Factory 8 track with 1500W amp

[timmycharger]

Many years ago I had my factory 8 track rebuilt by a place called Barry's 8 track service.  Aside from cleaning up  the insides and changing the belt, he also wired in a headphone jack and amp outputs.  I have high end Sony speakers mounted, 2 in front, 2 in the rear.

I have been using a tiny motorcycle amp for years since installing and it sounded tinny and horrible.  I finally installed a proper amp over the weekend and have promising results.

The good news:  With the car not running, I get really impressive sound with both the 8 track and the headphone jack (ipod), I mean it is really loud and clear, what I thought was impossible with an 8 track, very impressive actually. 

The bad news: As soon as I start the car I get a loud humming/buzzing out of all speakers. Only way to cure it is to unplug the RCA cables from the amp and I get no sound.

I installed a Blaupunkt 1500W 4 channel amp in place of the tiny 4ch amp I had there before.  The wiring is pretty straight forward, heavy gauge wire for power and ground, high end speaker wire used. 

Here is where it gets a bit sketchy.  I Assume that the 8 track amp outputs are just left and right (white/red) (pic shown), so I have splitter adapters to make 2 outputs into 4 to plug into the amp.

Is there a way to suppress the buzzing sound with some sort of RCA noise filter? anyone have any experience with that?  If I can get rid of the buzzing, I will be so happy as I cant believe how loud and clear this 8 track player is now.

Also, pic of some of my 8 track collection 

[timmycharger]

Did some research into the humming/buzzing and many people were able to solve their issues by making sure everything was grounded properly including the head unit and then making sure that the signal wires (rca cables) are not touching or near any power wires.

Looking at the pic above you can clearly see that not only are the signal wires near the power wire, it is literally zip tied to the main positive cable going up to the starter from the battery in the trunk.

I did a quick test with a different set of signal wires run loose outside the car, not touching anything and the buzzing/humming almost was completely gone so I think I am on the right track.

Regarding the ground for the 8 track radio, I believe that is good too because of that strap/bolt that holds the radio in place, that goes right to the body, should be no issues. 

The amp is grounded well, you can see in the above pic, the thick gray cable that goes to a bolt in the dutchman panel/trunk hinge support area. I used star washers and grinded off the paint to bare metal.

[b5blue]

Read here: https://www.bcae1.com/