My request is for several members of this forum to provide both experiences with XK PCM's and which vendor or manufacturer you would recommend. Negative comments are welcome as well along with installation and performance as advertised comments. For example, do you need to have the car dyno tuned when installing a chip or does a plug and play chip really work?
My Jag is a 2012 XK150 Base model with 50K miles on it and runs like a champ. Should I just be content with what I've got or go for 50 to 60 hp more?
Cheers

 

In fact the problem is the OEM system has an amp that does DSP too...they are 18 years old in engineering and they already were quite outdated at this time..
The DSP is supposed to be here to process the rough sound coming fron the source before it's amplified. This, if you have an home theater, is what translate the signal into DTS or DOlBY DIGITAL ...or emulates (specially if you have a Yamaha amp) a cathedral, a concert hall,a jazz saloon ...
In our XKs it allows to have Dolby as we have 5.1 speaker system...BUT it also attempt to "correct" the sound specifically for the car environment... And it's were it fails...deeply...and why the sound quality is unworthy of the car..

If you take that system off, you improve the sound quality. When you take the central unit off,you just keep the amp.So you improve quality of the sound as you improve the source quality.
Hope that helped.

 

Just a small point of order - we don't have 5.1 - we have LCRS.

 

There's 5.1
5.1 stand for
5 speakers. FRONT LEFT, FRONT RIGHT, CENTER, REAR LEFT, REAR RIGHT
+ 1 SUBWOOFER.

WE HAVE 5.1.
At least in my car it is.

5.1 relates TO THE SPEAKERS DISPOSITION . Not to how they are used... Dolby, DTS or not. (ps: there's dolby sound in mine)

 

OK, ok... ok...

"5.1" generally refers to a discrete 6-channel PCM digital stream, (L, C, R, rear L, rear R, Sub) such as delivered by Netflix, and on some DVDs and all Blu-rays, formatted as Dolby Digital or DTS, familiar in home cinema setups, but now increasingly being replaced with Atmos etc. Dolby Digital and DTS also support larger formats such as 7.1, 7.2, etc.

Dolby Pro Logic is a 4-channel stream encoded into an analogue stereo signal. Mono programme is steered to the centre speaker and lower frequencies are steered to the sub, with no discrete centre or sub channel. Rear programme material is identified by a proprietary phase/delay mechanism developed by Dolby and steered in MONO to the rears. There is no separate left and right rear. Running LCRS material into a stereo playback system produces fully compatible stereo reproduction. Running stereo material into a Dolby Pro Logic i.e. LCRS system will produce nothing at the rears, some mono such as dialogue in the centre, and low end through the sub. Dolby Digital or DTS material cannot be played out on a stereo or LCRS system without a dedicated decoder such as found in a cinema amp, and cannot be delivered on CD, via FM or DAB, or from an iPod.

 

@McJag222 I'm a deaf friend:-) Anyway, most of the units carry the TDA7850 amp which uses MOFSET tech vs standard BJT transmitter. OK so that said, I've no idea what our OEM unit has in terms of AMP but pretty sure it isn't MOFSET. To me the lossless sound required some tweaking of the settings but once in place I could hear everything (hearing aids still needed) but to my point, my wife's first comment on the unit was geez that's large screen. Her second was wow the music sounds incredible. She normally only listens to sports talk radio. Hope this helps.

 

Thanks Sean. So the Jag amp is part of the unit replaced?

 

Looking at the new Tesla Style heads. Is the memory in the unit upgradable? For example there's a pretty big price difference between say the 3/32 and the 6/128. Been upgrading my own PC's for years. Never liked paying extra for something low cost like memory.

 

I retract my earlier statement. There are prolly many MOSFET in our car as they are merely transistors. As I understand it, the 7850 amplifies a weak signal to the amp. There is no replacement of the OEM amp. The change is notable but someone with a bigger brain than me can probably explain the tech.

 

I haven’t studied the audio systems in the xk. However, I can tell you that the 7850 is a widely used opamp for isolation and buffering tasks. It’s not what you’d call an audiophile component.

