It's possible that what you're hearing is distortion caused by stacking of low quality materials in the product, e.g., PSC wire, polyethylene primary dielectric, etc. I wouldn't have these in my system.
If you can't live with the sound, recommend you switch to a cable made of OCC copper wire (not OFC), FEP Teflon dielectric and copper (not brass) plugs. There also is OCC silver wire, but it's brighter, and probably not for you.
Acoustic Zen Matrix Reference II is a good cable, IMHO. Beware of AZ fakes being sold as 'demo' on some audio websites. Also, if located in Europe or Canada, look for Atlas Cables, e.g., Titan which is similar to the Acoustic Zen Matrix Reference II.