Audio Systems: CD player distortion, electromagnetic interference emi, rca cables

Question
Dan,

I was elated when I bought my first home a couple of weeks ago, but I've become increasingly aggravated since I connected my stereo system.  At my previous home, all components of my system operated beautifully.  At my new house, however, I encounter severe distortion when operating the CD player and DVD player.

The noise is present in any CD I play on either component and it's most pronounced in the high frequencies.  There's no background noise, but music sounds extremely muffled and filled with static.  The sound is similar to that of a clock-radio struggling to play at full volume even though my stereo's volume is turned down to a modest level.  Compact discs featuring consistently loud music (by Slayer, Jesus Lizard, etc.) sound especially muffled.

My turntable and tape deck sound great, therefore I doubt the problem lies with the speakers.  Also, the RCA interconnects are secured properly on all components.  Turning my attention to the amp and components, I thought poor grounding or a ground-loop might be the culprit. I replaced my extension cords and power strips with a heavy-duty surge protector and plugged all components into it.  The indicator light on the protector verifies it is indeed grounded, but that hasn’t helped solve my problem.

Now I suspect electromagnetic interference (EMI) might be responsible for the distortion.  You see, my interconnects, speaker wire and power cords are stuffed into a tight space behind my bookshelves and they’re tangled.  Do you think they could interfere with one another?  If so, how do I isolate the problem?  Are there ways to shield my components from EMI?  Would the addition of ferrite rings or clamps shield my system?  Should I replace my cheap RCA cables and power cords with expensive replacements?  Would shorter RCA cables reduce EMI?

I’m especially frustrated because my stereo sounded so wonderful at my previous home.  Plus, I can’t figure out why the distortion is only affecting two of my components.  Am I overlooking any other possible causes?  I would greatly appreciate your advice.

Thanks.

Equipment:
Sansui 7070 integrated amp/receiver (made circa 1978)
Pioneer DV-578A-S DVD/SACD player
Sony CDPCX455 400 disc CD Changer
Kenwood KD-21R turntable
Tascam 112 cassette deck
Infinity Reference 3-way floor speakers
Sony SAWX700 Active Subwoofer


Answer
I would purchase a can of electonics cleaner (make sure it contains a lubricant too) and spray the input selector switch.  With the receiver from the 70s, a common problem is dirty switches and controls.  Spray the switch contacts and work the switch back and forth a number of times.  Do this with the unit off.  Let me know if that resolves the problem.  If not, we'll look elsewhere.
Dan