bromy2000

Hi there been suffering from alternator whine for a while, tried everything to sort it new rca. checked all earths tried eathing everything

so i gave up bought a earth loop isolater did nothing, so as a last resort i tried to connect a temp battery to the amp as that was the only thing left to try and with amazment no whine at all.

so how do i sort this its obviously power lead related, but i havent got a clue on where to go from here i tried a new power cable, also tried running it from outside the car makes no difference, and i tried giving the battery a better earth.

Its driving me crazy wish id left it standard lol

RMA26

Power Cap?

RMA26

Are your RCA's and power cable run down each side of the car, seperate

(apologies, had to ask the most obvious question)

chiark

Power cap will do nothing.

The one thing you've changed is the grounding of your amp which makes me think that that is connected with your problem. Can you describe your setup in detail, please?

bromy2000

RCA's are down the right hand side power lead down the other.

rite ive a got a Phoenix Gold ZX450 powering a set of front infinity components and a vibe sub with its own amp but i have disconected that at the moment until the problem is solved,

head unit is a is a Pioneer AVIC-X1BT Navigation Unit

bromy2000

didn't realy fancy fitting a Suppressor but it looks like thats my last option, would this cure the problem completly or just make it less noticeable??

tyron.c

i had a whine after fitting my ice.
I added some extra earth leads, one to battery from chassis (nr battery), and one from battery to inside of car, also to chassis.
Problem solved!

bromy2000

Tried a few earths to the body doesn't seem to help, such a pain in the ****....

ru'

You could try running a cable direct from the -ve of the amp to the battery -ve terminal to see if that sorts it; if not then it's not an earth problem on the amp...

bromy2000

tried that too mate think the only thing left is a suppressor, as when i connect the amp to another battery its fine so it must be getting inteference through the power cable ..

Henrik

iTrader: (5)

Ooh, my favourite (not!) topic... I have been battling with alternator whine for a while also

You should be able to isolate where the noise enters the system by disconnecting equipment in order until the noise disappears.

Start at the head unit and disconnect the RCA cables from the head unit. If the noise disappears, then it's likely that the head unit is the culprit.

If the noise is still there, disconnect the RCA's at the amp end. If the noise disappears, then the RCA is knackered.

Continue doing this until you find the faulty piece of equipment (i.e. if you have active filters etc etc).


I used to have a lot of alternator whine, but after changing the earth lead between the engine and the battery and the battery and the car body to some 4 AWG wire there was significantly less (It's not completely gone, but a lot better than it used to be). Also, you could change the wire that goes from the alternator to the positive pole.

My own head unit has a really, really crappy filter on the power input side, which means all the noise in the electrical system is propagated through the RCA cables. An RCA noise filter was a cheap fix for me until I can afford a better head unit, but it does not do wonders for sound quality.


So, in conclusion, try disconnecting the RCA's at the head unit end and if the noise goes away, it's prolly the head unit. Otherwise, disconnect the RCA's at the amp end and if it goes away then it's the RCA. Otherwise it's the amp that needs a better power supply

Henrik

iTrader: (5)

Btw, when you connected the second battery, where was the amp and second battery earthed?

bromy2000

i did that when i disconnect the RCA's from the head unit the whine goes away, and it goes when i disconnect them from the amp too.

so im i rite in thinking i can put it down to the power cable or could it still be something else?? im lost i really don't know what else to try.

bromy2000

amp was still earthed to the car (rear seat bolt)

temp battery was earthed to the same point as the current battery!!

ru'

As per post above, if the whine goes away when you disconnect the HU from the amp (and when you disconnect the RCA feed to the amp) it suggests it's your head unit.

What's the power feed and earth like to the HU?

Also, what's your gain structure? If you have a low output from the HU, and have to turn the amp input level right up to make up for it, then any noise/whine etc. picked up in between will be amplified.

How is it all wired up? Are there separate pre-outs for the PG amp and for the sub amp?

bromy2000

power feed and earth is from the standard loom, tried a better earth to the head unit made no difference

the pg amp has only one set of RCA's which run the front speakers.
the sub is a vibe active with a built in amp which has its own set of RCA's
but i have disconnected the vibe sub/amp so i can eliminate this as the problem

the gain on the amp is set to minimum!! i have also tried it at different levels, makes no difference.

is there anything else i can try head unit end? its only been in 2 weeks shouldn't be a problem with it, and it is sounding alot like this could be the cause..

cheers for the help.

bromy2000

spent days on this now and i think im finally getting somewhere.
when i ground the RCA's at the head unit end by touching them with an earth whire the noise go's

so does this mean its the head unit earth thats causing it?
does anyone have any ideas as the cars is in bits for the last time.


ive also tried a groung loop isolater and a suppressor makes no difference.

evolutionice.com

Jeez !!

Cut the earth wire at the headunit and run a new earth wire, from the same point that you earthed the amplifier, to the head unit.

Alternator whine (Ground Loop) is caused by a difference in resistance between to earth points. If you earth all the audio components at the same point then the resistance will be the same. In 12 years of installing car audio this is my standard practice and i have never had an ground loop problem.

bromy2000

Problem found. the ground track has gone in the head unit so ive had to earth the rca leads thank god thought id never find what it was.

Thanks for all the advice..


Chris

evolutionice.com

that means that your amp has had a bad earth point at sometime.

WRX RCY GEM

How do you earth the rca leads ?

evolutionice.com

run a wire from the outer part of the plug to a suitable ground point.

ru'

I think you can buy them. You 'could' (depending on type of cable etc.) carefully remove a bit of the outer insulation to expose a small section of the screen and solder a wire to that screen. Easy to melt the insulation by accident etc.

bromy2000

just run a earth wire to the RCA lead, stip enough of the wire to wrap it around the shield of the rca a bit of electrical tape ... job done whine free.