Not loving my cambridge 740C

I run my 840c with Mogami balanced. Not expensive, maybe even 'budget', but I won't go back.....
I think it is the 'Gold' microphone cable...in 6 foot.

Interconnects are critical...I bought an 840C and found it blah and unexciting until I changed interconnects. Suddenly it became a keeper.

Not familiar with the other pieces but don't give up on the Cambridge. I doubt it is the problem as you describe it.

How many hours do you have on the amp, cd, and headphones? They could need to break in. The other issue could be your cabling. Interconnects, headphone cord and powecords. One of my friends has an 840c and at first it sounded very dry and analytical but after about a month of continuous play back it totally changed. It is now very magical. All the detail but also warm smooth, sweet and now it seems to have more dynamics with lots of slam. It took a very long time break in.