alternator whine

[redrunner]

hi, ive just upgraded my car radio amp and cant get rid of alt whine
ive simply swapped it over for the one that i fitted 3 yr back that came with matched up speakers and proper wiring kit etc which worked fine
the one ive just fitted is a -shark Z-4000- 1600W 4 CHANNEL
dont know if there a good amp or not ?
its got main feed from batt with 40 amp inline fuse
and a good solid earth to chassie
i fitted a 3.0 microfared capicitor to alternator made no difference
even with no head unit connected to it i get the whine as soon as i start engine
which increases with engine revs
ive tried grounding it other places and even tried a quick try + live feed from ignition ,
also moved the amp to the boot [ its under passenger side normally ]
made no differnce
apart from swapping back over again any advice/help / is welcome
regards.r.r.

 

[Peter.N.]

The only thing I can suggest is that you have a high resistance somewhere in your battery circuit. Check and clean the battery connections and also the earth lead which will be on the engine or gearbox. The only other possibility I can think of is that your battery is faulty.

Peter

 

[Burnerman]

Halfords do an in line filter that connects into the 12v feed to the audio unit.....there is a possibility though that its the ECU thats causing the interference.
John

 

[redrunner]

thanks peter.n. and burnerman
battery terminals are clean and tight, battery about 6 months old
will get earth straps checked when me mate ramps it next week to put new gearbox linkage on
but the car doesn't have any charging /starting issues
alt puts 13.5 v out with everthink switched on
i will put an inline filter on audio input line
you could be right about the ecu burnerman
being wiser afterwards its not fitted in best place its under glove box passenger side not 10 inches from ecu on mk5 escort
but never had any problems with other amp fitted there, but of coarse this could be more sensitive as it still picked it up when i tried it in the boot
thanks for prompt replies.r.r.

 

[stuartturbo]

First disconnect the feed from the stereo, Are you using pre out's or from the hi level input ( speakers and a convertor)
try at both ends as the pre out leads may be picking up the interference.
also try a separate amp on source temporally
what is the S/N ratio at least 95db helps
and how much was the amp i haved not heard of them but been a while.
I never suffered alternator whine on any of my "excessive systems"
Quality amps alpine, infinity, mtx ,kenwood rochford etc
a quick Google and nothing comes up so does not look to good for a quality amp.

The big thing if you put the old amp in the whine goes away??
Try turning the gain down on the amp also as it may be driving to the max so whine becomes worse.
max sure preout run on different side to the power. I run power up sill an all speaker,amp imputs up the middle so when the cross it will be a 90degrees

 

[bhm1712]

make sure the power cables are not routed alongside the speaker cables. This will cause interference. You can also shield the power supply cables and earth the shield which will keep radio frequency alternator whine to a minimum.

 

[Burnerman]

I must be getting on a bit.....I've only got my radio tuned into Radio 2 and I haven't used the CD player yet (56 plate Berlingo van)
John

 

[Peter.N.]

Me to, I only have the standard radio/CD in the 406 - and the CD doesn't work

Peter

 

[redrunner]

sorry late reply,
stuartturbo- hi/ head unit uses pre outs from radio to amp
not sure what you mean about s/n ratio or how to check it ?
the amp i spotted on ebay when i was looking for somethink else , it was £40 and new so i bought it without doing a google on them
but as you state they do not show on google as i was looking to get answers from there
as for seperate amp if i put old one back in same cables same place etc. no probs .
cant find name on old one but was a kit i bought from maplins 3 yr back
amp/cables/ speakers /etc works fine but not a patch on new one [ apart from whine ]
ive tried it with gain turned down and all turned down
all cables are away from each other
nearest they are to each other is coming out radio and going in amp
im now looking at trying it in a family members car
regards.r.r.

 

[redrunner]

hi bhm1712. yes power cables are all away from each other
main feed comes in firewall from battery at front
wireless feed comes from radio up in middle of dash
rear speaker wires up floor side trim to rear speakers
front cross over under carpet nr seats to speakers
but i will look into getting a shield to go over cables and earth it , try anythink
will look on ebay etc
forgot to say when its on and working it sounds great but if you listen you can detect the whine in the background but if i take my hearing aids out its smashing . im passed the blasting it out boom boom age
thing is when its not switched on with or without radio face plugged in ....its whine whine ......
regards. r.r.

 

[redrunner]

I must be getting on a bit.....I've only got my radio tuned into Radio 2 and I haven't used the CD player yet (56 plate Berlingo van)
John

well im just rising on 70 and no surrender regards.r.r.

 

[Burnerman]

1600W and 4 channel
I'd need that just to disguise me tinnitus
John

 

[Peter.N.]

 

[redrunner]

hi, just an update if you still got the will to live
messing with amp today i found i dont need an earth wire to it
its earthing out through any rca cable to radio
which looks like thats me problem
other amp needs the earth wire
next step is to do away with rca cables and use speaker wires to connect to amp see what happens
regards. r.r.

 

[Burnerman]

Cheers for the update!
Curious, that - I would have thought that an earth wire could only really improve things....just shows what I know!
John