unidentified annoying sounds ???

[Cal-a]

hey need help with a sound coming from speakers car is a 88 vl exec i have a pioneer deh-???? wasnt to cheap but when i have the car runnning and the volume turned down a sounds is coming from the speakers and occasionly the sub will go off and start going sounds like a supercharger i guess and gets louder as the revs go up also the noise is there but not as loud when the ac is on.

thing is its crystal clear when you turn the key the other way so the radio itself comes on
i have 2 amps and a sub and 2 pioneer 6x9s

anyhelp would help

[Fonzie]

Electronic interference... Did you run the RCA's to the amps in the same cable tray as the power? They need to be separate.

[Philthy]

Electronic interference... Did you run the RCA's to the amps in the same cable tray as the power? They need to be separate.

^^ What he said. RCAs shouldn't be run down the same side of the car as the power wires.
Failing that, I'd be checking everything to do with your RCAs, making sure its all connected properly, then looking at your earths.

Not sure what you meant about the turning the key the other way thing though

[v8commy]

yeh abrowne70 has the same prob in his vp its ****n weird as hey i dont what it would be def nothing to do with rcas being next to power all my wiring eg power remote rca are all taped together from deck to boot and its ****n clear as that the bigest load of shit ive herd latly and ive said some dumb stuff lately

[Fonzie]

Really v8commy, Really? EFI definitely exists. I made the mistake of running the remote wire with the RCAs and i get faint interference even from that.

Well it's definitely engine related interference, Given that the distortion level changes depending on RPM, that it's crystal clear when it's on accessories (engine off), and the AC being on or off effects it.

Can we have a few more details? From what you wrote... I translated the following (Seriously, try to use punctuation.. it makes helping you a lot easier.):
Playing music is fine, as soon as the frequencies the sub outputs are played, all the speakers distort - Is that correct?

[Philthy]

yeh abrowne70 has the same prob in his vp its ****n weird as hey i dont what it would be def nothing to do with rcas being next to power all my wiring eg power remote rca are all taped together from deck to boot and its ****n clear as that the bigest load of shit ive herd latly and ive said some dumb stuff lately

While I won't argue about you having said dumb stuff lately, I've personally fixed this problem 3 times so far.
Twice in other peoples cars with power wires running down the same side, I could make the whine come and go by holding the power wire a foot away from the RCAs, then sitting them next to each other again.
The 3rd time was in my own car and was simply a case of the RCAs coming a bit loose at a Y-splitter

[holdenboy]

It was common practice many years ago to run power/RCAs seperate. Although with the advancements in RCA shielding its generally not a problem to run them together. It depends on the RCA cable used.

As a rule any interference from the engine / electrical system (which this problem sounds like) can usually be put down to faulty earths, either at the amp or head-unit. I would start by re-doing the earths on the amp, picking a good solid spot (not the parsel shelf or metal part of the back seat) and sand it back to bare metal before screwing / bolting it down.
If that dosent fix the problem it could be the head-unit earth, or the RCA fuse inside the head-unit (common with Pioneers). Re-do the head-unit earth, same as the amps' earth. If that dosent fix the problem then its more than likely the RCA fuse. Not something to muck around with if you dont know alot about electrical components / components inside the head-unit.

[Cal-a]

thanks for your help guys but yeah i went out and had alook at the earths for the amps and they where fine but the head unit one wasnt even conected i havent tried the theary yet as its dark and the neighbours wouldnt apretiat it.

as for the noise when its turned right up you cant hear it as it doesnt get louder when the volume is turned up only when its turned right down.

as for the cable routing i am running an 8 guage wire and a 4 guage wire with the the cables running down the center of the car this is the first time its ever made the noise

do you think that the RC wire might be earthing on the car at the y join becouse thats under the rear seat and may have come loose and be touching the metal under the seat

i will get some pics of my set up and cable routing for you all to see where i might be going wrong

[Philthy]

thanks for your help guys but yeah i went out and had alook at the earths for the amps and they where fine but the head unit one wasnt even conected i havent tried the theary yet as its dark and the neighbours wouldnt apretiat it.

