Belkin Auto Kit Direct Line in-Case Socket Modification

[Guy Kuo]

Here is how I modified my Belkin auto charging adapter so its audio output socket is a direct line out and bypasses the amplifier. Sound is definitely clearer without the Belkin's amplifier. There is an easier way to do this mod by using an external jack, but I wanted to make it extra neat and simply used the existing jack.

Here is the Belkin adapter taken most of the way apart. The trick to removing the PC board is to undo the plastic hook. That frees the PC board and you can push the thick cable into the plastic casing to separate the PC board from the casing.

[Guy Kuo]

Then desolder the socket. It take some patient melting of each contact while pulling up gentley. Each time you get a little more distance and eventually the socket is freed. Don't pull hard. Also, don't melt anything else while you do this. I suspect this one step is enough to deter most from doing it this way.

[Guy Kuo]

Here are the details of what the socket connectors do...

[Guy Kuo]

Cut the PC board traces that attach the left and right channel pads to the amplifier circuit. This isolates the socket even when it is soldered back onto the board. The ground is a large area that can't be cut free from the rest of the circuit. Therefore, I simply didn't solder the socket's ground connector back onto the PC board. A thin piece of plastic was placed underneat the ground connector as the socket was resoldered. That leaves the ground contact also isolated.

Recheck the PC board trace cuts that you make. Be sure they are definitely gone and you haven't cut away any other lines!

[Guy Kuo]

The direct out audio signal is carried by the yellow, green, and THIN black wires. Desolder those from the PC board and then tack solder them to the socket's connectors. Be careful not to overheat the ground connector or you might melt your plastic insulator that keeps the ground contact isolated from the PC board ground.

Here is the completed mod with the wires soldered in place. You can't see it because it is transparent, but a small piece of plastic (a piece of the Belkin packaging plastic actually) is under the ground connector.

Put it back together and test your work by connecting the Belkin to your iPod and then attaching your earphone to the output. Even without the Belkin plugged into a lighter socket, you should hear sound from the ipod clearly and quite loudly.

Important!!!! The THIN black wire is the audio ground. Don't use the thicker gray line that is attached to the circuit board between where the yellow and green wires were originally attached. If you use the gray wire instead, you'll get lots of background noise and practically zero bass!

Going to a direct line out connection and bypassing the Belkin amp makes a huge difference in sound clarity. It will probably need a little higher volume setting on your head end, but in my book it was definitely worth all the work. Just go A/B compare using the output of your dock vs the original Belkin sound. If the direct connect sounds better to you, then do the mod. I find that clarify is restored. It always sounded a bit muffled even when loud if the Belkin amp was in between the ipod and the head unit.

BTW, I do use a DC blocker between the head unit and the iPod to ensure against engine noise.

[Jesper]

I'm using the thicker black wire inbetween the green and yellow wire and have had no problems. Bass is coming through fine and it sounds exactly like the Apple Dock.

I was using this picture as a reference (taken from the forums somewhere, but can't find the original post).

http://home.swiftdsl.com.au/~sunnydale/wire.jpg

And it would sorta make sense as the 3 of them (thicker black, yellow and green) all exit from the same sheath in the Belkin.

I did some testing with a multimeter and using the picture below as a reference (from ipoding.com).

http://home.swiftdsl.com.au/~sunnydale/dock.jpg

If I connect the Belkin dock connector to the dock and test for continuity between the lineout return and the ground on the headphone socket there is no continuity. And I checked all the other pins on the dock and none of them provide a connection.

However, if I connect a headphone jack to the lineout on the dock and the lineout of the Belkin, there is a connection between the lineout return (on the dock) and the ground of the headphone jack.

Remembering that I have soldered the thicker black wire we can conclude that:

-The return wire on the dock connects directly to the lineout jack on the dock and does NOT connect to the dock connector at all. (We can probably extrapolate that the Left and Right channels are the same)

-Since no continuity was established between the THICK black wire and any of the pins while connected through the dock connector, we can concluded that the wire is not connected to any of the pins of the dock connector on the dock. This would lead me to believe that it is actually the return audio wire.

I however did not check if any of the other grounds were connected to the dock connector. However, if you have a dock and a multimeter maybe you could try?

Regardless of what actually is happening, I don't think it matters too much as I have read somewhere that all the grounds inside the iPod are summed.

Well tell us what you think of my reasoning, please correct me if I'm wrong. Have you or heard about anyone actually experincing problems using the thicker black wire?

Please don't get me wrong, I'm not making an attack on you or anything. But, I'm after the best sound I can get from my iPod and if there is a problem using the thick black wire then I would like to change it.

[Guy Kuo]

I didn't try the thick black line. It probably is fine just as you describe to use that one instead. It would make the mod easier as there would no longer be a need to isolate the ground connector of the socket.

Just do NOT use the gray wire as the ground. That one will let you hear the disc drive spin up and down and all sorts of other noises.

[obsydion]

Originally posted by Guy Kuo
There is an easier way to do this mod by using an external jack, but I wanted to make it extra neat and simply used the existing jack.

