unusual whining noise

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rjp9602@cox.net

Member - Posts: 14

Joined: February 13, 2007

Location: United States

Posted: February 14, 2007 at 9:59 PM / IP Logged

When I use RCA cables, the whine seams to be louder. I cut the factory harness off. Typically a harness kit would convert the factory harness to what is needed for the specific head unit. From the wiring kit coming from the Head unit, I use the speaker outs, and go to the amp, then the speaker outs on the amp goes back to the dash, which is where all of the speaker wires originate and go out to the speakers. So it goes out of the head unit through the speaker outs, spliced into speaker wire, which carries it to the amp, then through the amp back up to the dash, which then is spliced back into the factory wiring for the speakers. All of the factory speaker wiring is used, just with an amp in-between the head unit and the factory wiring harness. Does this make since, I am having trouble explain it.

Roland Prestenback

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DYohn

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Joined: April 22, 2003

Location: Arizona, United States

Posted: February 14, 2007 at 10:09 PM / IP Logged

OK, so you are using the high-level inputs on your amps? Generally this makes for much worse noise issues and much lower quality sound than using the line-level (RCA) outputs from the head unit to the RCA inputs on the amps. If this arrangement caused MORE noise, then either you have major ground issues, completely defective head unit or your amplifier gain is cranked to max. Is your gain cranked?

I the first thing you need to do is measure your ground return resistance and improve your grounds for the amps AND for the head unit if any of them read one ohm or greater. Do you have access to an ohm-meter? Then I highly recommend using proper RCA cables from your HU to your amps, and make sure your gain is properly set. If you do these things and still have noise, then you have a defective head unit OR a major issue with the car's electrical system.

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rjp9602@cox.net

Member - Posts: 14

Joined: February 13, 2007

Location: United States

Posted: February 14, 2007 at 10:15 PM / IP Logged

As much as I really do not want to say this, I am thinking that I have a major issue with the cars electrical system, after the shorting that happened that I mentioned above. I don’t have a clue what this will involve, but I have done almost everything else possible. I have grounded the amp and the head unit directly to the battery, this is also the 4th head unit I have tried (all pioneer) with this configuration. I don’t think that I am having an issue with grounds. The gains are turned all of the way down, but there is still a small whine. I would also prefer not to have to have the gains all of the way down, this means I am not getting the full performance out of the amp. The weird thing is that I was able to get the mp3 player to play crystal clear. The head unit will also play clearly when bypassing the amp. I will check the ohms tomorrow, I have a multimeter.

haemphyst

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Joined: January 19, 2003

Location: Michigan, Bouvet Island

Posted: February 14, 2007 at 10:29 PM / IP Logged

rjp9602@cox.net wrote:

The gains are turned all of the way down, but there is still a small whine. I would also prefer not to have to have the gains all of the way down, this means I am not getting the full performance out of the amp.

That is ABSOLUTELY not true. If your head unit can output enough voltage, then the amp will be driven to full output, no matter WHERE the gain is set.

What is the output voltage of the head unit, and what is the acceptable input voltage on the amplifier? If those overlap at all, then the amp can make full output. End of story.

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."

i am an idiot

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Joined: September 21, 2006

Location: Louisiana, United States

Posted: February 14, 2007 at 11:09 PM / IP Logged

I didn't read all of the responses to your post so if someone else covered this please forgive me for reposting it.

You need an ohm meter to do this. Unhook the patch cords and speaker wires from your amp. With the ohm meter put 1 lead on the shield of your amp's RCA inputs and the other lead on any 1 of the 4 non-bridged speaker wires. do this with each of your 4 RCA's if you get anything more than 10 ohms, there is a problem with your amplifier. It is an easy fix so let me know what you find.

gavin9797

Copper - Posts: 106

Joined: April 26, 2005

Location: Canada

Posted: February 14, 2007 at 11:37 PM / IP Logged

[QUOTE=rjp9602@cox.net]I have grounded the amp and the head unit directly to the battery,QUOTE]

If you have these directly to the battery (physically connected). Disconnect them, and ground your HU and amp to a clean piece of metal (no paint bare metal) on the vehicles chasis. An easy example may be where your seats are bolted to the floor. or the steel frame inside your dash.

t-roy81

Copper - Posts: 73

Joined: January 29, 2006

Location: United States

Posted: February 15, 2007 at 12:43 AM / IP Logged

do you have real good quality RCA's? thats a possible problem

Oh Man Theres Troy

rjp9602@cox.net

Member - Posts: 14

Joined: February 13, 2007

Location: United States

Posted: February 15, 2007 at 6:17 AM / IP Logged

Alright, let me see if i can answer these. For the grounding of the amp, i have it grounded to the bolt of the seat, I have ran a 4 gauge wire directly to the battery as a test, nothing. I have had the headunit grounded to the metal frame, as a trial, i ran a wire to the battery. Neither made a difference. I have fairly decent rca cables i guess. They came with the wiring kit. I am still a little confused about how to check the ohms as mentioned with the ohm meter and such.

rjp9602@cox.net

Member - Posts: 14

Joined: February 13, 2007

Location: United States

Posted: February 15, 2007 at 10:13 AM / IP Logged

My particular head unit puts out 50x4 watts max i suppose. it also has 6 rca outs.

xtremej

Gold - Posts: 1,440

Joined: February 24, 2006

Location: United States

Posted: February 15, 2007 at 3:23 PM / IP Logged

you mean 3 rca out puts? they are in pairs left/right. Not to hurt feelings here but IMO you should take this vehicle to a professional and have the stereo system re-wired. I have read these posts and it seems to me your are like a dog chasing his tail. Before you kill anymore amps or cd players I would spend the money and have someone that does car audio for a living figure it out.

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