Help me figure this one out!

I have a 98 Max with an Alpine 7878 in the dash. I run a 4ch amp running mids and tweets actively using the onboard Xover. I have a seperate sub amp.

I fought with this car to minimize the whine and had it all but non existent. Big factor was isolating the Alpines dc-dc convertor from any car electronics in the indash.

I replaced my sub amp from a kenwood 150w to a jbl 300w running a custom box w/2 kicker comp 8". Now the whine is back. I played with the gain to no effect. I can hear the pitch of the whine shift when stepping on the brake at a stop with the level low.

Any ideas, change grounds, bad amp, maybe a broken rca during the change(don't think so)

Also the diversity antenae problem is driving me crazy. I thought I fixed this problem when I turned the adaptor plug around 180 degrees. I got my FM back and started getting some AM on the highway. This has decided to change performance intermittently.

Any help on either subject would be appreciated.

 

Possibles: bad rca's, bad ground, or power wire is to close to the rca's.

 

I hate to say this but the best way to test it would be to disconnect everything and then connect it part by part to see what it is that is causing the whining. but it seems to me that max'n out is right. first check that the wires are all intact and none are stripped, or cut in places. Another possibility is running wired next to a strong magnetic field like power wires or accessories that use a lot of power. Good Luck

 

Figured it out, boyz
The freakin, DC-DC convertor slip out of place under the dash and was hanging out the side of the console. near the gas pedal but not that low. I stuffed it back in and low and behold the noise level is negligable.

Thanks for the help. All of your ideas were valid, but the wiring was already in place from the previous amp that was quiet. That wiring was all seperate in the initial install.

This DC-DC box is going to get a MU-Metal overcoat....LOL