heyo,

I've got the good old alternator whine happening as you'd expect from a magna!

I've searched this topic heaps and found lots of good stuff.

I've checked my amps grounds with a multimeter and they're good.

I've plugged in my ipod to the amps directly, and no noise with the car running. Thus amps aren't the problem.

My power cables run down the left hand side wiring tunnels of the car, into the amps which are under both front seats. So, the amp under the drivers seat has about a metre of cable running under the centre console to get to the 2nd amp. This amp is however in repair, and the fuse it out at the distro end of things, so shouldn't be an issue.

My head unit is pretty crap and needs replacing, which I'll do in time. It's a pioneer one, and only has 1 rca pre-out which I'd assume to be NOT 5V. What I have been doing is having the RCA come out of the H/U and down the centre console, going out to the right into the 4x100wrms, which has a pass-thru RCA out. The pass-thru sends the RCA back under the centre arm rest and back to the 2x150wrms under the passenger seat. This set up never had anything more than a VERY minimal whine that you could barely notice. Even before the 4x100 amp blew up it had no problem with the new speakers.

Technically, the RCA under the console shouldn't be inducing noise because there's no power going through the power cable that's near it.

Obviously I turn to earths next. I need to earth my H/U better I think. It's on factory earth now, which is never satisfactory. What's the concensus on the best place to earth this sucker?

How do you upgrade your battery and alternator earths? Theory wise, no problems, but I'm about as practical as a one legged man in an ass kicking competition when it comes to frustrating, dirty, greasy things under a bonnet. I can't even SEE where the fricking earth goes from the battery. On the schematic it declares that there's 2 separate earth points from the battery. I can only imagine it's somewhere under the battery. The transaxle is down there, so it must be right up near the wheel arch. Again, where have you guys done this? Hints?

The alternator.... it's right down the bottom of the bonnet space. YAAAAAY. Not. I really don't relish the thought of playing around from the top on that one. But how do you go about upgrading it's earth? Just check that everything is connected right and not loose? And sand back the chassis it's mounted to? Is that the strength of it? If you went to thicker earth cables, then you'd have to start them from the original terminals wouldn't you? There's no point attaching 2ga to an 8ga, because any benefit the 2ga might have would be snuffed out by the 8ga original cable?

Same for engine block... it earths to firewall doesn't it? Where? Is it that little earth point up quite high on the firewall in the middle behind the throttle body and plenum? 2nd gen here guys btw.

Also, I don't want to do this if I can get away with it, but those 40amp filters... where's the best spot? I don't want to put it's pus-box 8ga wires in between my battery and my main 4ga run. I've got 8ga runs out from my distro block, but if I whack it on one of those, then it's only going to filter one amp. I can see sense in this as the sub doesn't play alternator or motor frequencies anyway. But as I said, I really don't want to do the bandaid thing. I would do it in the meantime before buying a new H/U if I couldn't do anything else.

It just seems strange that I never had a problem with it before, and now with the new speakers it's a real good strong noise. They're running off the 2x150wrms amp. There was no noise when they were on the 4x100wrms. It's weird!

RCA's I reckon

Reroute them, you dont need to worry about only the audio power, its also the car power, and there is a heap of crap behind the dash.

Try reducing your gains a bit that way your headunit will put out more voltage for the same db's, and will drop your noise floor.

Also try checking the grounds at your battery to make sure they are clean and tighten up your grounds everywhere else. (headunit)

With the car stereo running move the line level leads (RCA's) around the top part of the console (under your stereo area). There is a lot of noise generated from electronics into the RCA cables right there. I had the same problem and this fixed it.

What I usually do is have the system playing a song or maybe a single tone.

And start playing around with all the wires, connections.

When you hit one that removes/induces noise into the system then youve found the culprit.

