Hisssssssssssssss

[ajrobson]

Now that successfully built a new 80GB DMS and have converted all my tunes to flac, I'm afraid I'm still not happy with the overall sound quality of my system.

I have an 04 Passat with Monsoon which has been heavily upgraded. Kenwood and Alpine amps, CDT speakers front and back, custom fiberglass sub-enclosure with 10" JL Audio subwoofer along with a nice Kicker eq. It isn't the most expensive system and it isn't the loudest, but I think it should be able to produce fairly clean and accurate music.

My car before the Passat as a Golf where I had the same CDT two way speakers installed with an amp, eq and Kenwood HU. There was virtually no hiss.

The only thing remaining stock in the Passat is the VW head unit and I am fairly certain it is the source of the hiss. When I turn the volume down, I can still hear it until the volume goes completely "off" and it stops.

In spite of loving my steering wheel controls, I love clean music even more. However, I definately don't want to go down the road of installing a Kenwood HU (my only aftermarket option that will work with my Phatbox after getting the proper cable and flashing the Phatbox again) to only discover that it isn't worth it and it is still hissy.

Will any of the recent Kenwoods that accept CD changers work? My current VW HU is a DBl Din so would like to fill that hole completely.  I could always go with a single din and put the eq in the other hole, but I guess most of the newer Kenwoods do have eq's built in. I'm not really interested in DVD's... but my son might like that.

Anyway.... someone in the Hydrogen Audio forums once told me that since the VW HU is basically a "pre-amp" that can not add noise to the music. I was hoping one of you Phatbox gurus can dispell that.

Thanks.

[judb]

Does the hiss stay constant in level and pitch or does it change like alt whine?

[ajrobson]

It is constant... unless I adjust the eq... which I have set with only a slight boost at the high freqs.  It will get louder also when I increasee the volume when there is no music playing.

And just for fun... I disconnected the input from the HU to the eq and instead connected the output from my iAudio X5 to it instead (also playing .flac) and there is no hiss at all.

So I guess I answered my own question.

Now I just have to decide which Kenwood HU I want. One website I visited showed that the dbl din I was looking at would NOT fit into my Passat.

[sbingner]

Yes, any Kenwood should work fine.


Now, as to the hiss -- I just wanted to make sure you get the same hiss from playing a CD in the HU itself, or playing radio.   If you don't it could be induced on the wires from the phatbox...  if you know anybody with a kenwood HU you could borrow it and see how that works.  Your problem is going to be getting the Kenwood <-> Phatbox cable, it's a real pain to find and it's not much fun to make the cables.   I've made a PhatBox<->Sony cable that works fine, but the kenwood has about 3 times the number of connected wires.  

[ajrobson]

The hiss is the same with the radio, a CD or the Phatbox.

I do know that the VW doesn't have true line level RCA outs and I ended up soldering RCA jacks directly to the outputs that went the speakers (or rather, to the monsoon amp).

I'm wondering if a proper line level to low level converter might help here. But since this head unit was designed to work with an external amp, I suspect that the levels going to that monsoon amp were fairly low as it was. And I didn't have to set the input level for my Infinity and Alpine amps extra low or anything. (It's an Infinity amp, not Kenwood, as I said before.)

But I have no reason to prefer Kenwood over Sony when it comes to choosing a new HU. I am afraid I didn't even realize that Sony worked. So if a Sony will require a less complicated cable, I am all for that.

If possible, I would like to not destroy the cable that is in there now. Thus make some sort of adapter that connects to the HU end of the CD changer cable and then connects to the Sony HU.

[sbingner]

If you can, I'd reccomend the Kenwood over the Sony -- it's just a little harder to fabricate a cable, the actual interface is better with Kenwood.   You could also try to buy a kenwood cable, if you look around you'll find a few places that supposedly sell them but people don't always have much luck buying it.

[sbingner]

Oh, and you will need a new cable --- the pins used for different head units on the PhatBox side are different so you can't do that.   see http://www.phathack.com/index.cgi?page=pinouts for the different cable pinouts

[ajrobson]

I suspected that the Kenwood interface was better... especially if I can get a dbl din to fit.

IF I can find a Kenwood cable, will that fit my current VW Phatbox?  It does look like it will from the picts on that link.

Thanks for your help.

[ajrobson]

Oh, and you will need a new cable --- the pins used for different head units on the PhatBox side are different so you can't do that.   see http://www.phathack.com/index.cgi?page=pinouts for the different cable pinouts

Okay. I still don't understand something here. Those diagrams do show which wires connect to which pin at both ends... Phatbox end and HU end. Why can't I just get a Kenwood end, figure out which wires go where, and then solder it up?  All of those pinout diagrams have the same Phatbox connector in common, so I don't get why it won't work.

[markbowen]

You can save the hassle and just buy the Kenwood cable for 50-60 bucks.  

The part number for the cable is KHD-5L1.  It will connect to the VW Phatbox -- the connections on the Phatbox side are all the same, it is the connection on the HU side that is different.

The cable is listed in stock at all of these websites:
http://www.partstore.com/ProductDetail.aspx?ProductSKU=3183622&s=sspro ($60)
http://www.hermanelectronics.com/ItemInfo.asp?Frecno=4573891 ($55)
http://www.pacparts.com ($50) - search by part number KHD-5L1
http://www.kenwoodparts.com ($50) - search by part number KHD-5L1

Also, if you want to keep your steering wheel controls, most Kenwood HUs can receive infrared commands.  If you know a good "ride pimper," there is probably some way to rig the guts from a Kenwood handheld or steering wheel remote to work from your stock steering wheel controls.