Hey Guy, I am completely useless with electronics and I would prefer not to open up the charger and fiddle around with it. Could you elaborate on the external jack option? :p

[Guy Kuo]

You can see that method at http://www.cruze.org/pics/showdate.html?date=2004-03-13

It still requires you to expose the Belkin's gutlets and do some soldering.

[Guy Kuo]

My next project is to add some components to the Belkin and rewire my remote so that when power comes on the iPod automatically starts playing. I've got a simple circuit composed of a resistor, capacitor and reed relay that should do the trick. I'll report back if it works as expected.

[Jesper]

Guy Kuo that sounds interesting. Definitely keep us posted on how it goes.

[Guy Kuo]

Got the automatic play circuit working. See http://www.ipodlounge.com/forums/showthread.php?s=&postid=276122#post276122

[Dave Wenzlick]

I just did the Belkin Auto Kit Amp Bypass as detailed by Guy. I had a few hours tonight so I decided to test several versions of wiring.

My first test was to leave the ground connection pad on the socket soldered to the board and only move the left and right audio wires to the new location. This caused a noticable hiss in the audio when paused during a song. The hiss was ONLY noticed when the Belkin was receiving power from the cig lighter plug.

The next test was to "float" the ground pad of the socket as suggested by Guy but then solder the thick black line to the socket ground as suggested by Jesper. This resulted in excellent sound and compared directly in quality to using the docking connector to obtain line out with no charging taking place. It makes sense to me to use the thick black line for the audio ground since it is the combined shielding for the left and right audio wires.

The second version was the best and with the iPod in pause and the volume cranked on the head unit, I can detect a slight amount of hiss when the Belkin is charging the iPod compared to when it is not charging. At high listening levels I could not detect any difference. I could only detect the hiss during charging if the audio was set well above where I would ever set it to listen to music. I also tested with the motor running and that was quiet too. This is all without a ground loop isolator.

Your mileage may vary :) as all vehicles and installs have slight variances.

Thanks to Guy for all the detailed photos and Jesper for some tips to try other wires.

Excellent results.

Guy, your Auto-Play mod is next in line.

Dave W.

[Guy Kuo]

I now envy my wife's setup because she has the auto-start circuit. Careful about which contact to connect inside the remote. I have the numbering wrong in the photo caption for forward and reverse, but it is correct in my posted message.

[PagalDesi4Life]

Guy Kuo- I am having some problems after doing this mod. I PM'ed you about the problem. If you didn't recieve it, then I'll post it in here.

-Mehul

[PagalDesi4Life]

Guy Kuo- I am having some problems after doing this mod. I PM'ed you about the problem. If you didn't recieve it, then I'll post it in here.

-Mehul

[Dave Wenzlick]

I did this Belkin mod and the auto-play mod and it works great. I wired the cig lighter outlet, dedicted to the Belkin charger, to my radio power wire which has a delayed-off feature. Now, when I turn off the car, the radio continues to play along with the ipod until I close the last door on the car. The radio and ipod shut down together. At start up, the radio and ipod resume playing where they left off.

Dave W.

[tlpru]

looking for information on the auto-play mod?

thanks
tlpru

[tlpru]

looking for information on the auto-play mod?

thanks
tlpru

[Jesper]

Originally posted by tlpru
looking for information on the auto-play mod?

thanks
tlpru
The link is in the previous page.

[rmoody]

Originally posted by Jesper
The link is in the previous page.

The link does not work.

[Jesper]

http://ipodlounge.com/forums/showthread.php?s=&threadid=46305&highlight=automatic+play

If that doesn't work just do a search with "guy kuo" for the nickname and "automatic play" for the text.

[hansenc]

I did the external mod and hooked everything up and still had a bad hissing sound so i went ahead and bought a ground loop isolator and everything is clear as a bell now :) I couldn't be happier with my ipod install.

[tlpru]

did the mod....
i tried using the larger black ground wire...but.....i get losts of background noise..

will try the smaller black wire.....

if that does not help......will try the ground loop isolator/..

[PagalDesi4Life]

did the mod...

well my friend did it for me actually..

got some background noise, should I try the ground loop isolator or the dc noise filter?

sound works...but the actual charger doesn't not, it won't charge! :eek: What to do now??

[tlpru]

using the small black wire for the ground......the engine noise was VERY loud,....

will use the larger black wire ......with a ground loop isolator...
we will see........

i dont remember having engine noise when i used the charger before the mod.........

[Jesper]

hmm that's weird, don't really know what is going on. Maybe it's possible that the Belkin onboard amp also acts a noise filter? What happens when you don't connect up the power to the Belkin and just use it for it's lineout?

[tlpru]

plays fine with the charger unplugged....
when i plug it in......buzzin,.....

[DrewT]

ground loop then

[DrewT]

ground loop then

[PagalDesi4Life]

Originally posted by tlpru
plays fine with the charger unplugged....
when i plug it in......buzzin,.....

