computer, mainly lossless formats: flac, ape. The music is transmited wireless to the xbox and then it is sent to the DacMagic by means of an optical cable (by DH Labs).