Stereo interference...nearly there...just need last bit of HELP!!!!!!!

[Piggy]

ok...so I thought I had a duff amp.

Amp was a cheap unknown brand and my second hand but like new Pioneer headunit was like new. And the best headunit I have owned or bought.

Turns out to be headunit...but I am hoping someone can shed some light on fixing the issues/headunit.

Basically with amp phonos plugged in to headunit, one for sub, one for shelf speakers, with volume on 0 and ignition on, there is a high pitch buzzing from speakers and low pitch grumble from the sub.
Engine on and this becomes a VERY loud buzzing from both.

With just ignition on, if you operate fans or indicators or wipers, you hear them operate via the speakers...if that makes sense.

I assumed amp was gone...so got another. same problem
I tried new earths on both amp and headunit, new phonos etc...

then plugged in an old tatty slightly buggered headunit...and nothing. No buzzing at all.

I am gutted

any suggestions?? the model of headunit is Pioneer DEH-P70BT

I have ordered one of each of these to try:

http://www.ebay.co.uk/itm/200980627669?s...1439.l2649
http://www.ebay.co.uk/itm/140500004951?s...1439.l2649

but I have a feeling they are just not guna do it

[MarkTD]

Have you checked the RCA cable(s)?

Could be interference from wires touching or you could have a slight break in a line in any of the wires that the new unit would pick up because of it being better quality.

[Piggy]

as said, tried diff phono cables.

Turns out the issue is still there...

when engine is running, even with different head unit, it still whistle/buzzes in pitch with engine revving

[Jimbo]

Running the power lead and rcas down diff sides of the car so they dont interfere?

[Piggy]

Hmmm...be surprised if that was the issue...both are high spec insulated leads...but its not a bad shout

[devils_fuel]

Have you fitted the stereo suppressor yet as the issue maybe that the HU needs suppressing, std/crappy stereos don't usually need/already suppressed.

Have you checked the power lead from the battery to amp etc, the better HU may pick this up or dodgy connection where as the crappy ones isn't sense active enough ?

[Piggy]

Have you fitted the stereo suppressor yet as the issue maybe that the HU needs suppressing, std/crappy stereos don't usually need/already suppressed.

Have you checked the power lead from the battery to amp etc, the better HU may pick this up or dodgy connection where as the crappy ones isn't sense active enough ?

suppressor!?

what is this and where does it go and what does it do!??

its gota be power/earth somewhere jazzing out.

[devils_fuel]

Your top eBay link . Does the buzz get faster(sometimes louder) the faster the engine speed?

[Piggy]

Your top eBay link . Does the buzz get faster(sometimes louder) the faster the engine speed?

ah...ordered today. so not fitted yet!!!

yeah its connected to engine speed when engine running...

or when just ignition on, it can relate to fans, or indicators or wipers.

[devils_fuel]

Sounds like interference on battery draw/alternator use, that top link may solve it. Ages ago my mum had the similar issue in a car, just a HU swap and a suppressor stopped it

[pugvivant]

Used to have same issue in an old beemer 325. Which had a alpine, was alternator noise coming through, you could hear when the gears changed and got pitchy with speed.
In line suppressor cured it

[Piggy]

cool thanks chaps...

soon see

[Dean]

That does happen when you run power cables and the phono leads next to each other. Found that out on my 106.

[WiNgNuTz]

I always make sure to run the power down one side of the car, then the RCA and remote down the other.

[Piggy]

ok cheers guys.

bummer though as the main power cables run down the centre of the car....bit stuck as I cant move them...

[devils_fuel]

I always make sure to run the power down one side of the car, then the RCA and remote down the other.

My cables are touching each other, I run alpine HU to alpine amp and no interference

Fitted the inline suppressor yet piglet??

[WiNgNuTz]

I always make sure to run the power down one side of the car, then the RCA and remote down the other.

My cables are touching each other, I run alpine HU to alpine amp and no interference

Fitted the inline suppressor piglet yet?

Fair enough, its kind of a personal preference on my behalf....so nerr.

[Piggy]

yeah but I got two main battery cables running almost next to rca cables...
or I did till I changed that today.
then got cold.
got a suppressor for the alternator...will fit that asap then plug in the HU and try again

[devils_fuel]

yeah but I got two main battery cables running almost next to rca cables...
or I did till I changed that today.
then got cold.
got a suppressor for the alternator...will fit that asap then plug in the HU and try again

I guess you may have pulsing interference with 2 mine lives next to the RCA's. Have you fitted the suppressor, any joy?

---

I always make sure to run the power down one side of the car, then the RCA and remote down the other.

My cables are touching each other, I run alpine HU to alpine amp and no interference

Fitted the inline suppressor piglet yet?

Fair enough, its kind of a personal preference on my behalf....so nerr.

I quickly wired in the ICE and due to no issues never revisited it lol, should really move them to each side of the car

[Piggy]

guns try alternator suppressor tomorrow if can get me wheels sorted

[Piggy]

grrrrrrr

alternator suppressor and ground loop isolator in, also redone battery earths, loom earths and amp earth.

AND NO CHANGE!

tried both amps and headunits and its all the same.

you dont get it through the normal output, only from the preout/amped speakers/sub

[devils_fuel]

Do you have a good short earth?

[Piggy]

about 10inches.

is was direct to battery as have battery in boot floor...

but its now going straight to a freshly made earth point.

[Piggy]

so plugged my phone in direct to amp.
no hiss/fuzz/tick or anysort of interference.

so plugged my phone straight into RCA cables at HU end...

same, no interference.

next I provided the headunit with its own power source...
still have interference.
did same with amp.
same thing.

next and final thing is to relocate batterg back into engine bay and see what, if any, difference it makes.

doing my friggin nut in

[Tom]

I bet it'll be fine with battery up front. Probably to do with the alternators power travelling the length of the vehicle.

[jamie23]

shouldnt make a difference where the battery is my beemer had it in the boot and worked fine sounds like the phonos on your head unit are fooked to me but i could be wrong

[Piggy]

guna try giving phonos a direct earth

[devils_fuel]

Can you/get someone to replace your RCA plugs on your headunit?

[Piggy]

maybe. but the expense of that probably isnt worth it.

I had it nearly all apart to see how the board worked but my mini phillips is missing so only went so far....will try earthing rca outputs to HU body and makin a independent HU earth too and see what happens

[Piggy]

OK.
SO earthed the Headunit directly to the chassis right underneath it (its sitting in lower console not in main dash) and also earthed the RCA audio cables to the body of the headunit...with a inline 3amp fuse.

This has cured the alternator whine, low rumbling and high pitched hiss.

It has NEARLY cured the heavy tick/pops and whines which copy any accesories I use...like indicators/wipers/fan/lights etc

BUT NOT QUITE>

still a little pop when something turns on then off, like an indicator or lights.

ANY IDEAS????? Im close to hammer through the windscreen stage