Hello, all. The radio and cd player in my 1998 XK8 convertible make a whining noise when I drive, which gets higher the faster I drive. The whining happens even when the sound is turned down all the way, but not when the radio or cd player is turned off. Also, my rear speakers are shot.

I went to a car audio shop (with great reviews on Yelp), to make an appointment to have the rear speakers replaced, and to ask about the whining noise. The man there (without driving the car and hearing the noise) said the noise may be happening because my amplifier is dying and, if so, I'll have to replace it with a Jaguar amplifier made for my XK8 my car model (which I gather is a Harman Kardon amp, Part No. LJB4170BA). I looked online for that amp, and it appears that a new one costs over $900 US! (There are used ones for under $175.) I don't need a premium sound system; just a basic one that doesn't whine.

I hesitate to order a Jag amp without knowing for sure if my amp is indeed dying. I have the following questions:

1) Can my amp be tested and, if so, how?
2) I worry that a used XK8 amp may produce the same problem as mine does, since it will be the same age. Is this likely? When sellers say it has been tested and works well, would they actually KNOW if their amp whines?
3) Is there an alternative to getting another XK8 amp, short of replacing my whole sound system? (My front speakers, radio & cd player are all fine as is.)

Thanks for any help you can give me!

Nicole

 

Any amp will work as long as it has the same connectors . A crossover network to drive a woofer is installed as the premium option inside the original Jaguar amp and can be optional if you replace it . Mounting could be an issue . The grounds on the shielded wires may be bad as well as the noise suppressor external to the alternator . The alternator diodes may be tested at the auto parts store if you ask for that test .

To test the noise suppressor put a meter on resistance and watch the value climb as the meter charges it up with electrons . You can short it and watch it climb again .

The whining happens even when the sound is turned down all the way is a indication of a bad ground allowing a stray signal to be picked up by the audio line in wires , not a problem with the amp

Speakers can be repaired yourself and save some money , about $ 8 a speaker for parts .

Have you looked for loose cable connections on the control head as well as it's ground strap ?

Any questions , just ask .

 

I can't do this stuff myself, and the shop I consulted had an OK price for speakers. Question: could/should he (who just does car audio) be able to do all of the things you suggest? Thanks.

 

Yes , except for the alternator test for bad diodes

The suppressor test is for a capacitor as that is what it is

A audio shop should have a amplifier around they can swap out for testing

 

Msterieus,
What you have described sounds like classic alternator whine, which is much more likely to be a result of poor suppression/bad grounding, as Lady P suggests, rather than a 'dying' amp and should be a straightforward troubleshoot for any audio tech worth his salt.

The 98 has a 'suppression module' above the alternator (circled in attachment, courtesy of MadBrad). Check if that has been disconnected - or removed.

Simple checks first before spending $$$.

Mike

 

Sorry - don't want to contradict, but I'm not sure all of the above is true.

On the "basic" system, there is no separate amplifier. The head unit contains all the circuitry to take inputs from radio, Cassette and CD player, and sends the output to four speakers.

On the "premium" system, the (same) head unit sends a low-level audio signal to the amplifier in the trunk/boot which has four-way active crossover circuits which drive ten separate speakers (nine in the coupe).

First thing I would check is the suppression module :
https://www.ebay.co.uk/itm/JAGUAR-AL...-/222596790036

If this is disconnected or faulty, it may lead to the symptoms you describe.

Any amp will not necessarily work, even with the correct connectors.

Do you have the little triangular "tweeters" on the inside of the car where the door mirrors are ? That will show whether or not you have the "standard" or "premium" system, and we can take it from there.

Edit : was writing while Mike was posting !!

 

Great minds

I took that the OP has premium but that may be from the tech's remote diagnosis...

 

Thanks, Devon.

How "little" are these tweeters supposed to be? The speakers near my side mirrors are SORT of triangular, but the 3 "angles" are actually rounded. They measure roughly 2.75 x 2 inches.

 

I just checked again. Yes, I do have triangular tweeters in the doors. Does that mean I have the premium package?

 

Yes - it would appear that you have the "premium" system.

It isn't really possible to convert back to a "standard" set-up.

