alternator whine with alpine pdx amps?

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=107866
Printed Date: May 28, 2024 at 4:59 AM

Topic: alternator whine with alpine pdx amps?

Posted By: shagdrum
Subject: alternator whine with alpine pdx amps?
Date Posted: October 01, 2008 at 10:59 PM

I just installed two Alpine PDX amps in my 1996 Lincoln Mark VIII (a PDX 4.100 and a PDX 1.600, to be exact). At first, they had no issues, everything sounded great. Then after about 5 days, I started getting alternator whine. Usually when I hit a bump it would start, I would hit another bump and it would stop. The amps are mounted to MDF in the back, and not screwed to the car (and possibly grounded). I went in and resecured the RCA's as far away from the power wires as possible...still getting whine.

Is this a problem with the amp? Is this an issue with the PDX line?

FWIW, I think my alternator may be going out as well. The voltage is around 12.5 to 12.9 when idling right after starting. I have done the whole "big 3" upgrade to the car and it has a new battery. Can a bad alternator cause alternator whine in the system?

Thanks in advance for any input.

Replies:

Posted By: haemphyst
Date Posted: October 02, 2008 at 7:49 AM

I have three of them, and I haven't had any noise... You most likely have a grounding issue somewhere. I m pretty sure of this, because you said that it comes and goes with bumps... Recheck all of your grounds, deck too.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Posted By: shagdrum
Date Posted: October 02, 2008 at 1:54 PM

Both amps have their ground wire running into a ground block and then one larger 1awg wire that grounds that block. Could the RCA's be grounding behind the headunit?

Posted By: shagdrum
Date Posted: October 02, 2008 at 4:28 PM

The deck is the clarion MAX685BT

Posted By: haemphyst
Date Posted: October 03, 2008 at 7:42 AM

Where is the ground connected? (Seat bolt a no-no) Big 3 done? All grounds in the car tight and clean (especially battery, engine and alternator grounds)? Alternator age and quality? Battery age and quality? Ground on the deck? RCAs good and tightly connected at both ends?

These are some of the things I would look into to start with, but I think you are seeing a pattern there... posted_image

I can't say that the PDX amps are necessarily more sensitive to grounding issues, but I do belive that you have a ground issue somewhere.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."