If none make a difference then you could start looking at other reasons.

ok... I'll go have a play with the rca's. It certainly makes the most sense. Might put the h/u ground on chassis if it shows up dodgy on the multimeter. Thanks guys.

hmm.... I have pulled out the RCA run and moved it away from everything... no difference at all. Moved it to try and find more or less inducted noise, but nope... all stays the same.

I've got the dash apart now and one seat out, so I might as well take out the whole kit and caboodle and hope I don't need to go anywhere tomorrow.

The head unit earth looks good. I really don't know what's the cause of this one! I'll check the grounds on the other amp again, but it's showing a pretty darn good earth on the multimeter. I might change my RCA route, but it didn't seem to make much difference, so maybe that's pointless. :S

any tips on battery, block and alternator grounding fellas?

Replace the whole wire on the alternator to as big as you can. Also add extra grounds around your engine bay to the negative terminal of your battery.

RCA's are the biggest culprit for induced noise in the system, not power wiring. Be it bad shielding of a slightly loose conection to your preouts or the amp, it will 95% of the time be the problem.

Try pulling out your RCAs from the amp while the system is on, but not pumping. You might get an audible pop as the signal drops out. If the noise goes away, it's the RCAs, as if it was coming through the power wiring, the power is still connected and the amp is running, it would still be present without any RCA input. You'd be talking about a ground loop or something similar if you unplugged your RCAs and still had the noise.

Most of the time, the only course of action is to replace the RCAs with new ones. Try and buy quality items, I have just replaced my 4x75W amp with a 4 channel Stinger Hyper RCA cable (1 cable does all 4 channels) and the subs with 2 channel Stinger Helix (triple shielded) cable. You could test it with a cheap 5m cable from Tandy or Strathfield or dick smith. If your cable is damaged, you will hear the difference straight away. Alot of people have a 5 metre RCA cable floating around the house somewhere.

You are looking at about $50 for the 4-way cable. Try and buy the best you can with the most shielding.

If then, and only then, you still have the problem, look at filters.

yeah, I know it's rca noise. I have only got jaycar ones... the twisted pair shielded ones. They've been good up until now, but I might have to go get the stinger ones. I will upgrade the earths too though, I'm sure they're not all they could be. Yes, I'm very loathe to use a filter. I want a new head-unit with 5v preouts too...

I'll let you know if anything weird happens anyway. I'm sure it's just the regular stuff. But if not, I'll be tellin ya! :)

ARGH!!!!!! This is SOOOOOOOOO annoying!


I Scratched and sanded back my amps grounds to bare metal and made sure they were tight as a fishes bum. No difference.

I unplugged the aerial... no difference.

I got stinger helix rcas, no difference, not even marginal difference.

I've decided it's not induced noise. I'm pretty certain it's a ground loop.

My battery grounds are clean and tight. They should be good. Same goes for alternator. I really don't want to stuff with that yet. I HAVE got a 4ga earth wire that I'll put on the alternator if I really have to. Would I be better upgrading the earth on the battery or the alternator?

Right now I'm off to redo my head unit ground, which I hold out the most hope for. I just wanted to vent my frustration! :)

I want a new head unit too. But I have to wait about 6 months for that. 6.5v preouts will be nicer!

Also, my car is getting serviced soon, and the plugs and leads are getting pretty shady... I've read that this can cause ignition noise, which I'm getting a bucket load of also. I'm hopeing that once I get the plugs, leads and dizzy/coil looked at that this might go away. That's not going to cause alternator whine though is it?

Anyway... back to the garage. grrr.

lol touch wood I have never had this problem.... thank god.

What are the gains set to on your amp?

This might sound strangle but have you tried your speakers off another amp or even the headunits amp to see if there is noise in there? It may be the amp its self. See which amps are making the noise before doing all the grounds as that will be un-necessary. I have a Pioneer with 2.2V preouts and have not worries, volume goes to 52/62 and gains are set right for less ground noise, maybe you should try that :D

Yeh what volume is your headunit on when you get ur engine noise?

eg 20/50?

you want to make sure you as much of your pre out headroom before clipping. Even on my system I get a lot of noise if I turn my gains up. So I have them all on minimum, and use other components to bump up the signal voltage.

