Amp and Cap, Separate Ground Points?
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=72700
Printed Date: July 06, 2025 at 5:41 PM
Topic: Amp and Cap, Separate Ground Points?
Posted By: remarkable53
Subject: Amp and Cap, Separate Ground Points?
Date Posted: February 12, 2006 at 4:54 PM
Every single instruction booklet say that the amp and cap should have seprate ground points? Why? the grounding potential is the same if it is only what 8-12" away? I have never really got a straight answer. Anyone care to venture a guess?? But if you read every installation manual everyone I have seen say the same thing Ground the cap and amp at seprate spots?
-------------
remarkable53
Replies:
Posted By: DYohn
Date Posted: February 12, 2006 at 5:05 PM
Because a cap is a very noisy beast and can send that noise back through the ground wire into the amp, corrupting the signal. ------------- Support the12volt.com
Posted By: kjonas
Date Posted: February 12, 2006 at 11:20 PM
Hi, I was under the impression that a cap cleans nosie. I have my amp and cap connecting to the same ground and cannot hear distortion. I use 4 gauge wires and my cap is about 30 cm from the amp. I get no resistance for the ground conection. I got no manual for my cap
Posted By: jlord16
Date Posted: February 12, 2006 at 11:26 PM
If you want to use a common gound source just use a distribution block and have one ground point
-------------
Clarion DB36MP
Infinity Kappa Perfect 10"
Respone 800w Mono
ALPINE MRP-F250
*Custom fabrications*
Posted By: coppellstereo
Date Posted: February 13, 2006 at 1:06 PM
Caps do not clean noise out of your signal or power.
-------------
Posted By: Paradigm
Date Posted: February 13, 2006 at 1:19 PM
kjonas wrote:
Hi, I was under the impression that a cap cleans nosie. I have my amp and cap connecting to the same ground and cannot hear distortion. I use 4 gauge wires and my cap is about 30 cm from the amp. I get no resistance for the ground conection. I got no manual for my cap
Caps don't clean nosies, either  . Sorry, that just made me laugh. It's always good to have a laugh every now and then. Just givin' ya a hard time, eh? ------------- VEHICLE: 2002 GMC Sonoma ZR2
Alpine CDA-7940
AudioControl EQT x2
JL Audio 1000/1
JL Audio 10W6 (originals) x3
Kicker ZR120
Kicker ZR460
Polk GXR-6 x4
Polk GXR-4 x2
Posted By: kjonas
Date Posted: February 15, 2006 at 5:08 AM
Hi, Just came across this article here. https://www.mmxpress.com/technical/capacitors.htm It said said :- Another benefit of the large capacitor, is that as we mentioned, it passes high frequencies. Any electrical noise will be filtered by a capacitor since the noise is AC. In addition, since the capacitor is a large one, then the "high" frequency can actually be pretty low. In this manner, a capacitor helps reduce power supply noise in your audio system. So according to that article a capacitor does clean the signal (or am I not understanding something). As I said before I don't have any nose in my setup (usingsame ground for amp and cap). Can anyone explain the article and if it is incorrect or not ? KJ
Posted By: haemphyst
Date Posted: February 15, 2006 at 3:16 PM
That article is absolutely correct. A capacitor will server as a ripple (noise) filter in a DC system. As the article said, the AC component (the ripple) is effectively shorted to ground THROUGH the cap, while the capacitance helps to "fill-in" the low voltage points of the ripple. coppellstereo, I was wondering who told you that caps don't filter?
Have you ever looked inside a power supply - ANY kind of power supply, and seen caps? Those are doing the SAME thing as a 1F cap would do in your car stereo, just with lower values, due to the potentially smaller current demands... Yes, caps DO filter.
As far as the original question? Common ground is perfectly acceptable, and IMO, preferred... Fewer connection points, shorter conductor paths (the chassis IS a conductor, albeit a HUGE one)... I built two rails, and mounted the caps DIRECTLY to them, AND made compression (set screw)fittings for the power cables, both in and out, power and ground. I have ALWAYS used a common ground connection point for caps and amps. I am STILL not saying there are many benefits to caps, but IF there are, common sense tells you to make the electrical path as short as possible.
-------------
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."
|