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Ground Loop Isolators + Amps.

nsanity

By nsanity,
in Car Audio & Electrical

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nsanity Rising Star

nsanity

Posted
Posted

Hey,

Just wondering if i've had my chain pulled here.

I recently just put a nice Stereo in my R33 Skyline, Unfortunately there is noise coming through the speakers. I corrected this through a Ground Loop Isolater (Headunit -> Isolator -> Amp via RCA).

Whilst looking for one, i was advised by a car audio place that my amp should already clean this up, however the guy who did the install (and is held in reasonable regard around here according to a SAU ACT member) mentioned that it was a particular problem with R33's and BA Falcons.

Who is telling the truth? should my Cadence FX500 5 channel amp filter it out? or are R33's a noisy bugger and require more?

Is there a better (and cleaner sounding) solution than the $15 part i bought from AutoBarn?

Cheers,

Geoff

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Chris Rogers Grand Master

Chris Rogers

Posted
Posted
Hey,

Just wondering if i've had my chain pulled here.

I recently just put a nice Stereo in my R33 Skyline, Unfortunately there is noise coming through the speakers. I corrected this through a Ground Loop Isolater (Headunit -> Isolator -> Amp via RCA).

Whilst looking for one, i was advised by a car audio place that my amp should already clean this up, however the guy who did the install (and is held in reasonable regard around here according to a SAU ACT member) mentioned that it was a particular problem with R33's and BA Falcons.

Who is telling the truth? should my Cadence FX500 5 channel amp filter it out? or are R33's a noisy bugger and require more?

Is there a better (and cleaner sounding) solution than the $15 part i bought from AutoBarn?

Cheers,

Geoff

both are VERY noisy cars - though if you do the wiring correctly that wont be a problem. what you have is a quick fix and works. it will also roll the VERY low bass off quite sharply.

so of the amplifiers have better input stages than others but to my knowledge none of them have inbuilt RCA chokes. (on th PSU they do.)

nsanity Rising Star

nsanity

Posted
  • Author
Posted
both are VERY noisy cars - though if you do the wiring correctly that wont be a problem. what you have is a quick fix and works. it will also roll the VERY low bass off quite sharply.

so of the amplifiers have better input stages than others but to my knowledge none of them have inbuilt RCA chokes. (on th PSU they do.)

What would your suggestion be to rectifiy this?

I only have the Ground loop Isolator on the Front/Rear Channels atm, the Sub is unfiltered.

Spook33 Enthusiast

Spook33

Posted
Posted (edited)

could be your head unit.

i had a really bad alternator whine when i put my stereo in a while ago (pioneer HU, Alpine splits and 6*9's and cadence 4 channel) tried every thing to get rid of it in the end sold the pinoneer HU and brought a good Alpine one and the noise was gone don't know why ?? but i;m happy

Edited by Spook33
nsanity Rising Star

nsanity

Posted
  • Author
Posted
could be your head unit.

i had a really bad alternator whine when i put my stereo in a while ago (pioneer HU, Alpine splits and 6*9's and cadence 4 channel) tried every thing to get rid of it in the end sold the pinoneer HU and brought a good Alpine one and the noise was gone don't know why ?? but i;m happy

I just spent ~2100 on the stereo, the head unit is a middle-ish range JVC KD-G725 unit. I'm quite attached to the USB input to be honest, if i can get the noise filtered properly, i will do magical star jumps.

Chris Rogers Grand Master

Chris Rogers

Posted
Posted
What would your suggestion be to rectifiy this?

I only have the Ground loop Isolator on the Front/Rear Channels atm, the Sub is unfiltered.

if you can pull the rears off and stick a shorting plug in place then move the isolator to the sub channel as a temp measure. if it works buy another one. to do it properly would require a TOTAL strip and rework.

Chris Rogers Grand Master

Chris Rogers

Posted
Posted
could be your head unit.

i had a really bad alternator whine when i put my stereo in a while ago (pioneer HU, Alpine splits and 6*9's and cadence 4 channel) tried every thing to get rid of it in the end sold the pinoneer HU and brought a good Alpine one and the noise was gone don't know why ?? but i;m happy

unlikely but possible. only way it could do this would be if the amplifier earth was loose. that in turn would destroy the earth tracks on the unit.

try what I suggested first.

  • 3 weeks later...
nsanity Rising Star

nsanity

Posted
  • Author
Posted (edited)

JVC deck actually.

that being said.

the problem is intermittent. I can't put my finger on how to get it to make the noise.

Example. Roughly about 23-24 on the volume will be enough to drown out all but 5000 - 7000 rpm of exhaust engine noise.

When it is behaving, i will not hear the whine after about 4 (very quiet) - sometimes i can't hear it at 0.

When its usually being annoying, i will hear it till about 14.

When its absolutely f**ked i will hear it till 27 - 28.

I have a Stinger GLI, should i get that earthed (the shell) as well? The system sounds awesome, its just that when its playing the whine - i just turn it off because it makes my head want to explode.

Edited by nsanity
dangtstr32 Apprentice

dangtstr32

Posted
Posted

My mum had this problem in her car. i rewired it to make sure the rca's where away from the power cables, that didnt make any difference. Then my dad played around with it and he had it unmounted and it wasn't doing it, in other words the metal body of the car wasnt touching the metal body of the amp and that fixed it. We ended up using velcro and mounting it to the carpet.

Good luck

ToF Experienced

ToF

Posted
Posted
you dont have a pioneer deck do you? they absolutely hate skylines!! if you have pioneer its your problem

Huh? I just installed my Pioneer deck with no noise or problems at all. Completely new wiring and all. Don't know what you're talking about. >_<

nemz Experienced

nemz

Posted
Posted

i have found an easy solution which should work, which is quite simple, simply attach a small wire to the rca's where they plug into the amp, if your not sure what i mean, the lil metal tip which goes in her hole!! then ground them, does not seem to matter if they all grounded together, solved my problem

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