Cable interfacing issues w/ CD player Need help

Impossible for any 3rd party to conclude, but, IMO the change in CDP ranks as a more likely culprit.

Your comment below suggests this:

" .... Before getting the new player, the Rega Apollo sounded good with the less expensive speaker cable, which I am going to replace with something much better. When I plugged in the new and modded Cambridge Audio CD, using the same speaker cable, the loss of detail in the midrange seemed more evident..."

REGA cdps are fine kit and -- just like their speakers --, they get the midrange "right".

Good luck in your travels

Akg, Thank you for the response. You might be right; however I got to burn-in the player at least another 40 hours before I begin to start to growl at the seller of modded Cambridge Audio 550C player who claimed it would outperform the Rega and much higher priced CD players

However, after today's listening session, using the Morrow Audio MA-3 IC, I was able draw few conclusions: first, the Cambridge Audio 550C player is no slouch, it is much quicker in its transient response than the Rega Apollo, and provides a remarkless sense of quietness between the notes of music especially in the upper mids where every other CD player I have owned or auditioned sounds congested and less trasparent. I am still troubled by the lost of detail and overall richness in tne midrange, but I also noted today that the absense of detail may be just a more balanced, linear, and somewhat recessed midrange, that is, a much flatter frequency response across most of the midrange than the Rega Apollo provided.

On the negative side though, even though the Morror IC interconnect breathed some life back into the sound, it is sometimes bright,and glaring on the highs; these digital artifacts were almost completely absent using the Chord Chameleon IC (which was recommended for the Rega Apollo;) I used the Chord IC early in the evaluation period of the Cambridge Audio player. I am probably going to reconnect the Rega Apollo back into the system tommorrow, and use the Morrow Audio IC, then in a few days, replace it with the Chord IC.....that should give me the answer as to whether the culprit is the Cambridge Audio player,or if the Rega Apollo sounds better with less lost of midrange detail; that may in the end be more attributable to the lower quality of the Audio Art standard SC-5 speaker cable whicg replaced the more expensive and higher quality Acoustic Zen Hologram 2 speaker cable. Regardless, the AA cable despite some merits will be booted out of the system, as soon as I can find a worthy sound equivalent to Hologram 2 which is not bulky and thick, and easy to work with.