High Line Amplifier, with new Stereo head unit

Hi All,

After an almighty faff, i have managed to fit a pioneer stereo into my 2004 landmark discovery 2. Its one of those stereo's with the flip out screen and built in bluetooth. im dead please with it, my landy now has built in sat nav, hands free calling (via bluetooth), the ability to play DVD's and an ipod connection. I have even managed to keep my steering wheel controls working.

However....

As soon as i turn the ignition key to the first position the stereo powers up. this is fine and this is what it is meant to do however even with the stereo source set to off i have a faint hissing noise. the only way to stop the noise is to remove the stereo security faceplate.

when i play music / a dvd / the radio (any noise) it sounds great and you can no longer hear the hissing noise. the hiss doesn't get any louder with the stereo volume nor is it related to the engine running / revving as i have read on other parts of the forum.

I have titled this thread 'High line amplifier' as i am wondering whether this hiss is amplified nothingness. The volume on my new pioneer is incredibly loud (at 4 you are well on to becoming deaf and at 5, the whole neighbourhood is involved). Any thoughts? I was wondering whether i could simply connect the incoming amp wires to the out going amp wires, thus bypassing the land rover amp altogether (ie just using the pioneer head unit).

i have also read about poor ground loops and that a solution could be connecting my black ground circuit to a new grounding point on the vehicle (one that i make by finding bear metal and connecting my ground circuit directly too).

any help would be greatly appreciated, like i say i am head pleased with what i have achieved, but the hours ive already invested, i really want it to right!

kind regards,

James

Is it like white noise? Could be a wire picking up a frequency and amplifying though speakers? or a problem with head unit

I'm no expert but I suspect the LR main amp expects a lower level input from the pre-amp rather than the speaker connections of your new stereo. So your plan of connecting to the output of the LR amp sounds good unless there is a pre-amp output from your new bit of kit.

Earth loop problems generally give a low pitched hum (and ISTR are usually only on mains equipment).

As above, adjust the head units output gain to you amp a bit lower than it's at now, the Pioneer handbook/manual will tell you how.

I have the same problem but I think the hissing only seems to be coming from the rear doors so it definitely todo with the amp so I'm looking to change the the amp and check the wireing but I'm not sure what amp to buy at moment

hi guys thank-you for all your advice, i'll have a play today an report back.

the head unit is a pioneer avh-5200bt

kind regards

james

hi guys, still haven't managed to fix this noise; however recently i have discovered that the a-pillar tweeters? (speakers) are making the noise and that the noise increases when i rev the engine.

a google search and the results suggest i have a ground loop. this makes senses having looked through the rave manuals. the high line amp (under the passenger seat) is earthed at a different point to the stereo head unit.

according the earthing point location diagram;

Head unit C0361-1
Amp C0708

however this is where my confusion arises. C0361-1 is what i would consider to be an earthing point. its a bolt in the metal work of the car. this aligns with all the advice on ground loop problems that says attach a new earth to bare metal etc etc.

C0708 looks like some type of plug / connector. admittedly i haven't had a look yet. i've only been looking at the pictures in the electrical library but does this make sense to anyone?

im asking because i was thinking about making a connection between these two earthing points. the theory being - im connecting the pioneer head unit (which i think has its own amp in it) to the land rover high line amp, thus they have the same grounding point, and therefore no ground loop?

before doing this though i'm looking for some reassurance. also the amp earthing point apparently is within the center console, which i am really unsure how to get at. alternatively, could i just splice into the earth wire from the amp, therefore negating the need to find the amp earthing point?

all the best

James

reporting back...

i managed to fix the ground loop. i ended up finding what i thought was the stereo earth point (behind the glove box) and connected 2 wires to it (soldering on eyelets). i then spliced these cables into the two black cables going from / to the amp. this meant that i didn't have to find where the amp earthing point actually was.

result, no change in background noise when i rev the engine.

i still have a white noise though. i am begining to think it could be a stereo / amp gain issue as mentioned on this forum (i have no other ideas at this point), however i have absolutely no idea how to tackle this one....

nothing in pioneer manual

the internet mentions putting a resistor between the two devices, but there is sooo many cables back there i wouldn't know where to start!

any help would be massively appreciated,

James

There must be a section on pre amplified output in the user manual, if your head unit has that facility that is.