Rear speakers are in proper "cabinets" on each side of the rear seats. It isn't difficult to replace them - just a bit fiddly and does involve removing the rear seats and side-panels to do it properly.
Depending on your location, fairly good replacements are available for not a great deal of money - do a search on "XK8 rear speaker replacement" and you'll find lots of information.

e g - here :

http://jagrepair.com/XK8SpeakerReplacement.htm

But - I would check (or get checked) that suppression module. That may explain the whine noise.

The amplifier (which is on a rack in the boot / trunk next to the CD changer) may be faulty, but it's fairly unusual - they usually either work, or don't work.

I guess the other explanation could be an aerial / antenna problem. Does that work OK ? Has the head unit ben removed to check all the plugs and the big earthing connector at the rear ?

 

Thanks for your help, everyone. I will print this out and take it to the audio shop next week, when they will replace the rear speakers, and (hopefully) test the amp/whining noise with these useful suggestions!

Nicole

 

Let us know how you get on, and don't take too much "You need a new amplifier at $1zillion to get it working OK." - probably not true.
Get the whining noise sorted first (suppression module probably) then it's maximum 3 hours labour plus less than $100 parts for new rear speakers.

 

Does the frequency of pitch of the whine follow the speed of the car or the RPM of the engine as it shifts through gears ? This would be a determination to eliminate the alternator and the suppression module or a bad ground wire .

 

Lady P: I THINK the pitch of the whine gets higher the faster I go, but I haven't focused on whether it is RPMs. However, since pitch goes up even when I go from 5 MPH to 10 MPH, I suspect it is speed - not RPMs. I will check, though, the next time I drive the Jag. Thanks.

David: The antenna works fine.

David: I'll keep you posted. (Note: 3 hours of labor, here in No. California, is $$$! I just had a shower door installed, and the seller charged $300/hour for that simple service.) House cleaners charge $150 to clean a small (1,400 square foot) house.

 

Have you checked the speaker is actually there and not just the empty "sail" trim? That tweeter is actually only around 1" diameter from memory.

 

The black wire on the suppressor goes to ground and may have been disturbed during alternator change . Or it's grounding point may be corroded or dirty .

 

Hi, all. Well, I went to the car audio place today and gave Philipe a copy of this thread (and made him promise to read it, as he seemed dubious). He put in two new rear speakers and checked on the whining noise. The good news is that it sounds like I don't need a new amp - he thinks the problem is with either a diode on the alternator or with the suppressor (as some of you stated). The not great news is that he did not deal with this problem but said I must have a mechanic do it.

He also was not able to deal with my CD player, which is stuck and won't eject. I have to go to someone who fixes CD players; he does not do that! My my, but car audio places certainly are specialized here.

PS: Can any mechanic check on the suppressor and alternator, or do I need to go to someone who is experienced with fixing Jags?

Thanks much!

 

Actually, my statement about the cause of whining was wrong. Philipe said he could not check the amp itself, because it needed to be tested with particular Jag components that he did not have, nor could he check alternator/suppression, because he wasn't a mechanic. So, cause was still unknown...

BUT: I picked up the car, with the new speakers, and guess what? The whining noise is GONE!

So now, I only need to work on the CD-stuck problem. (I recall reading a thread about it on this site; need to find it and reread.)

 

Philipe could have fumbled with the wire connections or the grounds , good news it's not hardware related like a alternator , suppressor , or amplifier . So if it returns you have it narrowed down .

Although it doesn't show one on the wiring schematic you would think there is a separate fuse for the CD player alone . Not knowing where it is you can feel with your hand if it is warm like the amplifier as a sign that it is getting power . This would take some time for it to warm up .

There was a mention on a different topic today of a noise suppressor on the fuel pump power wire , see page 25 on the left side for the fuel pump although it does not show a suppressor . This suppressor is different then the one by the alternator .

http://www.jagrepair.com/images/Auto.../jagxk1998.pdf

 

The CD has power: it plays all the CDs inside of it. (I'm getting pretty tired of listening to the same CDs all year, though.)

Also, when I tried, today, ejecting the CD player by sliding a knife underneath it, there were occasionally a few sparks. :{ I'll try again tomorrow with a credit card or something else not metal.

I believe I read some post on this site that said there is NOT a separate fuse for the CD player.