Audio whining interferance

[brady5885]

Just fitted my sub , 6x9s and wired up my door speakers to my amp.

Now i know u need to seperate audio and power cables so i have power down the left and my rca's and door speaker feeds down the right.

I have a whining interferance off the alternator, it changes pitch when i rev it and is really loud when i turn the gain up a little.... anyone got ideas why its doin it??

 

[tomtaffa]

Is ur head unit a pioneer??

 

[wallop]

Not enough info supplied to allow for an accurate diagnosis....

A post copied from another thread I did regarding your issue....

Background noise/Alternator whine....

To sort this you need to actually locate the source of the noise....

Is the noise only present with the engine running....

YES---Then its going to be a ground loop scenario, in 90% of cases its poor amplifier earthing thats the root cause....

Amplifiers should be earthed to the boot floor using good quality connectors, the earth site should be cleaned back to bare metal and once tightened treated against corrosion....

NO---Then chances are its down to a faulty item.....

With system switched OFF....

Remove the RCA leads from the affected amplifier....

Switch system on and play as normal....is the noise still present??

YES---Then its an amplifier or associated wiring fault, (Speaker cable pinched & shorting?? Speaker terminal shorting to a door panel?? etc etc)

NO---Then the fault is before the amplification stage, carry on...

With system switched OFF...

Refit the RCA leads into the amp, remove the head unit from the dash and remove the RCA leads from the back of it....

Switch system on and play as normal....is the noise still present??

YES---Then its a faulty RCA lead, simply replace the affected lead.....

NO---This would indicate you are probably using a PIONEER head unit which at some point has been connected up or disconnected incorrectly which has caused an earth track fault,(it can affect other brands, but the main culprit is PIONEER)...


To get round this fault,(it's not a repair, it's simply a quick fix), you should do the following;

Run a fused direct live,(20amp cable fused at 15amps), from the battery to the head unit,(essentially bypassing the audio looms constant live). you should leave in place the ign live so the unit operates as it should on the ign...

Run the head units earth,(again bypassing the stock audio loom), direct to the cars chassis,(use 20amp cable & ensure you select a good earth site and clean the area back to bare metal), the condition of this earth site will affect the success of this quick fix...

You will now need to earth the RCA plugs outer sleeves to the head units chassis,(i usually use the head units rear support screw location), this fix should solve most cases, but on occasion it can be necasary to also earth the head units mounting cage to the cars chassis....

 

[brady5885]

yeah it is a pioneer headunit, will try another sub earthing point then if that doesnt work looks like it will be a by-pass of the loom...

will one of those ground earthing suppressors work??

 

[tomtaffa]

well iv got a pioneer head unit and apparently there known for the earth in the head unit goes, if it's less than a year old i think you can send it off and get it fixed for free, mine did the same thing still hav'nt got it sorted.

 

[Paddy_g46]

I have a pioneer with the same sort of problem, no amps or anything, and the noise gets worse with revs! How can i fix this myself?

 

[tomtaffa]

well i hav'nt done it myself but the lad who told me about the problem said to send it off as to resolder it is realy hard because it's only 1mm wire or summet but i suppose if you get an iron with a sharp enough tip you could open it up and try it yourself!

 

[brady5885]

well i hav'nt done it myself but the lad who told me about the problem said to send it off as to resolder it is realy hard because it's only 1mm wire or summet but i suppose if you get an iron with a sharp enough tip you could open it up and try it yourself!

which wire where? ones goin into the unit to power it? theres no id's on some of my cables so i dunno which to wire to a fresh earth

 

[tomtaffa]

nono actually inside the unit, apperently you shud just be able to see the solder that has broken and thats obviously the fault, but i just havnt had the time to get round to doing it tbh

 

[brady5885]

is this an alternative to the solution at the bottoms of wallops post? or could this also need doing? i have an avic x1r dvd/sat nat unit fitted

 

[brady5885]

also i never had a problem thru standard door speakers when i was just runnin a sub with standard speakers, only happenin now ive fitted new sub amp and hooked 6x9's and my door speakers to the amp

 

[tomtaffa]

mine was the same could just be a bad earth to your car, where is yours earthed to?

 

[wallop]

With regards 'Pioneer' earth track issues....

The earth track in these units actually has, what is best described as, a type of fuse within the unit that during normal operation is absolutely fine....Problems arise when items are either added or removed in the incorrect order....This causes, or rather allows, external units to earth via the actual Head Unit itself....

So, warranty claims for this fault are occasionally refused if they occur upon initial installation of the unit....As the unit ages the chances of this fault being rectified under warranty greatly reduce....

As stated this isn't a fault as such, it's basic owner misuse....

I have done a more detailed post somewhere regarding the quick fix mentioned above.....

Will go search for it now.....

 

[agithegreat]

Basically the fix is make the RCA earth = gnd. It can be done even without removing the case of the HU. Spin a bare wire around all the RCA's then connect to earth. Simple. That's identical to what the fix is on TA which i believe wallop posted about some time ago.

