***Install aftermarket head unit in MOST car WITHOUT removing factory amp***

I have found a way to install any aftermarket stereo in the 03+ Porsche cars with fiber optic ring WITHOUT the need to replace the factory amplifier. This makes installation much more simple and less evasive to the car. No more needing to wire in amps, and rca cables and speaker wires etc... it can all be done now right from the dashboard. The device is available to my knowledge only here https://m.aliexpress.com/item/32708723316.html?trace=wwwdetail2mobilesitedetail& productId=32708723316&productSubject=RCA-audio-adapter-kit-fit-Benz-Porsche-fiber-optic-power-amplifier-to-aftermarket-Car-DVD-GPS The installation is easy power ground and accessory just like an aftermarket head unit. Simply hook up to the same places your hooking up your new deck. Porsche 996 rca to most fiber optic converter - YouTube

It would be nice to see if anyone else has experience with this. If it works that's great.

I ordered one, will use it on my 04 with a Alpine BT149 HU, will stop at CAI and pick up a plug and play harness from them and have them piggy back this comverter to the harness.

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Quote: How did it go? Works well? Scott

it works amazing, and was pretty much plug and play with CAI harness and piggyback the converter harness in between. sounds from the Alpine BT149 head unit makes a big difference in sound quality while still using the fiber optic amp and oem speakers. the only thing you lose is the fader adjustments, which I never use. hardest part is wiring in the acc. wire to the key switch to maintain the radio don't shut off till key is removed from the ignition. the fiber optic coming from the amp plugs right into the converter.

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Quote: Thanks, I am ordering today. What was so hard about acc wiring, space? Isn't the previous radio already wired for that? Could you not tap into? Scott

Yes, position is tough for big old fart like me at 6 ft. and 225

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Quote: Would like to confirm you have an 04 with the Bose MOST. The adapter web page says it is for 2005 - 2011. I believe those years had a different system than the 04 (that I have as well). Scott

Yes , it will work on the 03 and 04 MOST systems.

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Quote: John, Saw today in Renlist you posted https://cai-store.com/collections/al...ant=3737574725. I found this a few days ago as well. I think it plugs directly in to the head unit, correct? Do I tell CAI which unit? (They are closed today.) Do I understand correctly that you only need to connect the two power wires and you are good to go? (Assuming I have the MOST converter installed.) Scott

the CAI harness is made for the Alpine BT149 deck, great deck, I actually use the plug for another Alpine unit so I could finish the harness before my deck arrive, there 3 wires that are used from the P-car harness to the deck, and the acc fused wire to the key switch. CAI is going to tell you it won't work because it is listed for use on 05 and up, so I ask them if they had try it, and he was honest and said no. I would ask for a harness and antenna adapter, you could ask if they have a connector for your radio you plan to use.

Just want to add another confirmation to this thread. The device works great. Just installed a Kenwood DDX9903S double din. Plugged it in an fired right up. Sounds better than ever. You do need to let it cycle one with the key out of the ignition but after that all if great. My Becker is now a door stop. Scott

thought about selling my Becker, but door stop would be better use.

Installed mine last night and have no sound. I do have a blinking light coming from the converter and also on the fiber optic line when I unplug from the amp. I have replaced the D9 fuse for the amp, which looked fine. Any suggestions? I did hook both power lines (red and yellow) on the convert to switched power. I wouldn't think this would be the issue.

Two questions, did the radio work before you did the install ? also did you do the key on and then off for 90 seconds on the first time turning on the installed unit ?

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Quote: No the radio appeared to be in a constant state of resetting itself. It would work sporadicly. I thought it was the head-unit and not the amp but I may be wrong. I did cycle the key on and then off for 90 secs and back on.

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Quote: I do think your problem is with the red/yellow wire at the same source. I think the unit needs a constant source of low power. The instructions are specific about resetting the unit after installation. I do not think yours ever resets properly. Scott

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Quote: Scott, I was was thinking the same thing and connected the yellow wire per the manufacturer's website to constant 12volt and still have no luck. The amp doesn't appear to be powering on. I'm assuming that the most signal tells the amp to kick on? I'm stumped. I'm thinking my amp is toast but not sure how to go about veryfying this is the case.

It turns out I had a bad head unit and amp. I removed the Bose HU and AMP and replaced with an Alpine HU and Polk 5 channel amp. Very pleased with the new set-up.

Will this work on a 2002? I only want to connect this and the Alpine HU to Bose system.

