406 Exec factory JBL amp?

maglite · Post by **maglite** » Tue Feb 27, 2007 1:20 am

Hi, guys... and girls (if there are any), I changed the headunit in my Mk2 and there wasn't any sound untill I connected the blue remote lead. But when I did that, the sound is being amplified by a JBL amp somewhere in the car. Does anyone know a way of bypassing it because it's making a terrible hissing sound in the background of the music.

Any help much appreciated.

Post by **DaiRees** » Tue Feb 27, 2007 7:31 am

The JBL amp is in the boot, on the right behind the panel....

...at least that's where it is on my estate

maglite · Post by **maglite** » Tue Feb 27, 2007 2:03 pm

Ok thanks, I will be sure to have a little look there today to see if I can bypass it somehow

Rick_J · Post by **Rick_J** » Fri Mar 09, 2007 9:52 pm

most coupes suffer from this. its hissing because the new headunit is amplifying the signal and then feeding it into the amp which isnt god. you have 2 choices - bypass the amp or change the head unit to feed preouts into the iso connector (better)

niz406 · Post by **niz406** » Fri Mar 09, 2007 11:07 pm

Or insert a high level output filter or hardwire some RCA leads as Rick mentioned....

With the highlevel filter you can lower the throughput which should remove the noise, you can also use a ground loop isolator, which is required to stop any buzzing, hissing or interfearance when the headlights are on... le me know what you want to do as I have the filter and isolator available if you want them ?

jameslxdt · Post by **jameslxdt** » Fri Mar 09, 2007 11:09 pm

or you could remove the amp and give it to me

paul · Post by **paul** » Mon Apr 16, 2007 11:23 pm

I take it that it's just the exec that has this amp as I can't see one in my car (99 GLX Hdi estate) but the manual is a bit cryptic about it.

Post by **DaiRees** » Mon Apr 16, 2007 11:29 pm

I think the GTX may have had it as well

mjb · Post by **mjb** » Mon Apr 16, 2007 11:44 pm

D8 execs didn't get it *grumble*

paul · Post by **paul** » Tue Apr 17, 2007 9:43 am

Well, I've got the cd player behind the left panel in the boot but just a plastic storage tray in the right hand side, so no amp for me then.

maglite · Post by **maglite** » Fri May 04, 2007 12:33 pm

niz406 wrote:Or insert a high level output filter or hardwire some RCA leads as Rick mentioned....

With the highlevel filter you can lower the throughput which should remove the noise, you can also use a ground loop isolator, which is required to stop any buzzing, hissing or interfearance when the headlights are on... le me know what you want to do as I have the filter and isolator available if you want them ?

I'm going to install an amp wiring kit this weekend, so I'll be messing around with the stereo. I'll try hard wiring the RCA pre-outs directly into the ISO connector. Hopefully that will resolve the hissing issue. I just hope that I don't get any major vibration on the D9.

Is there a good place that anyone can recommend to pass my amp power wire through from the engine bay, it's 4 AWG, so it is fairly wide

jameslxdt · Post by **jameslxdt** » Fri May 04, 2007 6:50 pm

if you decide to ditch the jbl amp...
ill have it

Black Pearl · Post by **Black Pearl** » Wed Oct 10, 2007 9:27 pm

Ayup all,

just noticed some folk are having trouble locating the amp, as i did when i lost my rear channels on my old standard cassette head unit, seemed strange the executive model having an amp the jbl speakers and an old skool tape deck lodged in me dash, but i soon got me a standard cd player from the scrappy, got it coded to me car, jobs a good un. but ive found on the d9 saloon model the amp is located behind the rear wheel arch behind the carpeted trim, it sits below the sat nav cd rom, which is a bit of a pain in the arse when ya faultfinding for lost channels, id imagine it would be in the same place with or without the sat nav. Though i have noticed since fitting the cd player the output is a lot louder than the old tape player model, specially if you turn it up to a meger 5 on the scale it blows ya head off, not that i mind

and there is a slight hissing if the head unit is off or turned down without the loud mode selected, im pretty sure it comes from the audio feed from the sat nav as when i unplugged it the hissing stopped. aint found out how to cure this just yet as it aint much of a bother.

hope this is of some worth to someone out there

Post by **DaiRees** » Thu Oct 11, 2007 7:31 am

Black Pearl wrote:Though i have noticed since fitting the cd player the output is a lot louder than the old tape player model, specially if you turn it up to a meger 5 on the scale it blows ya head off, not that i mind and there is a slight hissing if the head unit is off or turned down without the loud mode selected, im pretty sure it comes from the audio feed from the sat nav as when i unplugged it the hissing stopped. aint found out how to cure this just yet as it aint much of a bother.

Ah now pearl, this subject's been on here before too. I think the upshot was that there's a setting on the head unit to tell it if it's amplified or not. Then it adjusts it's output volume accordingly. i.e. amped = low output, unamped = high output. Therefore if the stereo thinks it's not externally amplified then when you run it through the amp the volume is too high, in fact i think the original thread was along the lines of someone not being able to get the volume low enough to be able to hold a comfortable conversation in the car, even with the vol on 1.