Peace

Tim

I get noise at any h/u volume, and any amp gain... I will double check the amp gain again, but pretty sure.

I know it's not the amp, coz it plays fine when the engine isn't on. It's just when the fans and ignition comes online.

I've also plugged in my ipod directly to the amp, and no probs... so it points at the H/U in my mind.

Going to check the gains, might be worth a shot....

and then I'm going to pull out the h/u and and see if it's the chassis of it making a loop with the car chassis.

It's a really pain in the bum! :D

It's not speakers, not amp, not rcas, not gounding on any components.... it's pretty crazy!

I'll keep playing.. my dad has started to get intrigued by it now... lol he's an electronics technician who used to fix radios, build amps and installed the radar at brisbane airport (not the currect one). When they first turned it on, it picked up birds and even smaller insects on stradbroke island. Pretty funny! That's also the radar that deteced the B2 bomber when it overflew brisbane, in full stealth mode.

anyway... back to work!

I have a feeling fhrx is laughing at me quietly... I don't know why, but I just wish I could have spent 7 grand and driven down to get him to install the system I originally wanted. :(
But... it's JUST a car, and it's JUST a stereo... *sigh*

ah have you tested the amp with the engine running?

edit: HAve a look at this chart too... Good for finding noise issues...

it could be the headunit earthing against the chassis, (try grommets) Worst case it could be fried RCA tracks,

DONT PLUG IN RCA LEADS WHEN EQUIPMENT IS ON!!! Can fry ur tracks easily

yeah, tested it running....


woah, that's weird!!! I turned the amp gains to 0, and turned the car acc on (with the fans and ignition).

I would have thought the head unit should be able to play up pretty high on it's volume range without the sound getting too loud? My head unit goes up to 62 I think... I can't get past 50 before the volume is rather loud, and the speakers are making little popping noises... not clipping as such, but overdriving the speakers type of pop.

I used to be able to turn my H/U up to 60 with no distortion, and 62 with just the smallest bit of clipping... I think it goes up to 62 anyway... I'll check... just have to unplug rcas from amp. hold on....

yep, 62.


I also just found a rather disturbing thing... when you touch the chassis of the amp itself, it makes the speakers pop....... that ain't right.......... wtf!!!

I'm getting real sick of this.


Dad seems to think that the amp might have a transistor leg loose on it's preamp stage somewhere that causes the pop when you bump the amp.

I give up... even tried the filter and no difference. Would possibly help if I had better head unit, but I'm sick of spending money on guesses. Going to wait for my 2nd amp to come back from repair, service my car and then put it all in and take it to somewhere and get them to fix the noise. I'm stumped. It's not even a complex system. :(

AHA!!!!!!!!!!!!! I found out something... not about my noise probs, but about jaycar amps!!!!!!

They are pretty cheap and crappily built... and the lid has about a mil or 2 clearance from the top of a cap. It shorts if you push the lid against it. That's what that noise was... took the lid off and it stopped. Looked at the lid and you can see little black spark marks, right over the caps. Tap the caps and you get the noise!!!!! LOVELY piece of engineering!!! lol So I'm putting some hard plastic over it for now.

But that means it wasn't my speakers that stuffed up the other amp, I would nearly put my life on that now. If it was my speakers, it would have blown that fuse on the amp and gone into protection... but it didn't... it only blew it's power fuse, and there's NOTHING wrong with it's power wire.

Point of story? Don't trust Jaycar stuff. Buy it... but DO NOT trust it. It's cheap, and good sound quality and power for the price, but it's pretty shockingly made!!!

No luck with the yucky noise though. Will wait til everything is back in and see how we go again. The stupid thing is, when both amps were in and all the speakers, it had no noise whatsoever for a few hours, then it blew the amp, and now with the speakers on the sub amp, it's got horrible noise. Weird hey!

