I know a few others have been using the 7135 to play MP3s via the car stereo. Using the CoolCat adapter I have connected the 7135 to an aux input in my VW's car stereo (aux input is in the trunk and is meant for a 6 pack CD changer). I have also wired in a mic and created a poor-mans handsfree kit.
I have run into a strange low-frequency electronic sound coming from the 7135 and I'm wondering if anyone knows how to eliminate it. The sound is best described as a helicopter and modem high tone mixed. The noise is present as soon as the 7135 adapter is connected and plays through the right channel only. Interestingly, as soon as MP3s begin to play, the sound goes away, but comes back in the pause between tracks.
I have eliminated my car stereo or the wiring I installed as the cause of this sound. If I use the CoolCat and plug the 7135 into other powered speakers or into my home stereo amp, the low frequency sound is also present. The more powerful the amplifier, the louder the sound (i.e. it is harder to hear through powered speakers than through the car stereo, and not audible with a headset).
I've also confirmed that other 7135s emit this sound as I've tested 3 other units in the car, and via powered speakers and all demonstrate the same low frequency noise. Anyone have any idea what may be causing this sound and how to eliminate it?
Sounds like a floating ground problem in the connection, or maybe the impedence is not right for going from the 7135 to the AUX connector. Have you tried it with a cassette adapter hooked to the 7135, or an FM modulator ??
Yes, I've tried it with an FM modulator and the noise is certainly there -- initially, I thought it was a problem with the FM modulator, but now that I've hard wired the unit, I've ruled that out.
Per my earlier note, I've ruled out any problems with the car audio system or my wiring job as my 7135 and the 2 other 7135s that I've tested also emit this noise when plugged into a home stereo or powered speakers.
If the sound goes away when an MP3 is playing then I doubt that there's anything wrong with the adapter. A problem would either be constant or randomly intermittent if there were a problem with the adapter. I've noticed weird noises coming from the 7135's headset jack when its not doing anything (not from the jack itself, but through a headset or adapter plugged into it). I think its just a quirk of the phone.
Later,
Cool Cat
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Sorry, but I no longer make 7135 headset adapters.
Yeah, I have confirmed what you are saying. I frigged around some more and tested the phone without the adapter and the noise is still there.
I'm wondering if the noise is some form of induction from the CPU and other electronics that would not be noticed until it is amplified through a car or home stereo.
Anyhow, this problem appears to be a phone quirk -- bothersome, but not a show stopper.
I've noticed the same spurious sound. It's only audible on the right channel, and its fast pulsation resembles the beating of helicopter blades. To me, it sounds more like a Martian ray gun in a sci-fi movie.
However, I only hear it when the signal is amplified and the MP3 player is NOT playing. I use Boostaroo to enhance my audio output, and only then do I hear the sound that you describe. When the MP3 resumes playing, the sound disappears.
At first, I thought this was some type of electrical mismatch between the phone and the Boostaroo, or some type of noise originating in the Boostaroo. Now, I'd say that it's more likely to be a systemic characteristic (or flaw, if you prefer) of the Kyocera 7135. Normally inaudible, this sound becomes audible when you amplify the sound, either through your car stereo's amplifier or by my Boostaroo mini-amplifier.
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