The 02 did not have the MOST system, you don't need the converter.

So there is nothing that I need to hook up an Alpine HU?

Nope, so either cut up the P-car harness to wire in or go with CAI wiring for plug and play, they specialize in Porsche installs. https://cai-store.com/

I just completed this on my 2003 carrerra 2 with the MOST HI FI system. I brought the adapter from alliexpress.com. I used a Kenwood ddx375BT double dinn head unit. I used a metra harness and metra install kit. Total cost was approx 450 dollars. The system works but needs a little tweaking. One problem is that the volume for the radio is fine but on bluetooth streaming the volume is too low even when output from the head unit is turned up. There may be some way to increase the output at the amplifier but I do not know. Also the backup camera only works when I manually turn it on from the head unit, it should turn on when I put the car in reverse automatically. I know iot is hooked up right because I have to put it reverse to work. If I just turn on the camera from the head unit the system will not turn on, the car must be in reverse. Other than that it seems to work fine and looks good. You can easily spend 1500 to 2500 for full installation including new speakers and amplifier. I just wantred something a little better with iphone connectivity.

I got almost all of the kinks I mentioned previously out of it. The only problem now is that when I turn off the car there is a pop sound. I think the amp and radio are turning off at the same time sending this annoying sound through the speakers. Any advice on what to do about that?

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Quote: I just ordered the adapter from aliexpress. Trying to figure out what head unit to order. Did you get the Bluetooth volume and backup camera figured out for the Kenwood? Any other head units someone would recommend that are known to be working?

I did get it figured out, it was my fault I had the bluetooth mic hooked up wrong and the backup camera was also hooked up incorrectly. Once I fixed that they both work. My only issue now is a slight popping noise when I turn the car off. It think I need to set up a slight shut off delay between the amp and the radio but I'm not sure and still trying to research that.

That is good to know. Please keep us posted. I currently have a Dension Gateway 500 and I recall some alternator noise problems related to the power connection type. The recommendation was to use a different constant power that has a bigger diameter and shielded + ground connection for the aux (that I use for BT that works but not great). The problem was more of a wining sound so it may be a completely different issue than the popping noise. I like the specs for the Kenwood - finally after 14 years there's hope to the replace the HU :-)

In my case I get this anoying click or popping sound when the ignition is turned off even if the radio is off. Searching other car audio forums suggest that the problem is that when the amp goes off the noise is generated. Still looking into how to correct this but overall the stereo works well, a big improvement over the CDR-23 even with the same amp and speakers.

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Quote: Converting the MOST based systems to mate aftermarket HUs is not without it's drawbacks like the popping sound you hear. Here's my hypothesis... Normally, with a MOST based head-unit, you have digital output signal that "talks" to the amps or other peripherals. These types of more modern audio systems mute the digital audio signal feeding the amp BEFORE the 12V switched current to the amp is turned off. The head unit that you are using is NOT muting the pre-amp output BEFORE the 12V switched output to the amp is turned off. This problem is similar to a electric guitar player connecting to an amplifier/speaker with the volume output wide on the instrument wide open and the gain turned up on the amp. When the phone plug from the guitar is connected, you hear a loud pop because the positive terminal of the male phone plug touches the ground in the female connector of the amp. Since these amplifiers produce an enormous amount of sound pressure, the popping sound can be deafening. Try a simple test - mute or turn the volume on the HU to it's lowest level, then turn off the car. Does it still pop?

Tried that, it still pops, even on mute.

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Quote: The MOST conversion box could still be proving a constant digital audio signal even if you unplugged the analog pre-amp output from your HU or turned down the volume. Have you tried disconnecting the power from the MOST conversion box and then turning off power to the HU? This would tell us if the pop is being caused by the AliExpress box. How are you harnessing to the remaining factory radio cables?

I disconnected power to the MOST conversion box leaving ground connected. No popping noise but no sound as well. I had switched power from the Porsche harness connected to both the head unit and the MOST adapter. Constant power was connected from an unused factory cell phone harness to both the MOST and the Head unit. I tested these just to make sure they worked properly. Perhaps if I install a timer to turn the amp off first before the head unit goes off the noise will go away. I found a couple of these inline timers on Amazon. I think when they are going off at the same time the noise is generated. Thanks for your advice by the way.

