well, ive posted this in my caasq rebuild thread but its not getting much attention, anyway, ive just recently installed an alpine cda-9835, love the deck, and the other day i put in my new eclipse xa4000 4 channel amp and ran my front stage active, now when i started the car a was greeted with engine noise!!! ive never had this problem before so i wasnt sure what to do, but as of yesterday and today, ive upgraded the enginebay earths (0awg to copper busbar, 2awg to intake manifold, 2awg to firewall etc) i redid the earth on the amp (better connection to the chassis) and the earth on the head unit, i also re-ran the rcas to the amp away from everything, but im still getting it, i did a bit of swapping around of the rca's and it seemed one of the sets may of been buggered, so i went and bough another set, hooked em up but no..... engine noise is still there :doubt: it only seems to happen when both sets of rca's are plugged in (front/back outputs) if i unplug one set it goes away so im thinking it might be something with the headunit... (bought it second hand off here so no warranty) could any one suggest anything? one more thing, is it possible to use some Y-interconnect from one set of rca's to the 4channel and still be running active? if so ill go get some tomorrow and see if that fixes the problem, i know its not the most appropriate solution but i got no job so if it turns out being the headunits got something wrong with it i cant fork out get it fixed :doubt:
cheers,
tom

you havent got another deck to see if its the pre-outs on the deck?
might be a bit of corrosion on one of the pre-outs
as for those y bits you were talking about you can use them but only if the 4ch amp is running the front speakers, cause it'll save you changing the front setting than the rear to match it, this way it will do it all at once

Yeh you can use Y-bits and hope that get's rid of it, as long as you want the front and rears to sound the same that's cool.
Another thing that can cause engine whine for future referrence is having your gains set too high on the amp.

the amps running my front stage active, so the tweets have their own channels and the woofers have their own channels, all x-over points are controlled by the head unit, that and the amps a dual mono design, so front 2 channels (which are running the tweeters) have their own gain/input settings as do the rear channels, but yes, ill have to try another deck, just gotta finde another alpine to try out now...
cheers,
tom

its gotta be something with the deck... im getting a high pitched ringing noise even when the cars not running... but its only when both sets of rca's are plugged in :doubt: then it gets worse when the cars on, the alternator whine joins in aswell grrr

Is the headunit earth to stock? or to chassis?

Plug an ipod/portable music player into either end of the rca; at headunit and straight into amp? (beware that this is a full range signal going into your tweets so dont play any music)
Is the noise still there? (engine on/off) If its there at the headunit end then its a prob with your rcas or amp.. If its there directly into the amp its likely a prob with amp ground

Best way to test is to pause it and turn up the volume to max on both the ipod and headunit.

Could be rca tracks or poor rca's so dont rule anything out.
Gains may be too high so it is raising your noise floor. (best bet is lots of power and minimal gains)

If its rcas re route your rcas throughthe center of the car where you wont get any induced noise. And work your way through there listening for engine whine all the time.

Engine whines a lot of work sometimes, but its usually something simple, just need to narrow it down.

Let us know how you go

h/u is grounded to stock, but i added another heavier on to another location on the chassis, i doubt its the rca's, the 2 sets im using arnt anymore than 2weeks old, bought a new set today, and they arnt crappy ones, middle range stinger twisted pair etc... amp is brand freakin new, its only been in for about 2 weeks aswell, i had this setup working fine, the when i ran the second set of rca's and went active its started happening but only when both sets are plugged in, gains are up bugger all, woofer gains are up about half way tweets about 1/4 maybe a tiny bit more... im betting on a problem with the rca track in the head unit... ill re-run the rcas down the middle tomorrow ad see how that goes.... also if you could answer my previous question tim, can i run active by using one set of rca's and y splitters at the amp or will this not work? do i need the front rear separation from the head unit?
thx heaps fellas, keep the suggestions coming
tom

there isnt a switch on the amp that says 2ch/4ch
if so then you shouldnt need the RCA's plug into the rear input
you can use those y bits to split the signal from one RCA
it should work as its only sending one signal to the 4 inputs
its worth a shot i picked up a pair of the for 6 bucks when i was installing my second monoblock and they were the only thing i could use to send the same signal to both amps

can i run active by using one set of rca's and y splitters at the amp or will this not work? do i need the front rear separation from the head unit?
If you are after SQ - With your unit you are best off setting it to 3 way, and running the tweets, mids and sub fully active (3 rca runs) with an amp channel for each driver. This will give you the most tuning options in terms of xover slope and cutoff point and will be fully adjustable from the drivers seat. You will see the most benefit out of bass engine pro this way and really be able to get your hands dirty.

By using the splitters you will be restricted to the tuning options on your amp. Whilst you still have flexibility with the xover point, (albeit hard to get to in the boot) The biggest restriction is that you wont be able to adjust the slope of the crossover. Depending on the amp you may be stuck at 12db or 18 db. Depends how serious you wanna go. But I tried out active, passive and semi active/custom passive. They all have their ups and downs. An active setup in the hands of the inexperienced can easily sound shocking. But you learn as you go.

Peace

Tim

oh theres no doubting at the moment (even without engine noise) it sounds terrible... but i dont have my sub or my new tweets yet.... so im not even bothering with tuning at the moment... just trying to iron out the wiring and intsall side of things at the moment, its just so annoying something so mediocre can halt progress.... this is such a stupid problem to have haha i didnt even get it when i had every cable bar the right hand side speaker wires running down the passenger side lol, the head units on 3way active at the moment, just waiting on my IDMAX to arrive, but then i gotta build a box for it.... as for how far i wanna go... well, ill onlly be starting in amatuer street.... but knowing me ill want more and more and end up in pro show or something silly haha

...im betting on a problem with the rca track in the head unit... ill re-run the rcas down the middle tomorrow ad see how that goes....
tom

did that sort out your issues with engine noise tom? I've got a problem with engine interference too and i'll have to spend a bit of time playing with the system.

good luck with your probs

pete

havnt done it yet... went out and played around with it a bit more but was just giving me the ****s so i went inside and watched tv lol

re-ran them down the middle today and the engine noise is pretty much all gone! still a little amount of engine noise wheich ill ignore for now but will have to be gone if i want to enter any caasq comps :doubt:

Good stuff!

sounds the goods, i'll have to give it a shot when i've got some time on my hands

I'd say its an Earth somewhere...

Probably in the deck RCA's. We had a VY Clubbie in3 times and rewired it, new decks, amps, wires, Untill we got the noise down... but not gone. It didnt matter what we did to the car it had engine noise. Especially with the Air con or thermo fans on. Nothing we did fixed it but turning the gains down on the amp definately improved it to almost gone

Problem solved already, it was and usually is simple... low level signal wires such as RCAs running parrallel to DC power wires induce interference.

Always run your rcas away from power wires if they have to cross, cross them perpendicular. Also keep them away from stock electrics

Peace

Tim

mine are on the other side of the car and dont cross. and have alternator noise. but the alternator is on its way out so prob that.