Yea I get that too.

[fretster]

just did this with mine, works great and looks alot better than doing the additional headphone jack! longest amount of time i spent on it was desoldering the jack to remove it from the board, rest of it went smoothly. thanks again!

[rowka]

How does removing the amp effect the line level?
I have a FM modulator with no gain control and have to have the Belkin amp AND my head set for almost max volume to get it to a decent level.

Will there be a significant drop in line level by removing the amp?
If so, what is the "better" option:
1 - Find a 12v line level amp?
2 - Get a new modulator with a gain control?

Thanks

[Dave Wenzlick]

Can you temporarily plug the ipod into the ipod base and use the Line Out phonojack to know what the new level will be after removing the amp from the belkin circuit?

I don't know how much it affects the levels but it certainly cleaned up my audio. I have level adjustment in the head unit after the RCA inputs so I have never used a FM modulator.

[rowka]

Can I do that without having power to the iPod base? Can/Should I connect the charger to the base first?

[Dave Wenzlick]

Yes, as long as the ipod is charged of couse, you will still get line level audio from the small phono jack on the rear of the base. Compare the audio level from that output into your FM modulator as opposed to the audio output when going through the Belkin. It will be lower level but cleaner audio without the Belkin amp inline. You just have to decide if it's too low to compensate down the line without distortion.

[rowka]

Thanks. I'll try that tonight.

[victor_ipod]

Hi, unfortunately I am not very tech-oriented so I was hoping for someone who would like to explain some small questions.

Here they are:
- I am currently connecting my iPod through the ear phones output on top of my iPod to the MD-input of my stereo amplifier but I really have to turn the volume up to get the same volume level as for playing a CD. Even when I turn the volume on my iPod to the max. Will this lack of volume decreases when I connect to my stereo through the iPod dock?
- I have read the marvellous article from Guy Kuo in which he explains how to disconnect the line out from the Belkin Autokit in order to get a direct line-out. When I connect my iPod to my car stereo now (using a 3.5mm cable directly into the aux of my car stereo) I experience the same lack of volume as mentioned above. Again by using the ear phones output of the iPod. More or less the same question; will this improve when I will use the Belkin Autokit?

I hope someone finds the time to explain this to me. Would appreciate it. Thanks, Victor

[Sts10188]

The Autokit will provide a lot stronger of a signal than just the headphone jack. I use to run a cord from the headphone jack to the AUX input of my HU and I had the same low volume problem. I bought the Autokit and it works A LOT better, although I have not done the line out mod. The sound was still lower than a CD, but source level control on my HU solved that.

[bcruze]

Thats probably something do do with the amp the belkin has in it.

[Sts10188]

I finally got aroung to doing this mod and the line out works wonderfully. However, my iPod WILL NOT charge now. I plug it into the socket and the LED lights up, but the ipod does not show power being applied. When I did the mod, I accidentally starting cutting away at the wrong trace, but figured it out before I completely cut it away. I thought I just scrapped the paint off of it because I can still see the metal of the trace, but now, I don't know. The one I wrongly scrapped at is the one directly above the trace that connects to right audio of the jack. Could this be the cause or is something else wrong with it? I doubt I cut the power lead to the charger because the LED still lights.

[houstinojillian]

why not just spice the line out into the cable shortly before it enters the belekin housing? almost as clean, and wouldn't require you to open the belekin housing, just cut a bit of the wire's sheath off, snip the 3 correct wires, and splice away. you could even jeave the wires intact, and splice a line out in, giving yourself the option of using the belkin amp or not (althoguh i wouldn't do it that way).

[bcruze]

Why risk cutting into the power and ground wires when you can just tap the already broken-out wires inside the Belkin case? It's not like it's rocket science taking it apart and putting it back together and it looks much nicer.

[houstinojillian]

would it be possible to do the external line out, but have the cord coming through the premade hole (for the existing stereo jack) as in, could i do all of the line out modifications as if i was doing an external setup, but then also remove the current headphones jack and pass the cord through there? or does removing it for good mess something up?

[Jesper]

Yup that wouldn't be a problem at all. All the circuitry in the Belkin is for the mini-amplifier. All that is required to pause the iPod is a resistor between the white wire and ground.

[houstinojillian]

nice, thats what i'm going to do then, i like the one line out from the belekin, but i also need the cord to be a bit longer... my car sale is going through this weekend so hopefully i'll be able to mount this all in the new car next week!

[danmcg]

Just did this mod. First time I ever have sucessfully soldered something that is small!

I've gone through 2 playstations in the past when I was younger and less patient trying to do circuit work... :rolleyes:

Anyway, I used the big black wire and have no isses with the sound quality at all. Soldered all 4 points back to the board. No hissing or anything.

:D

[danmcg]

Ok so now that I have listened to it at high volumes I am getting noise over the line. It is only happening when the power is plugged in though.

Would a ground loop isolator fix this problem? I guess it would be more of a patch?

What is the "right" way to address this issue?

Thanks!