Apple iPhone - auxiliary audio output: NOT car audio
I have a question about connecting my 3GS iPhone to any radio or stereo with an auxiliary input.
When connecting with many stereos, I get a constant, rhythmic pop-pop-popping noise. Sometimes I can fidget with the connection at one end or the other and make it go away, but not always.
FYI, the connection with the input in my Camry Hybrid works with no trouble like this at all.
I'm using different cables in all locations. In my car, it's the white cable that came with the phone (or with an older iPod, maybe). The other cables are aftermarket cables picked up from Radio Shack.
iPhone radio
It sounds like a ground loop to me. Redundant ground connection - somewhere. Are you using a car charger as well? If so, unplug the charger and see if the problem goes away.
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Take the known good cable from the car and try it where you are having the problem, and try the questionable one in the car. See if the problem moves, eliminate the cable from equation.
This could be interference caused by the cell phone. Mine is set for a minimum apps to access Push data and with some radios I hear static about every 15-20 minutes.
If it were the phone itself, the GSM interference would happen regardless of whether the phone was plugged into something or not.
That happens with mere proximity to unshielded speakers.
I'm guessing that the phone is almost always plugged in when in the car (that's what I was doing when I had one and do now with my iTouch), but is it always plugged in when near those other stereos?
If not, then if the same noise happens while not attached, that will eliminate the cabling.
Another question for the OP: Before, you said you were using the AUX input on the stereo, which lead me to assume you are using the headphone jack of the iPhone, but your answer to the question indicates that you're using the dock connector which means using a USB connection. Please clarify which is being used.'
So far as I know, if you're using the dock connector to a USB port, then it is highly unlikely to be a cabling issue.
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Replying to all in an effort to reach some clarity...
1: I'm using a stereo connecting wire, run from the headphone jack on the iPhone to a similar jack in my car. The white cable I'm using for this connection is trouble-free.
2. The phone is never plugged in to a power source or charger during these operations.
3. I took the white cable from my car and used it to connect my iPhone to a stereo in my home, and got the same constant clicking noise.
4. The cables I've tried to use for connecting to home stereo equipment and radios are clearly of varying quality, but they all produce this noise. (I'd found a cheapy cable, and before testing it, thought I'd buy a couple others to just install in stereos and radios and just leave for future use, rather than moving one cable around. I also carry one in my briefcase)
5. The sound can be better described as a pulsation, audible at a constant rate, approximately two clicks per second. I can hear the music I'm playing, but the pulsation renders the audio unlistenable.
I'm still looking for ideas.
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Try putting your phone into airplane mode and see if that fixes it. If so it is the cell tower signal getting into the audio cable.
The solution would be to get a shielded audio cable.
