please help: noise, hiss, buzz problem

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=20217
Printed Date: December 20, 2025 at 4:27 AM

Topic: please help: noise, hiss, buzz problem

Posted By: knn444
Subject: please help: noise, hiss, buzz problem
Date Posted: October 16, 2003 at 10:03 PM

Hi, I've recently finished installing a computer stereo system in the 2000 GS400 but couldn't get rid of the hissing/buzzing noise from the front & rear speakers. For almost a month, I've searched/read from many forums and tried all the tips/suggestions but still couldn't solve the problem. Here's my system setup:

Battery: Optima Yellow 34/78
Power Supply: Opus 150W DC PSU (a flip-switch and a relay were used between the ACC and PSU)
Computer: EPIA M 1000 (installed in glove compartment)
Monitor: DSCustoms TouchScreen (powered by Opus)
Soundcard: SB Extigy USB (powered by Opus)
Amplifiers: Kicker 600.4 and Kicker 1200.1 (installed in trunk)
Speakers: front: Focal 130V components, rear: CDT 61 components
Subwoofers: two Infinity Kappa Perfect 12.1 DVC in a bandpass enclosure
Wirings: Stinger power and speaker cables, Monster Cable 20-ft "mini 1/8" to RCA" cables

From reading from various posts and tutorials, I thought the noise is caused by a ground loop. But the noise was still there even when I connected the power & ground of the Kicker 600.4 amp directly to the pos. & neg. battery posts, all the settings were set to minimum and the signal input was muted by this method (https://akamaipix.crutchfield.com/graphics/infolib/carlib/Amp-diagnose.gif).

Can I assume there should be NO noise if the amp is grounded directly to the battery instead of car metal chassis? Will installing a capacitor help? Is running a long GROUND cable from battery to trunk recommended?

I would really appreciate your replies with any hints, tips, suggestions, etc. Please help ending my nightmare :D!!! Sorry for the long post.

Replies:

Posted By: nedgeworth
Date Posted: October 16, 2003 at 10:27 PM

Have you tried using different rca's and connecting a discman to the amp and seeing if the problem is still there? If it is still there most likely you have a problem with your amp. Otherwise it could be a host of other things.

A capacitor won't do anything to help get rid of any hissing. My advice is check carefully over all your connections.

Posted By: bfog99
Date Posted: October 16, 2003 at 10:44 PM

How long is your ground? The shorter the better. It might be worth your time to try a different ground that is shorter. Make sure that there is no paint on the metal where you are grounding to.

Posted By: knn444
Date Posted: October 16, 2003 at 11:15 PM

The noise is there even WITHOUT any sources/signals input to the amp. I also eliminate the speaker wiring problem by not using the existing connections, I tested with a separate 2-way Kenwood speaker.

My grounds are all about one foot, I did sand and clean any metal chassis that I connect the grounds to.

I read an article somewhere suggesting that for a multiple-amp setup running a ground cable directly from the battery to the amp(s) just like running a power cable. So is it safe to assume there should be minimal to no noise if the amp is grouned to the battery, which prevents the ground loop problem. I think the Kicker amp is the problem, I'll try some other amps to find out.

Thanks for your quick responses.

Posted By: nedgeworth
Date Posted: October 16, 2003 at 11:25 PM

Yeah from the sounds of it i think you have a bad amp there. So if you can do the same tests with your other kicker amp or another amp you can get your hands on that will give you the insite.

There is no need to run the ground straight from the battery as it sounds as the problem isn't a bad ground if you connect it directly to the battery and have the same problem. So your current ground situation is fine.

Posted By: Ketel22
Date Posted: October 17, 2003 at 12:15 AM

i have the same problem in my home amp, im just too lazy to fix it but its basically a bad ground in the RCA input on the amp

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Posted By: Sound World
Date Posted: October 17, 2003 at 8:56 PM

Give this a try. Get a cheap 1/2 meter RCA, 2 female to female barrell conectors, and at the 600.4 remove either the front or rear RCA input doesn't matter which set, and attach the 1/2 meter to it (leave the other set plugged in). Now on the cheap 1/2 meter RCA strip back the shield on it so its no longer connected with the RCA plug. Now you should just have the center pin of the RCA left on the cheap 1/2 meter plugs. Plug it in and see if it helps at all. I'm not sure if this will help, because you said the noise was there when no signal was at the amp, but it sounds like you tried everything else, so it may be worth a shot. Do not hack your nice Monster Cable RCA's. A Kicker tech told me to try this if you have ,hard to eliminate, noise and all other ground loop causing issues are fixed. If you give it a try, let me know if it helps at all.

Posted By: auex
Date Posted: October 17, 2003 at 9:59 PM

IMO it is the power supply. Have you disconnected the rca's and is it still there? How close is the power supply to the amplifiers/rcas?

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