Scosche passport causing hissing

I'm having this same exact issue, worked fine on all previous iPhones/iPods, high pitched hiss on 4S. Problem goes away when I remove Scosche passPORT - Charging adapter.

I've got the same issue in my car. I used the Schosche passport for the last few years going from my 3GS into my head unit that uses the original iPod connector- all with no issues whatsoever. Last week I upgrade to the 4S and now it's ground loop noise like crazy. I did some research and I guess that the PassPort was only good for the 3GS not the 4S. Looks like based on Amazon reviews for the passport others have switched to the Cablejive DockStubz converter and are seeing good results with their 4S's. I'm considering buying one, but want to make sure it's the right move first. Anyone out there had success with the 4S docked into their car head unit using the Cablejive converter with NO hissing??

I work for CableJive, we've had many customers order the DockStubz to resolve this issue and have confirmation from customers that there is no hissing/static when using the DockStubz with the 4S.

I ordered CableJive DockStubz and it works great with my 4S in my 08 Scion tC, very clean audio. I think the volume output just may be better too, it seems like I'm not having to put my stereo's volume as high, and thus, not getting blasted when I switch back to the FM Tuner. Also, when I removed iPhone previously, with the Schosche, the stereo would think the iPhone was still connected until I removed the adapter itself, which was very annoying, this doesn't happen anymore, added bonus!

CableJive support was great too, confirmed via a quick email conversation that I shouldn't have any issues before I made the purchase, as they had tested it with a 4S in the office, and they also guaranteed they'd take it back if for some reason it didn't solve the problem with my particular setup.

Ditto to the problem - but it is not isolated to the 4S, it is just loudest with the 4s. I had the same hissing sound with my 3rd Generation iPod touch - but it was much softer and only heard when I needed to turn up the volume for certain podcasts - the pitch and the pattern of the hiss were the same.

I just checked three Scosche chargers - I had one for each car and just bought a 3rd when I thought the hissing sound was because the second one broke. All three produced the hissing sound.

I checked three different iPods - I tried my iPod nano (which yes, I now have to return) and no hissing. iPod Touch 3rd gen - hissing, but much softer. iPod touch - loud hissing.

I checked three different stereos - two car stereos - both had the hissing sound. I also checked an old small clock radio that had an iPod adapter - no hissing sound. So it looks like the hissing is only with certain types of stereso.

I will call the Scosche company tomorrow and see what they say. But looks like I will be purchasing the CableJive DockStubz.