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Problem with audio jack when connected to stereo via AUX

asked 2013-12-30 10:04:29 +0300

J_W_PEPPER gravatar image

updated 2013-12-30 15:31:58 +0300

pnuu gravatar image

No problems when using headphones, but if phone is connected to stereo system with 3,5mm/RCA extension I get a low frequency buzz which is quite audible. No problems with other players when using the same configuration (iPod, computer etc.)

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1

Is the phone connected to its charger at the same time

rsainio ( 2013-12-30 10:27:53 +0300 )edit

Nope! Granted, it sounds a bit like grounding buzz. Tried with an external mono speaker and no problems there. Someone else had a similar issue when connecting to car stereo (link in finnish) here

J_W_PEPPER ( 2013-12-30 10:54:37 +0300 )edit

I'll add to this that I was using the stock media player and FLAC audio file for playback. Haven't actually tried it again after the "Maadajävri" update. Will do so today.

J_W_PEPPER ( 2013-12-30 11:41:21 +0300 )edit

Oh and I was afraid it might be just my phone. Yes, same here, headphones seem to be fine, car audio has very bad distortion going on, with the stock player as well as android GoneMad Player. Tried two different cables, same result, though it seemed that by turning the plug in the jack resulted in different kinds of distortion, one instance of really really quiet sound and on one occasion actually distortion-free, fine audio. I am swamped with work, so I couldn't test this more.

Ozymandias ( 2013-12-30 14:17:43 +0300 )edit

Tested it again, same setup: not connected to charger, only 3,5 mm to aux extension, same result. The frequency was higher than I remembered. White noise, like a detuned radio. Tried turning the plug like Ozymandias, but no difference. Only some loud pops and contact noise.

J_W_PEPPER ( 2013-12-30 19:21:46 +0300 )edit

6 Answers

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answered 2015-09-08 19:02:38 +0300

hetas gravatar image

Old thread but I'll post my workaround anyway. I've been using Jolla in my car stereo using the aux connector. I've had this distortion problem and it's quite annoying.

I finally found a reasonably priced portable headphone amplifier from Creative. It's an extra device and cables in the car but seems to work. No more crackles.

I got mine from finnish e-shop jimms.fi for 40€. Battery can be charged with similar usb-cable as the phone. There's probably similar devices from different manufacturers.

(Actually the device I got was the E3 even though I ordered E1. So my experiences are based on that. E3 has bluetooth but I don't' use that at the moment. E1 could have been actually better for me. Power and volume buttons seem more practical in the cheaper model. But I'll keep the bluetooth model just in case.)

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answered 2015-09-09 02:15:41 +0300

simo gravatar image

Jolla has an audio jack designed for headphones, not a line out designed for amplifiers. I don't know the exact values on Jolla, but typically headphone jack has a low (8-32 ohm) impedance, compared to hundreds (100-600 ohm) in a line out connector.

  • Headphone jack to headphones: Few ohms impedance from the source is driving few ohms headphones. Matched impedance values are the best for the battery life. Professional headphones have some more impedance, typically resulting as better sound quality but lower max volume.
  • Line out to amplifier: Few hundreds of ohms impedance (line out) is driving 10000 ohms input (line in). The idea is to drop the load to minimum, delivering an easy signal just strong enough to measure to pressures (voltage difference), and amplify that (add more load) in the destination.
  • Headphone jack to amplifier: Low impedance in the source meeting high impedance on the destination reduces the frequency response, tailored in the phone for matched (or closed to matched) impedance. Additionally, compared to line out, headphone jack has it's own noise coming from the headphone amplifier chip and the volume control. Even worse, mobile phone provides very low Vpp (peak to peak voltage), making measuring the pressure a challenge to the amplifier. Depending on the quality of the amplifier, it's own noise might become audible, especially if the volume needs to be set high. In the end, there might be three different quality reductions, in the worst case resulting as low bass not audible and noise added from both the source and the amp.

If the amplifier is a quality one, I'd try with 1/3 - 1/2 volume setting on Jolla (to reduce the signal noise to minimum) and higher volume setting on the amplifier.

If the amplifier is a low-end (car stereo), I'd suggest adding resistors (maybe 600 ohm serial, 100 ohm paraller) into the wire to get closer to typical line out impedance levels, aiming for a signal that the car stereo amplifier is designed for. Sound quality gets better, but notify very low max volume. Powerful amp required.

