redmanV8

iTrader: (2)

I've run into a brick wall here any help will be appreciated . So my set up is;
Headunit : Sony gt56ui
Speakers : Alpine 6.5" spr components front, nothing in rear
Amplifier : JL Audio JX360/2
Wiring : DB Link 4 gauge power series

A little bit of information:'96 SC400 I installed the sony headunit, bypassed Nakamichi amp and used stock speakers. Everything sounded great until the speakers blew. So i decided to buy the alpine speakers and the JL amp to power them looking for a nice sounding setup.

PROBLEM ; After installing the speakers and amp i am hearing the dreaded alternator whine! Now, I've searched many forums on car audio and here as well but cant seem to figure out what is causing it. ive read that it can be numerous things that can cause the noise. i Have my amp under the driver seat, wires arent the best but i have tried pulling the stereo out as far as it reaches to see if i notice a slight difference, nothing. i tried relocating the ground wire on the stereo, nothing. could the amp be bad? i didnt hear any noise before installing the amp! If anyone can help diagnosing this? also want to know if anyone has a similar setup and what wires or grounding locations you guys are using.

SCereal

iTrader: (4)

Most of us install our amps in the trunk I think but you should be able to ground to the trans tunnel or floor pan as well. Just make sure you have a good solid ground. Scrape away the paint, use a proper terminal, bolt it down snug. 99% of the time alternator whine is a ground loop. see if your amp has settings for a floating ground and fiddle with that if you do. otherwise google for ground loop solutions and try those.

The SC platform isn't, to my knowledge, terribly difficult to work with for audio other than dealing with the gas tank situation which has no bearing on your situation. I don't think they're prone to any specific issues. Maybe someone more recently in the audio world can chime in, I'm a bit out of practice.

redmanV8

iTrader: (2)

ok thanks SCreal ill try to mess with the ground some more i have it on the bolt for the drivers seat at the moment

1UZ92SC

just installed a deck in 92 sc4. the factory amp is the issue. instead of speaker wire, they use rca/s that tap into the back of the deck. ground loop is correct. its eiher high seeking low or the opposite. ground to abs brain box directly underneath the deck, both speaker ground and deck ground. after that I am still getting alternator whine through all 4 speakers. I ended up getting a ground loop isolator. keep you posted.

redmanV8

iTrader: (2)

the thing is i bypassed the stock amp, used a sony deck and everything sounded great. once i got the jl amp and speakers installed is when i got the noise. today i tried different ground locations on the amp to chassis ,sanded paint, checked with ohm meter,still noise. i havent tried the stereo yet. im also thinking the quality of the speaker wire? i disconnected the speakers to amp in and noise went away. would it be safe to try and connect an ipod to the speaker wire going into the amp via headphone jack to audio cable? if this works then ill know for sure its the wires

SCereal

iTrader: (4)

if you have one, try plugging one of those headphone to RCA adapters and play something from your phone or ipod or whatever straight into the amp bypassing the headunit. Just turn the volume way down to be safe before you start. If you got noise, its your amp or down the line. If no noise, it's headunit or signal wires. that'll at least help isolate the issue.

1SlowSC400

Make sure that your main power wire is as far away from the rca cables as possible. That's usually where a lot of the alternator whine comes from. Also you could hook up an in line noise filter.

The2JZFTW

This X2. I ran my power wires on the driver's side, and the RCA/speaker wire on the passenger side. I've heard of the Nakimichi systems being harder to work with while upgrading, as the harness for the Pioneer has been figured out by raine already. Check out his tutorial if you haven't already. Got my whole system going thanks to him.

1SlowSC400

Also too be careful using your heater with the amp under the seat since there is that heater vent under there. You don't wanna overheat it. It might be a good idea to relocate your amp up under the rear speaker deck right above the gas tank and build a small amp rack. Pretty good location and plenty of spots to hook up your ground wire. And most definitely invest in a good set of wires, makes all the difference in the world

redmanV8

iTrader: (2)

Ok, today i ruled out the wiring by hooking up my cell phone to the speaker wire that goes from the stereo to amp, i did not hear any noise at all! i messed around with my phone moving it close to power wires and wherever interference can occur and didnt hear any noise at all crisp clear music. then i connected the speaker wire back to the stereo. i then looked at the stereo grounding wire moved it around, when its not touching a good ground source the engine noise is very loud but get it on a good ground and the noise is slightly fainter but does not go away! im going to try a different head unit i got laying around and see what happens. if nothing i guess ill need to get those in line filters

sc4hunnit

cut the tweeters out the equation. They are wired wieed and cause a whine.

SCereal

iTrader: (4)

Try this then if you still got it apart and it'll reach, put the head unit ground on the same bolt as your amp ground and see what that does.

The2JZFTW

The tweeters are fine. If it was the problem, it would still be there when he used his cell phone.

1UZ92SC

I believe the deck is a pioneer 64 or 6500 series.

Anyways. I figured out the issue. I had moved all the grounds to the ABS bolt body ground. Once I installed the filters, with no RCA ground I had sound and no whine, but missing mids. If I Grounded either RCA ground or RCA filter ground, I got all sound back, but the whine came back.

What I ended up figuring out was I had to complete the the ground path for the RCA's back to the factory amp utilizing the Metra adapter harness original ground for the RCA. Once I did that, and left the filters ungrounded it was fixed. Basically I had changed a bunch of grounds before I had the filters, installed the filters, scratched my head, and had to back up a few steps.

Stereo works, utilizing amp and stock wiring. Ground loops are a bish to trace.

kizzle

Here is what I did to remove the alternator whine. I have a double din pioneer and followed

Raine's tutorial and used the modified double din oem brackets.

If your using the metra harness. Do not splice the radio ground wire to the harness.

Ground it to one of the bolts inside. I used the oem metal brackets bolt and it completely

removed the noise. Or you can buy ground Loop isolators from radio shack or Bestbuy.


Edit:

didn't read whole thread.

Glad you figured it out.