as for the noise when its turned right up you cant hear it as it doesnt get louder when the volume is turned up only when its turned right down.

as for the cable routing i am running an 8 guage wire and a 4 guage wire with the the cables running down the center of the car this is the first time its ever made the noise

do you think that the RC wire might be earthing on the car at the y join becouse thats under the rear seat and may have come loose and be touching the metal under the seat

i will get some pics of my set up and cable routing for you all to see where i might be going wrong

If it has been working previously, and has just started then I'd definately be looking at the RCA connections, especially since you are using Y-splitters

[Fonzie]

If it has been working previously, and has just started then I'd definately be looking at the RCA connections, especially since you are using Y-splitters

Yeah what Philth said is right that it's the first thing you should check (My memory sucks, i can't remember your name and it's only been like 2 days), but i would've thought if an RCA was earthing out you'd be hearing problems right through the volume range.

You said your deck isn't earthed out at all??? That's quite odd. Perhaps it has an earth hooked to the chassis where it's screwed in place too... And it might happen to not be a very good earth for a variety of reasons. Definitely earth out the deck properly.

If the sound is only while the stereo is quiet... it sounds a lot like common interference, but holdenboy knows his stuff so i won't argue (Much ), and if the problem has only just appeared then it won't be this.

[holdenboy]

If the earth on the head-unit is not connected and the head-unit still works fine it is because it will be earthing through the antenna plug. This is not good for the head-unit and could be the source of the problem. Im not saying the RCAs arent at fault, it is possible too....although the head-unit not having an earth may have caused problems for it over a period of time.

[Cal-a]

when i unplug the antena the headunit still works but the noise gets alot louder
and more harsh

[StoneX]

If that dosent fix the problem it could be the head-unit earth, or the RCA fuse inside the head-unit (common with Pioneers). Re-do the head-unit earth, same as the amps' earth. If that dosent fix the problem then its more than likely the RCA fuse. Not something to muck around with if you dont know alot about electrical components / components inside the head-unit.

I can pretty much guarantee(99% sure) it is this.

Take the head unit out and have it checked, there'll be no continuity between RCA outer ring and ground.

[holdenboy]

when i unplug the antena the headunit still works but the noise gets alot louder
and more harsh

Then its earthing through the RCAs, theres no other way for it to be working if the earth wire isnt attached and the antenna isnt either. It will be using the negative part of the RCAs to connect with the chassis of the amplifier i'd imagine.

Yep, the head-units RCA fuse has gone.

[Cal-a]

yeah but why wouldhe noise only be there when the car is running other then that its clear as

if the fuse is gone how do i replace it

[holdenboy]

Because the system is more vulnerable to interference when the car is running.

The RCA earth fuse is inside the head-unit, i havent actually replaced one before but i imagine its a small glass tube-like fuse either soldered into the PCB or held in with clips. You will have to take apart the chassis of the unit to access the internals, then just look around for a fuse like i described above.

Have you tried re-connecting the earth wire?

[azzfox]

He came around today and I checked it with a multimeter and yep, no RCA earth! The noise also went away when we touched a length of wire between the RCA outer ring and the chassis so defiantly blown fuse.

I also have an old pionner head unit here and was curious about what fuses they use. Seems its those small caramel colored things measuring maybe 1x2mm which sits between the RCA earth track and main earth track. Could always do a dodgy and solder a strand of wire between the two.

[StoneX]

The fuses is white and has FUxxx written next to it. The xxx are a number.

[azzfox]

I couldnt spot any of those. Maybe the ancient ones diddnt have any. It has a single sided PCB!

[StoneX]

What model?

They've had fuses for about the last 5 years, before then the ground track would just burn.

[azzfox]

DEH-1550. Nothing to stress about. Its just one of the old units I have laying around with a 99% chance it will never see use again.

But are fuses really necessary? What are they protecting against? Just in case the RCA leads get touched against a power source? Or just static discharge?

[StoneX]

Not sure what they're intended to actually protect from but they were put there because ground tracks were being burnt by something.