Replace Silver interconnect cable , please advice

right , they are brand new
are you sure that might be the issue?

not a DAC maybe or room acoustic or speaker standing?

the acoustic zen silver reference ii XLR should be good enough for my system?

I see 2 things you may want to look at. First is break in. Cardas takes a very long time. Second is your PC. There's a very good chance setup is not as good as it can be for audio. If you haven't already done so, try comparing a ripped CD played through your computer, to playing the actual CD in your Oppo. See how big the difference is.

I would guess it probably has to do with your speaker placement over anything else. That is really good gear you have there. Your source is probably the weak link if you have one. Acoustic Zen Silver ref is a good cable. It's not the problem at least not to the degree you are describing. Some rooms are very tough to get good sound in.

Also possibly something could be amiss with your computer setup and delivery to the DAC? Have you tried just playing CDs in the Oppo?

If you are looking for a different flavor you might try Grover Huffman cables. They are very cables and a great bargain too.

Ejlif:
"Your source is probably the weak link if you have one"

you mean the DAC (oppo) or the PRE ?

when i play CD it's much better then the computer
but even then it's not so good.
i even though to replace the speakers with Utopia Scala or something else.

make sure your speaker settings in the oppo are correct for two channel listening with no subwoofer.

If the pc and oppo is your only source, you mayhave a setting issue in he oppo.