I'm trying to upgrade the stereo, specifically the head unit. Upon installing it, it does work, but with very low quality, as in I get loud pops, and static noise, and can feel static electricity emit from the speakers. Has anyone else had this issue. Looks like the amplifier looks for a 0-30 millivolt signal coming from the stereo, but when I had the new stereo plugged in, it was putting out around 5 volts. Can anyone share some insight as to what stereo system they put without any audio issues?

I have the HK premium system with the sub near the back window.

 

I eliminated the factory amp because it is wired specifically for the original head unit and it powers it. Because it also goes through the GPS and CD also, which have their specific power routing through the amp. You'll get better performance simply bypassing that amp and using just the replacement head unit direct. That modern replacement head unit is also set up for providing its own power to the system vs the 20 yr old Jag unit. It took me a couple of hours of sitting in the trunk sorting out the wires, but I used a 3rd party coupler and bypassed it that way initially. Later I put in my own amps and still used the couplers for a possible bypass in case something breaks or when I change something again. Which is going to happen soon, I am putting bass directly into the back of the drivers seat, so I'll be rewiring again.

Here are some overview pics, I had to unravel my nice tuck away for this ...I used a white piece of cardboard to hopefully make viewing better?

 

I kind of figured the right way to go about this after the whole ordeal, is to put my own stereo system like you. I decide to put the old system back--I like being alive and not electrocuted.

What size amp did you use? How difficult was splicing and figuring out the wiring?

 

Well, first off, you can't get electrocuted with 12v and 18 gauge wire....lol....like I said, it took a couple hours of trunk and beer time, along with working out the wiring behind the dash. Don't be intimidated by the amount of wire you see in this link, there are a couple extra things I have attached (Sirius and separate navigation piece) that make it look intimidating. https://www.jaguarforums.com/forum/x...-piece-165345/

The thing to keep in mind is with the premium sound, the wire runs from the head unit, to the trunk amp/cd/nav and back forward out to the doors. The color codes are listed in the schematic link. A simple multimeter is a must and most of your chasing will be done using a continuity loop.

Here's the schematic for the XJ electrical layout. http://www.jagrepair.com/images/Auto.../jagxj1999.pdf You need to use the Premium Stereo guide (page 82) since you say you have the amp. As for the amp I use, its in the pic, its an old Alpine Alpine MRP F240 I've had for awhile. There are much smaller and better units nowadays, but it works, I'm not out to blow out the neighbors and I don't have to buy another one. Though with the new smaller ones that may fit behind the glove box, https://www.sonicelectronix.com/cat_...mini-amps.html ...its tempting to swap out?

Plus, I don't know if you noticed the new upgrade on the site, where if your in a thread and scroll down it automatically attaches threads that it deems similar. Its not the most accurate, but can save time chasing other threads.

 

If you're going to the trouble of pulling things apart, you might want to think about running RCA cables from your new headunit to the trunk, into a new amp (something small is fine, you don't need more than 50wrms x4), and then using the stock wiring from the original amp to run back to the speakers.
You'll want to pay close attention to the wiring diagram Highhorse posted though, because the front tweeter and mid-range speakers are all powered independently, so you may need to do some re-wiring in the doors.

What speakers are you looking at using? If you get component speakers this should make things easier... I would advise talking to someone who knows what they're doing though. A few little details now will make for a big improvement in the stereo

 

This is the way I would do it if I was replacing the head unit and looking to "do it right the first time." A 4 channel RCA (or 5 channel if doing a sub, and the HU supports it) is way easier to run than a mess of speaker wires from the HU to trunk, especially since all the speaker wiring is run to the trunk already. Sure, if you didn't want to use a separate amp, and didn't want to run speaker wiring from the HU to the trunk harness, you could run all new wiring direct from the HU to the speakers bypassing factory wiring completely, but that's a lot of work that doesn't make sense to do, you'll be pulling door cards and carpeting and tons of trim.

If you're running a subwoofer, you can get a 5 channel amp. If your HU only has 4 outputs, certain 5 channel amps will take the front L/R signals and share them between the front L/R speakers and the sub channel. That's ideal, and my plan for a factory amp bypass one day once the rest of the car is dialed.

As to the tweeters, you would need to set up some kind of crossover to limit the signal. (this only applies for the fronts for premium systems with A-post tweeters, if you have tweeters in the doors then they already have crossovers set up and you can ignore everything after this. Rears on both premium and basic have crossovers set up already). The simple thing to do would be to just run both the tweeter and midbass on each front channel in parallel, but put a bass-limiting capacitor in series with the tweeter - not the best sound quality but you won't blow out your tweeter. You can also set up a proper crossover to split frequency ranges between the tweeter and midbass - you could put these near the amp (easier to install) or in the doors (better quality). On my old car I had crossovers in the trunk and that setup got some inductive whine from the fuel pump nearby, but that was a pretty kludge setup, I'm sure spending an hour diagnosing and shielding that would have solved it. At this point you may as well upgrade your speakers themselves, a lot of quality automotive component sets come with crossovers tuned to them. Here's an easy example, may or may not fit in the Jag https://www.morelhifi.com/product/maximo-2-way/