[S80_UK]

Oh, and you will need a new cable --- the pins used for different head units on the PhatBox side are different so you can't do that.   see http://www.phathack.com/index.cgi?page=pinouts for the different cable pinouts

Okay. I still don't understand something here. Those diagrams do show which wires connect to which pin at both ends... Phatbox end and HU end. Why can't I just get a Kenwood end, figure out which wires go where, and then solder it up?  All of those pinout diagrams have the same Phatbox connector in common, so I don't get why it won't work.

Hi.  The reason is that different firmwares for different HUs use completely different signals on the pins at the PB end of the cable.  The pins for power and audio don't change, but the various signal lines move around quite a lot.  So a VW PB cable cannot simply be spliced onto a cable for a Kenwood HU, or any other HU for that matter.

Kenwood uses pins 8, 9, 11, 12, 17, 22, and 24 for control purposes.  VW uses 12, 14, 24 and 25, so the PB connector supplied at the end of the VW cable does not even have all the wires that are needed soldered to the pins.  I know, I cut one up in the early days to get a connector!

If you do end up making your own cable, connectors compatible with the PB are available in the US from suppliers such as Digikey, and from RS Components in Europe (there are posts on the form with the details).

Good luck.

[sbingner]

Right, if you get a kenwood cd changer cable you could probably buy the phatbox end and put it on... if you can get a pre-fab cable from the links above it's your best bet tho

[ajrobson]

Kenwood uses pins 8, 9, 11, 12, 17, 22, and 24 for control purposes.  VW uses 12, 14, 24 and 25, so the PB connector supplied at the end of the VW cable does not even have all the wires that are needed soldered to the pins.  I know, I cut one up in the early days to get a connector!

If you do end up making your own cable, connectors compatible with the PB are available in the US from suppliers such as Digikey, and from RS Components in Europe (there are posts on the form with the details).

Good luck.

Okay... NOW I understand. I just figured ALL the pin were used in the cables... but when one really thinks about it, why would they use a cable with extra and unused wires... that would cost them money.

Is the same true for the VW CD changer cable that was in my car when I bought it? Or does that only hold for the adapter piece that connects the CD changer cable to the Phatbox?  I suspect that it does.  

It isn't that I mind buying a pre-fab cable, it just might be hard to find one. (tho I did come across some website the other day that listed the cable and it appeared to be in stock).

[S80_UK]

If you can, I'd advise that you go for the ready made cable.  That way, if ever you don't want it, you will at least be able to sell it and recover some of the cost.  Sorry - I can't comment on the VW CD cables - I don't have a VW.

[sbingner]

According to my pinouts: The VW connection has 9 separate lines.  The Kenwood connection has 12 separate lines.   That means that unless they just threw extra cables into your CD changer cable running to the trunk for the hell of it you can't run the 12 separate wires required for kenwood over the 9 required for a VW.

[ajrobson]

The hiss now isn't so bad.  

This is because I have converted all my music to flac and the quality is so much better that I have been able to lower the high end boost on my EQ with the hiss now being much more tolerable.

[indianajones]

The hissing is a known issue on passats and some other VWs. The problem is caused by a ground loop and here is a solution for this problem:

http://www.passatworld.com/forums/showthread.php?t=225338

I am just building my own cable with a ground loop isolator from Radio Shack. Not going to worry about adding a line filter. Should be enough to stop the hissing sound.

[S80_UK]

I am just building my own cable with a ground loop isolator from Radio Shack. Not going to worry about adding a line filter. Should be enough to stop the hissing sound.

This is exactly what I did for my Volvo - and it has been perfect ever since.  I am sure you will notice a huge difference with this enhancement.

[indianajones]

Finished my cable.....

Uaaaaaaaaaaaaaaaaaaaa.... what a difference...  
No hissing sound whatsoever. I really recommend everybody just getting a ground loop isolator from Radio Shack and building their own 1 foot cable and connect it between the phatbox and the stereo unit.

[ajrobson]

Wow.

I just saw the response about the ground loop issue. At the moment the Passatworld link doesn't work. Does anyone know if that site is permanently down?

Or can someone give me some tips on installing the ground loop isolator (i.e. which wires)?

I really don't want to go to a different head unit as I like the steering wheels track and volume controls. And as my car doesn't live in a garage, I don't really wanna give any theives any reason to break in.

Okay... after a bit more Googling, I have found this thread over at mp3car.com:  http://www.mp3car.com/vbulletin/showthread.php?t=63879

partway down the page there is a picture of a Radio Shack ground loop isolator: Radio Shack GLI (part #270-054), price $16.99.

As I have an equalizer mounted in my center armrest console, installing one of these will be a piece of cake.

But before I give it a shot it would be terrific if someone could confirm that is the part (or one like it) that I need??

Thanks.

Btw... tonight after loading some new songs to my 80gb hacked DMS I received the dreaded "No Disc" warning after inserting the stupid thing. After a bit of searching this forum I tried just disconnecting and reconnecting the cable to the Phatbox and it worked just fine.

This forum is the most useful one I have ever used. Thank you all.