alternator whine from all speakers

One day while driving, my stereo began to make loud popping and scratching noises (very loud). The next day, I traced the problem to be a loose + speaker connection at the drivers side door that was touching metal, and resecured it to the speaker terminal again. Then I turned on the car to test it, and all of a sudden I got this loud alternator whine coming from all speakers.

I already checked the grounds at my amp and HU (Kenwood KDC-589) and they are all good. The RCAS (no were near Power components/cables) are good, as I ran a test with a set of external RCAS from the HU to the amp, and the whine is still there. The only time the whine is gone is when i umplug the RCAS at the amp... What could be wrong? (The only time it did make alternator whine before was when the car was on, and I manually turned the HU off) but other than that my system never made noise, until this little incident. Any help would greatly be appreciated. Thanks

http://bcae1.com/images/rca/temporaryrcashieldrepair.html

Perform the test at the top of this page.  If the resistance is greater than 100 ohms, you need to get your deck repaired, or follow the instructions beyond the test.

If the radio checks out, do not waste your time with the procedure beyond the test.  What kind of amp do you have?

UPDATE: PROBLEM FIXED!!

Thanks to "idiot", I found out that my rca inputs at the deck werent grounded anymore. I did the "temporary fix" and worked like a charm!! Sounds real quiet again. Thanks.

Btw: My amp is a 4ch performance teknique icm-774

Glad to help, and Thank You for letting us know that you got it fixed.  We get a lot of new ones that get their problem fixed and just dissappear.