As I say, I haven’t studied the audio setup, but the ‘amps’ you talk about are what I’d call ‘power amps’ - these do the end-stage heavy lifting to drive speakers and their input comes from ‘preamps’. Changing the preamps will potentially have a significant effect on audio quality. The preamps will be inside the head unit, original or replacement.

one caveat - it’s a well known phenomenon in the studio game that when you increase the volume, stuff sounds better. This has to do with how hearing works (and is the origin of the ‘loudness’ button first seen on Japanese hifi in the 70s. So, if a replacement setup is much louder, it may appear to sound better, with more top-end and more bass, even if it’s actually the same.

 

Like I said, someone with a bigger brain should explain, so thank you @justinhill , much appreciated. I lack the skillset to debate sound systems but can assure you it didn't sound better because the volume is higher. As I no longer have the unit and @arenaej now does, maybe he can better address the sound question..

Here is a link to the chip and there is a documentation tab:
https://www.st.com/en/automotive-inf...s/tda7850.html

 

finished my front splitter refurbishment. No, it isnt perfect but it is a far cray from the flat black paint and chipped mess it was.

I removed all the loose resin around the chips and with a brush and some diluted resin i managed to get good penetration under the pealing and flaking areas sealing and bonding them again.. I built the chips up with resin and then sanded them. Once happy i sanded and polished it all again. The underside was pretty beat up but actually cleaned up well. I decided to mask off the splitter and used a gloss black along the lower edge where it is most likely to scrape on my driveway etc. I figure this will be easier to touch up in the future. I guess I could just get a new mina replacement but i had never worked with carbon fiber and the resins before so it was a good learning project. Im happy enough, way better than it was.


added bonus. Powder coater called. Pick up my wheels tomorrow(gloss black)!


Before

Before

After

After

 

To my old ears, it’s not volume that made this radio sound better, it’s the level of adjustment that’s available. I’m not even close to an expert on the hardware or the tech involved, I just know what I like and this system is way better than the original…

 

@justinhill I worked for years in Home architecture and design and supervised Home theaters that were in magazines.. trust me I know about this. To me Meridian is High end theaters components... not car systems .
there's 5.1 speakers in the cars. I never said there's a DTS or DD decoder...
But the DSP use these 5.1 speakers to recreate an ambiance. Once again it's badly done... but it is... We have rear separate channels as far as i understood..The amp from what I understood is 5x xxW.
You can perfectly run DD in the car if you setup the right decoder. In fact I'm almost sure a Tesla screen could do it with the proper app if such apps who paid for it exists. .. But for sure I seriously doubt about netflix DD or DTS ...Branding something doesn't mean it's the real thing And you can for sure NEVER have DD DTS or whatsoever with just the 2 speakers from your tv or even a sound bar. These things are just marketing stuff for generations used to MP3 as highest quality sound available...
Anyway, it doesn't change anything to what I was explaining popularizing things for someone wondering...
I hope he now understand why changing the central unit greatly improve the quality .

 

No, there's no amp in the tesla screen.
It acts more like a preamp.

 

Have always experienced the higher the quality is, the lower you can appreciate it.
To me if a bad sound comes out of the machine, pushing the volume just emphasize the lacks in the range ... In the Xk first thing I done was pushing the level, searching for mediums ...then lowering the bass in the same goal... they never appeared...Pushing the sound higher impressed mostly people who never listen to audiophile systems..because then they feel what they don't hear. What's better in a car this is a large debate in the car/tunning world for years.

 

Do you mean there's a proper equalizer?

If yes wonder if having an auto Eq would be possible in such setup. that would be perfect!

 

@VegasFPace Really neat work! It really makes the car looks higher level.
You used Polyester or Epoxy resin for the touch ups and final coat?

 

There is an eq system. I guess I was premature in my recommendation of Navihua, the seller of my radio. As described in an earlier post, the hazard/pass seat belt switch doesn’t work. After much back and forth, sending video of a switch not working and testing the wires, they have stopped responding. I have no hazards and the airbag light is on. I’m posting this in the hopes that someone here knows how I can fashion a new switch or buy one somewhere…frustrating…

 

If your airbag light is on, your airbags probably won't work in a crash, you won't pass a state safety inspection, and you might not be able to sell your car. I would rip out that Tesla style screen and replace it with the OEM screen. I would never sacrifice my safety over a fancy screen.

Lesson learned. Buyer beware of buying anything directly from China, as they have your money and you may have no recourse, even if they say you do.