Technically it's not a great fix as it removes floating RCA's (which apparently add to SQ). So put down the pitchforks as i know some of you will be raising them at that post!

 

[wallop]

Thats the one mate....

As stated, bare enough copper wire to wrap round each pre-out on the rear of the head unit, (use the RCA plugs to hold in place), then simply connect the other bare end to the head units chassis....simples....

 

[brady5885]

Run a fused direct live,(20amp cable fused at 15amps), from the battery to the head unit,(essentially bypassing the audio looms constant live). you should leave in place the ign live so the unit operates as it should on the ign...

^^^^
should this need doing as i thought it was a grounding issue?? could new earth for HU and rca's not do it

 

[sideways danny]

I always run a separate earth from the headunit case to the body. I've had this before and it helps. Also had issues with poor earth points to the amp

 

[agithegreat]

It is due to a poor earth onto the HU which ultimatly causes his fault.

The HU has too high a resistance to earh, so uses the RCA shield (essentially an earth for the rca's) as it's earth, which is why the resistor inside which is to stop this happening blows, as such the amplifier is then totally reliant upon using it's earth point as a centre line of which the now fully floating RCA's work across. So simply were using the earth as the RCA shield now. So no floating RCA's.

In answer to your question about the dedicated live and earth yes ideally it should.
You may well find however that the loom for the clio is adequate enough to cope with pretty much any HU.

The best possible thing you can do is to wrap the RCA's to earth as above, then use the earth point on the HU and run a dedicated cable straight to the amps earth.

 

[wallop]

Run a fused direct live,(20amp cable fused at 15amps), from the battery to the head unit,(essentially bypassing the audio looms constant live). you should leave in place the ign live so the unit operates as it should on the ign...

^^^^
should this need doing as i thought it was a grounding issue?? could new earth for HU and rca's not do it

You must first locate the source of your interference by doing the above tests....

If it is indeed the earth track which has blown, then the earthing of the Pre-Outs to the Head Unit chassis will solve your issue....

With regards the introduction of a dedicated fused power supply; The stock audio loom within your car was designed with only two parameters, safety & cost....By fitting an upgraded Head Unit you push these parameters yet further....

Where is the logic in spending money on external amplification & better speakers if your happy to strangle the actual source unit by relying on wiring which, whilst safe, pays no heed to performance....

As an example; Open your door so the interior light is on, operate almost any electrical circuit & the light will dim, switch the 'Hazard' lights on & it will dim in time to them....This occurs because the entire loom within your car was designed & built with safety & cost as its main concern....

Any dip in voltage experienced by your Head Unit will obviously affect Pre-Out voltage....

Seem to be rattling on again....Sorry....

 

[wallop]

It is due to a poor earth onto the HU which ultimatly causes his fault.

The HU has too high a resistance to earh, so uses the RCA shield (essentially an earth for the rca's) as it's earth, which is why the resistor inside which is to stop this happening blows, as such the amplifier is then totally reliant upon using it's earth point as a centre line of which the now fully floating RCA's work across. So simply were using the earth as the RCA shield now. So no floating RCA's.

In answer to your question about the dedicated live and earth yes ideally it should.
You may well find however that the loom for the clio is adequate enough to cope with pretty much any HU.

The best possible thing you can do is to wrap the RCA's to earth as above, then use the earth point on the HU and run a dedicated cable straight to the amps earth.

Interesting reading mate....And so much shorter than my post lol....

Just one thing to add, (being as we seem to be explaining how the earth track blows)....

In my experience the main cause for any Head Units earth track to blow is incorrect wiring sequences closely followed by poor amplifier earthing practices....

A poorly earthed amplifier will tend to earth via the RCA leads through the Head Unit so overloading the earth track....

An amplifier which is connected or disconnected in the wrong sequence will also result in the amplifier earthing in the above manner....

Here is a copied post I did on another forum with regards wiring sequences.....


CAUTION; When working on a system you should pay heed to a few safety tips to avoid possible system damage;

If any part of the boot power supply is to be disconnected, (Earth or Live), then always follow these easy steps to avoid possible head unit damage).....

1, With system switched off....
2, Disconnect all RCA leads from any amplifier which is/has been in use....
3, Reconnect all RCA leads last....
4, When fitting any amplifier you should ensure you wire it up in the correct order;

Connection sequence;
1, Speaker wires
2, Batt +ve feed
3, Amplifier earth
4, remote turn on
5, Double check all connections, fit power supply fuse, Switch system on and check amp powers up.....
6, If amp powers up OK, then switch system OFF....
7, Connect all RCA leads....

To disconnect an amp;
1, System OFF...
2, Remove RCA leads, remove power supply fuse....
3, Remove amp remote
4, Remove amp earth
5, Remove amps batt +ve
6, Remove speaker wires

Simple Rule---RCA leads should be connected last & disconnected first....

 

[brady5885]

^^^^
Great reads guys, will hopefully sort it at the weekend and let u know the outcome

 

[tomtaffa]

wish i could understand all of this cos then i could sort mine at the weekend too looks like il be paying my brothers mate to sort haha