I have one car that has some minor alternator whine in the sound system at high volume, easiest heard with nothing playing, obviously. Wife doesn't notice (her car), but irritates me.

So, I acquired an alternator suppressor module (and premium sound 'wire') with an eye towards replacing hers. Unfortunately, I find no alternator suppressor on hers, nor bracket to mount one on. Okay, so that might be the problem, thinks me. Looked under/over/around my other two cars, see no obvious mounting brackets, or suppressors, either.

I stared at all three cars from below, using the diagram below, with no successful identification. I don't recognize the view there. The text seems to indicate it's from below, but no help to me.

Anyone have a notion where the suppressor should be relative to the alternator in an 2002 XK8? Or, alternatively, identify anything else in that picture below to use to orient?

I've put the suppressor across the battery terminals, and it helps noticeably at higher revs, but would prefer it under the hood/bonnet rather than floating around the trunk/boot. Probably works better there too...


Where in the world is Mr Suppressor?

 

B black wire on right feeds starter.
Hi Dale,
do you have any aftermarket stereo equipment installed at all?

If yes, I'd focus there. I'll assume no for now.

Dale, my extensive experience with car stereo installs and mods points to a bad connection in the sound system for noise like this. For some reason bad grounds seem to be the best culprit. After that look for less than perfect battery and ignition connections.

Unfortunately there are several components, head unit, cd changer, Amplifier, in the chain.

I'm not sure if you have premium system or not. I just looked, the amp has a local ground point in the trunk for premium. Other than that power comes from the radio.

The ground for the amp is ground # BT1CS. Do you have access to the documents that show ground location?
Dale taking the 20 minutes to disconnect, clean and polish the ground point and the ground connector can have a huge impact.

Did you know you can access the connectors on the back of the radio without disassembling anything? Just pull back the carpet folded over it in the footwell. I bet many folks wouldn't realize how much of the radio's ground circuit is carried over the antenna connection.

Pull the cd cartridge (you want to turn up volume but have no music getting in the way, I dont think any of our factorysystems have a mute button) turn on engine, turn up volume to amplify the whine. Reach in, twist and wiggle the antenna connection to the radio - any change? Yea, I'm going to suggest disconnecting it, reconnect it to clean the connection, but turn the volume down a bit first!

Replace antenna connection, volume up, wiggle the wires into the radio looking for bad connection. As I recall, the radio output (power signal control) is carried by a DIN plug so probably not much detective work you can do there.

Dale, I've gotta figure these tests are nothing compared to getting to the connections on the alternator. I hope the amp ground clears things up a whole lot for you mate.

John

 

Appreciate it, John.

Have done most of this, cleaned every connection I can clean in the rear. Yes, premium system. Yes, aftermarket handsfree, but also happens without to some degree. The whine really is only apparent at higher revs. There's some minor amount of amplification in the handsfree that is making it worse (again, for me, not particularly her).
One thing I haven't done on hers is to play with the antenna. Next on the list while I continue to search for the location of the suppressor...

Again, appreciate it.

 

Plain-as-day in the XK Electrical Guide.

SUPPRESSION MODULE-- AN3 / 2-WAY ECONOSEAL III LC/ RED-- REARWARD OF RIGHT FRONT HEADLAMP

 

Thanks Bob.

Typical failing of mine. Usually, I just go straight to the pictures. (What? 'Cat in the Hat' had text?)

 

Sounds good,let us know how you do.

John

 

So, a couple of things. There's no evidence any of mine have suppression modules, or ever had suppression modules. Nothing in the correct location(s). Apparently two locations can be right next to the AC drier (pictured, not mine, below) and in the wheel well behind the light (have not found a picture of this). I cleaned everything, polished all the grounds, wiggled everything at the amp and aerial and radio, and I guess it's marginally better, at least the basic noise is qualitatively better. Can still hear the alternator whine at very high amplification, but not above any music or phone, which is still theoretically irritating to me (more later).

So, I tried putting the suppression module across the battery, which changes the noise a bit, but doesn't get rid of it. I expected some phase lag from overall resistance between the alternator and the battery, however, it may introduce mildly malevolent ghosts into the system in this use, especially in the climate module and in the radio. Things turned off when they should have been on, buttons did not operate properly and things turned on when I thought they were off over the course of a couple of weeks. In theory, I could sneak the module connector onto the alternator, but I have no mounts on any car, so I hadn't done that yet.