The best solution: Get a car stereo with Bluetooth audio. Digital signal doesn't mind the impedance ;)

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I got an FM Transmitter. Happy now.

lispy ( 2015-09-09 09:16:33 +0300 )edit

Than you for the details. Makes sense.

hetas ( 2015-09-09 21:07:46 +0300 )edit
1

answered 2014-01-12 13:43:02 +0300

fl gravatar image

From your description of the sounds I am not sure if this might be the case, but it could match.

Please note, that there are two different standards for connecting headsets via 3.5mm.

http://en.wikipedia.org/wiki/AHJ

and

http://en.wikipedia.org/wiki/OMTP

For example N900 and N9 both use OMTP, while Jolla (according to https://twitter.com/phlixi/status/412897182795055104) and most other devices today, like Galaxy / iPhone etc use AHJ.

When I use the original N9 Headset on e. g. a Galaxy Nexus, I get sounds, that could match your description. Fix: use AHJ connector.

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I don't think that's the problem here. The headphones I tested are standard stereo headphones with only three 'bands' on the plug (L/R/Ground) - they work fine. The connecting cables to the car stereo are the exact same. They have the strange distortion. (Although I haven't tested it in a while, haven't had the time. Maybe it's better now or maybe it was just a problem with that specific cable.)

Edit: Just did a quick test at home pluging my Jolla into my Zoom H4, didn't notice any Distortion. Will have to try again with the car stereo.

Ozymandias ( 2014-01-12 14:23:41 +0300 )edit

What Fl is saying I can partially confirm. My N9 headphones isn't working properly, it gives a buzz. A Lumia800 headset works fine.

BonoNL ( 2014-01-27 22:35:23 +0300 )edit

Well of course it's true, I just don't think it has anything to do with the audio connection via normal audio cable.

Ozymandias ( 2014-01-28 11:16:42 +0300 )edit
1

answered 2014-10-20 21:48:18 +0300

updated 2014-10-21 00:02:43 +0300

I've found a workaround for the issue. The problem seems to be the too high input impedance of the AUX-device. Headphones normally have a lower impedance.

You need a splitter cable similar to this that allows to connect two devices to the phone. (EDIT: take attention that it's not a cable that splits the left and the right channel, both female connectors need the left AND the right channel!)

In one output you plug your AUX-device, in the other you plug your earphones. The earphones are now parallel connected to the AUX-device and pulling down the impedance.

Alternatively you can solder yourself a small plug with resistors to pull down the impedance, that way the headphones don't need to be connected. (I haven't tried this yet and I don't know what resistance to choose but it should work too)

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Today I tried the workaround in my car where the noise is extremely loud. There the headphones reduced the noise when parallel connected but didn't eliminated it. When I have more time I will try with different resistors as described above.

scharelc ( 2014-10-21 21:07:14 +0300 )edit

Could something like this help? http://www.amazon.com/3-5mm-Stereo-Patch-Cable-Resistors/dp/B004M49I26.

(I commented on the original question earlier by mistake. I ment the comment about plugs for sale for this answer.)

hetas ( 2014-10-21 22:12:15 +0300 )edit

I don't know how the resistors are inserted in this cable, it could work but there's absolutely no guarantee

scharelc ( 2014-10-21 22:21:39 +0300 )edit
0

answered 2014-10-03 08:50:05 +0300

Sanjay Mehta gravatar image

Your cable could be picking up ambient electrical noise. Try using a shielded audio cable.

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answered 2017-10-27 13:28:04 +0300

MJ2017 gravatar image

This is a old post, but still thought of adding my comment. I have similar problem while connecting audio out from my Samsung Galaxy Note smartphone to Onkyo receiver which is from pre-smartphone era. Smartphone 3.5mm jack pin has 4 sections left, right channel, ground & microphone while the audio jack connected to Onkyo aux In has only 3 sections left, right channel & ground which inserting Onkyo aux In jack into smart phone to great extend it interfere with ground and mic connection which explains why if you turn the jack it works & attimes it doesnt. The solution I contemplate is to cut a smartphone ear phone near its ear piece, discarding mic wire and soldering rest left, right, ground to a 3.5mm female jack receiver with 3 pins only where Aux In jack sbould work like champ.

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For less than £5 or €5 delivered to your door, a new suitable 3.5mm jack to phono (red and white) would surely be a better bet.....for a quick example but perhaps not the best;

https://www.ebay.co.uk/sch/i.html?_nkw=180647598969

FWIW; my amp is a Kenwood home cinema amp from 1991 (still going strong!) but works fine with my Jolla and a standard 3.5mm jack to phono.

Edz ( 2017-10-27 13:41:29 +0300 )edit
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Asked: 2013-12-30 10:04:29 +0300

Seen: 64,629 times

Last updated: Oct 27 '17