Cable Suggestions

Look for a used pair of Cardas Quadlink 5C interconnects, which should be available in your price range. These will add some warmth, without loss of detail.

Other than Nordost, I have never know a cable to cause "too much high end." Try the $99 for 1 m. RS Audio Cables. They offer a 30 trial. I think they are truly exceptional and better than most $2k and above cables. I have two pairs thus far.

A properly shielded cable will likely help, as suggested by other inmates. Sounds like EMI/RFI emissioms from equipment/surrounding. The PBJs does not seem to be properly shielded.
Good luck.

Try some Acoustic Research directional cables from Bestbuy.com for around $13.00 a pair.Part numbers APO-30 and APO-31..take the rest of the money you saved and put it in some more sacds.Plug them up and be amazed at the perfomance!
Good Luck!

Shielding has nothing to do with it. Shielding will just increase the capacitance, which is not a good thing. Your problem is sibilance from poor conductor metallurgy. It is often perceived as high-freqency harshness or brightness. You need single crystal or perfect crystal conductors to eliminate this.

BTW - once you have good IC's and speaker cables, your components sibilance will probably stand-out, particularly CDP or Transport and DAC. Only mods will eliminate this.