So, today, I decided to see if I could finally get rid of it. I started with a road session, and my wife accompanied me (only explanation is that she is bored senseless). I tested the phone at various levels, the radio at various levels, the CD at various levels and the bluetooth at various levels to max, and without anything at various levels, with and without wiggling.

Lovely assistant: "You're not fixing anything, I'd never turn the stereo up anywhere near that loud."
Dale: "But you can hear it when it's turned way up with nothing on."
Lovely assistant: "Exactly."

So, 'fixed'. Declaring victory and leaving the battlefield.


Here's one of the places where the suppression module would be if it was there in my cars, which it is not. This picture was stolen from others.

 

Loved the dialog - thanks for the laugh.

 

Dale,

Hehe! Been there and had that experience too with the other half.

Don’t forget the other expression “It wasn’t broke until you touched it! You’ve just made it worst!”

 

First thing mine does is turn the radio off, in MY truck, MY Triumph or her Rogue. Problem, lucky for me does not exist. LOL
Surely it's because I would miss something very important she has to say. I'll suffer for that comment.

 

That didn't last forever. A year and half later, while in the console for other purposes, I decided to find and eliminate the irritating noise (that I could still hear clearly, and it turns out my son could also hear clearly). I learned a number of things

1. Once you have one used Jag noise suppression module (LJA1820AA), don't bother getting any others. Based on an n of 4 acquired through various means, they are all broken. This makes sense since the rather large capacitors in them don't last forever.

2. Which means, you either need to replace the cap in a used module or buy a new module (about 120 GBP). I bought new after exploring the capacitor alternatives.

3. It has never been clear to me where this module goes in my model cars. So, I made up a new bracket for the module and put it onto two exposed screws behind the right headlight in the wheel well.

https://www.jaguarforums.com/forum/x...th-add-250924/

4. The two main sources of noise in my cars that is getting into my bluetooth setup are the alternator (much larger sound) and the throttle position sensor (very very minor, you can find many things with an oscilloscope, but for some reason this is also audible in the air without the engine on).

5. It's pretty easy to rearrange the relays in the ECM/TCM compartment. Someone apparently did this before I acquired the car, and that made figuring out 4. quite confusing for a while. The relays are in their correct place now...

6. I reduced the TPS-induced noise quite substantially with one of these. Before, it was only possible to hear that noise with all the music inputs off and the volume most or all of the way up. After, almost nothing at the highest volume.

https://www.discountcarstereo.com/nf3a.html

7. Things that did not work on the alternator noise other than the giant expensive Jaguar cap included ultra low noise linear regulated supply off of the cell phone power in the console, any of the small filters such as in 5. alone.

8. Things that did work on the alternator noise were the giant expensive Jaguar capacitor and an externally powered (grounded to house power) linear laboratory low noise power supply. The latter seemed impractical owing to the rather long power cord necessary for a trip to the grocery.

So, actual victory. Better than the illusion of victory, and less personally irritating.

 

Well done. And now, no 25-mile-long power cord needed....

 

The standard suppression is a 3 uf capacitor from the alternator output terminal B to earth ....

 

The XK8 one is a 22,000 uf capacitor (0.022 F). Picture below.

You can get a similar capacitor, these days, but not from Philips (apparently sold that bit off). I had difficulty finding one that would go exactly into the XK8 can.


Big honking cap.

 

That is a smoothing capacitor intended to remove the ripple from the rectified 3 phase alternator output. The 3 uf bypasses RF noise to earth. This usually shows up as a whirring sound varying with engine speed on an audio system.

 

Yes, the "Jaguar Alternator Suppression Module" (the 'honking' one I've been talking about) is intended to reduce/remove the ripple from the alternator affecting premium sound quality. This is connected from the B terminal to earth. If I add another 3 uF in parallel (i.e. also from B to ground), I have an equivalent 22,003 uF cap. So, I'm not getting a discernible effect from the 3 uF cap.

If I only use a 3 uF cap, I'm not using the 22,000 uF capacitor spec'ed by Jag that I bought at great expense...

Perhaps I have missed your point.

 

True you have.

 

That's a bigger boy than I would have expected. Also to be found in non-switched-mode low voltage power supplies.

It's common in electronic circuits to wire a lower-value non-polarised capacitor in parallel with an electrolytic in certain circumstances. A whole separate subject:- google 'capacitor ESR' if you're somewhat bored at the moment

 

in the immortal words of my daughter, “Really helpful dude!”.

 

Michealh has it. One is for smoothing and one is to bypass radio frequency interference which is what I originally said.
"There are none so blind as those who cannot see " As my old maths tutor said many times.