What is the affect of cd player?

There is no "most important" in an audio chain. Think of yourself as looking at a garden(your recording of musicians in the original venue), through a number of glass panes(source to ears/your electronics and room). Does it matter which panes of glass are dirty or off color, with regards to what you see? Some components have a harder job to perform than others. I've always considered converting a series of electrical impulses into sound waves/music(accurately/believably)and interfacing that with the average listening room, as the most difficult to accomplish. But, that's just my opinion. The player you own is highly regarded/sounds damn good, and yes- You'd have jump a couple performance levels to improve on it(at least get into a tubed output player). Again- my opinion/experience. The improvements in the upper tiers of what's available in players are way more than subtle, affecting sound staging(width and depth), image size and height, instrumental timbre, detail without grain/stridency, frequency extension in both directions.... well- basically everything important to musical realism. As stated- Whether it would be worth it to you to upgrade, would depend on the rest of your system, and your ears.

The affect is the emotion you feel when you listen.

Mlauner is on point,your source is always the most important component in the chain.It doesn't matter how sophisticated the equipment downstream,if you don't have a premiere front end you're just blowing smoke.

Jack
It's just getting better and better, huh?

All the above input is valid.

My exp is such that no one piece is more key than the source... but one wouldn't put a $5K CDP on a $500 INT amp, now would they? some sense of balance generally pushes things towards higher levels. The culmination of things allows the signal to be realized as being improved upon.

some will stick to spending more on speakers first and moving towards the front end (source), other's will think exactly opposite of that and drop tons on the front end.

The relationship between speakers and amp is pretty important, very, actually. once that is in place, either first or later on, or even last for that matter, the source is going to be where many go to get system wide gains.

simply throwing money on a source, without bringing up to par other pieces of your gear, you're spinning your wheels.

try out some new footers on that Cambridge... or play with it's power cord next. If you've not done that you aren't done addressing the source completely.

You seem to have liked what the new Cambridge did for your rig already. good. Perhaps now address some other area of your gear next. Maybe cables, or conditioning, even isolation.

My ideas are based on simply what I've exp'd. I've heard great sources, with great preamps and amps, on modest speakers, and it sounded beter by far than mid fi electronics on great ($$$$$) speakers.

Seemingly minor changes too, can be remarkably interesting and most positive... and fun.

Enjoy.