Did you know that shielded audio cables actually induce more noise than UTP cables?


oh by the way tim..... how would I check the rca tracks easily? I kinda suspect them, although they work clean enough without the engine on....

A bad case of you get what you pay for unfortunately :p

;)

Checking rca tracks, unless ur a techy you prob shouldnt open up your headunit. There's probably an easy way, try checking for resistance b/w the headunit chassis and the rca from the outside (just a guess, Im not too sure how to check short of opening the thing up and voiding warranty). I wouldnt worry too much about it now as it sounds like you've found ur problem.

Peace

Tim

AHA!!!!!!!!!!!!! I found out something... not about my noise probs, but about jaycar amps!!!!!!

They are pretty cheap and crappily built... and the lid has about a mil or 2 clearance from the top of a cap. It shorts if you push the lid against it. That's what that noise was... took the lid off and it stopped. Looked at the lid and you can see little black spark marks, right over the caps. Tap the caps and you get the noise!!!!! LOVELY piece of engineering!!! lol So I'm putting some hard plastic over it for now.

But that means it wasn't my speakers that stuffed up the other amp, I would nearly put my life on that now. If it was my speakers, it would have blown that fuse on the amp and gone into protection... but it didn't... it only blew it's power fuse, and there's NOTHING wrong with it's power wire.

Point of story? Don't trust Jaycar stuff. Buy it... but DO NOT trust it. It's cheap, and good sound quality and power for the price, but it's pretty shockingly made!!!

No luck with the yucky noise though. Will wait til everything is back in and see how we go again. The stupid thing is, when both amps were in and all the speakers, it had no noise whatsoever for a few hours, then it blew the amp, and now with the speakers on the sub amp, it's got horrible noise. Weird hey!

Did you know that shielded audio cables actually induce more noise than UTP cables?


oh by the way tim..... how would I check the rca tracks easily? I kinda suspect them, although they work clean enough without the engine on....

money spent on jaycar amps in last 3 weeks - $509
finding out you shouldnt of bought them, only a week after you did - priceless

lol I know of boss amps that do that... we will take jaycar and but it there...

Seriously your one is the first one that has done that from what I hear, do you have the new ones or the old one? I have the old one in my bro's car.. no problems.

yes... I KNOW it's a case of you get what you pay for... I was well and truly prepared for that... so there's no red faces and pricelessness... it's not like I'm suprised. :)

The amp that fried was the new 4x100..... but the amp that I figured out the problem is the old black 2x150...

the stuff is still worth what it costs... I'd still get it if you're on a tight budget... well and truly better than sony, boss, or other stuff in similar price ranges. I think you just have to be a bit more clever and less trustful of it's build quality. Thankfully, those kinds of things can be fixed with some thin hard plastic and super glue (they should put a note in the box saying that to keep the cost down you should do some final finishing of the amps yourself lol ). The terminal blocks are also another weak point on them. But all in all, I've been happy with them. I'd rather learn things on stuff that doesn't matter all that much. I'm really happy to have no blown up a zapco reference amp accidentally and fried a nakamichi deck with top of the line morels and rainbows and a xxx sub. I would be crying quite literally then.

I just hated the fact that my magna had no speakers in the doors, and wanted some half decent quality tunes. I've got that, and even though there's been this one nasty bit, that's the only one. I won't hold it against them. :) And I guess I'll keep lusting after the high end stuff... but seriously, I can't justify the spend.

That's my 2 cents anyway!

Thanks by the way for all your collective help and suggestions...

and I hope that you can all have a chuckle at the expense of jaycar! :D I know I have. Apart from the 1 point where I got frustrated with it that is.... lol

I love this forum! So much crap goes on........ and yet somehow, it's all good! ;)

I have a feeling fhrx is laughing at me quietly...

No champ, that is not I operate. We all have to start somewhere. :)

yeah, I know dude... lol I was just wishing I could have come see ya for it. Wanna move to brisbane any time soon? :D