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Quote: IMHO, you should use the constant and switched 12V power from the Porsche radio harness which feed the HU and frunk amp. Use the phone connector's switched 12V and ground to power and ground to the MOST conversion box. The amp could still pop when it's powered on, if there is a strong audio signal feeding regardless if it's an analog or digital type audio signal. It would be better if the MOST conversion box muted the digital audio signal, then turned off BEFORE the amp and HU when powering down the system. My father was an military trained engineer and after his service, installed Becker radios in the Porsches back when we lived in Atlanta. As a kid, I enjoyed listening to his instructions and hearing all the in depth analysis of properly matching components on a audio system. Does that make me an expert? Absolutely not! hahaha But I learned a lot for him. He is still a very good bench technician that can get down to the component level on a circuit board. Why am I saying all of this? Because I've dealt with your problem many times over the years. If I'm not mistaken, the proper start up and shut down procedure should go like this... Power on > Head unit powers > 12V to amp turned on (internally or externally via pre-amp > audio signal sent to amp(s) > speakers receive signal Power off > audio signal muted to amp(s) > Amp turned off > HU turns off Because amp pops are common, some aftermarket units will allow you to delay the pre-amp audio signal output. This is a setting in the preferences menu. Unfortunately, we have NO way of knowing how the analog to MOST converter box is handling the optical signal output. It's probably keeping the digital audio signal active even if it sees an pre-amp analog signal or not. It probably comes on fully active when the switched 12V turns the unit on. That may mean that even if you can delay the audio signal from the HU, it will still cause a popping sound. If you could put a delay on the switched 12V feeding the conversion box, that would be a great test. Hope you find a solution!

I have a different problem. I just installed my box and a Kenwood stereo. I had some wining noise when I started the car so I installed a noise isolator as well. I took it for a long drive and everything worked fine. On the way back the sound started to chip out - the sound comes and goes every couple of seconds. Turning off the HU I can hear a whining noise come and go. I stopped the car, turned off ignition and back on again. It is still there. Has anyone else experienced this? I suspect/hope there's some glitch (wiring). Will have to take out the HU to troubleshoot... I was reading somewhere that someone else had a similar problem and the conclusion was that the box was bad. I sure hope that is not the case. It was working great for a while.

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Problem solved. Quote:

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Quote: What was the solution?

I put in MPOW ground loop insulation that I had laying around instead of PAC-SN1. That fixed it. The problem started when I turned on the vents above the HU. When I turned off the vents there was still some whining noise with the PAC loop isolation. The MPOW fixed it.

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Quote: Super! Ground loop problems are some of the most common issues with sound systems.

In case this might help someone else: someone mentioned that the alternator cable runs through the bottom of the center column next to the unused phone connector. Guess what - I moved the phone connector I use for 12v switch power to the MOST box as far away I as I could to the passenger side. The whining noise is gone and I no longer need the noise isolator.

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Quote: Moving the analog to MOST conversion box away from the high current power line is a smart decision. It's not uncommon that electronics lack the shielding necessary to prevent noise or interference from other devices.

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Quote: Did you get this fixed? I have having same issue, I hear a loud pop when I turn off ignition and radio turns off.

I ultimately gave up and installed a traditional amp, works much better overall.

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Quote: Hi Posting my solution which this thread helped me arrive at. I have a 997 with bose. I replaced the HU for a Sony AX1005DB (great unit!) using the Connects2 MOST adapter cables. Everything worked great except for 2 things - no reception on FM and poping noise about 10 seconds after key was removed. Solution for the FM reception was to connect a switched power source to the white wire that is in the Porsche harness connector (the connector also has the brown (ground) and red/green (12v) wires). This white wire is for the built in FM aerial amplifier which for some reason the Connects2 adapters do not cater for. I just tapped this white wire to one of the red switched wire in the Connects2 adapter harness. For the audio pop I first tried a power delay module for the HU. The idea was to delay the power off of the HU to allow the Bose amp to power down before it. This didn’t work - all that this did was delay the whole problem! The HU stayed on for 15 seconds after the key was removed but so did the pesky amp! At least the pop noise would have now occurred when I’d left the vehicle!! In the end the solution was simple. The Connects2 MOST adapter takes a switched 12v source (red wire) from the ‘powered amp control’ connection in the Sony harness (blue/white stripped wire). This was creating a non optimum power down sequence for my setup so I moved this from the blue/white wire to a normal ‘switched power’ red wire (in this instance I just used the one in the Sony harness that HU itself also used. I now have no pop noise as the MOST adapter (and amp?) power down at the same time with no ‘white noise’ being amplified. Hope that makes sense - can post pics if needed. Cheers