Head scratcher.... am I missing something?

[garychoffmann 10+ year member]

Well, I went out to my project car to work on the stereo. I installed my ppi a404 and a1200. Fired it up and a lower pitched pulsating hum coming out of all of the speakers. So I start trouble shooting. Voltage is great, grounds are extensively grounded. Head unit output is perfect. Everything checks out. I had the amps rebuilt about a year ago so I thought maybe its an amp issue. Hooked the amps up in my truck and they sounded beautiful. Took my directed 1100d5 and put it in my car.. it sounded perfect. Took the ppi's out of the truck and back in the car. Noise is back. I drop the amps off at the guy who rebuilt them and had him test them. Checked out perfect. So I check for an rca issue and voltage/sine look perfect. To double check I use my Yamaha receiver and run rca's to the amp. Hum is there still. I'm stumped so I start swapping in other amps. Put in a t2500.1, a600, phoenix gold 475ti, junk Sony 4 channel, a cobalt 260. Everything worked perfectly. Now here is where it gets interesting. I put another a404 in there and it was a little better but was there. Put in an old ppi sedona and it was there. Sooo my conclusion. Ppi hates my car. I can run anything but these ppi's. Any ideas? I'm plum out.

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[Side Show 10+ year member]

rca ground loop issue, does the sound go away when you take one of the rca's going into the 4channel out?

 

[garychoffmann 10+ year member]

Its actually electrical feedback. Not sure what part of running/monitoring systems of the car where making the trouble but it looks like it will be getting gutted again lol. Engine is coming back out anyway. Oddly the ppi's are the only ones that picked it up.

 

[Braindead]

Did you run your power and rcas on the same side of the car, also did you possibly strip your rcas on the chassis and now they're grounded?

 

[garychoffmann 10+ year member]

Its just the ppi's. But no, the power runs are ran through a c channel under the car. The rca's are loomed and ran center. Grounds are crimped, bolted and tacked then coated.

Its electrical feedback. In the power itself. It goes way beyond my electrical understanding. Basically my circuit that had my stand alone, gauges, sensors etc, basically the running and monitoring of my engine, was emitting nasty interference. Into the power line. Since that line was connected to the battery, connected to the charging system, etc it made its way to the amps. The ppi's were the only ones susceptible to transferring the noise into the signal.

It took a guy with the knowledge and high dollar equipment to find it.

 

[Side Show 10+ year member]

so how did you fix it? is it fixed>?:

 

[StrygwyrBS]

this sounds like the exact issue i am having on my thread. please let me know how to fix it! I'll send you a link to my thread!

http://www.caraudio.com/forums/wiring-electrical-installation-help/592526-distortion-problem-subs-produce-continuous-sound-while-deck.html

 

[garychoffmann 10+ year member]

I have to isolate the ecu/coil/injectors. On a factory produced car they have measures in place to help with the electronically created interference. My engineer friend is helping with a wiring diagram. I used massively oversized wire in my engine and ecu related components.

 

[imghetto]

I'm in Australia but i'll have yr PPI's that'll fix yr problems lol. I got an A1200, A600 and A404 already so a few more won't hurt I've got the room for them

 

[Jepalan]

Where are the PPI's physically placed in the car? And where are they in relation to other amps and the speakers?