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Wires in a 3.5mm audio splitter

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jcvamp

Nov 17, 2015
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Hi. I'm going to be wiring an audio splitter into an amplifier board (specifically, this one https://www.adafruit.com/products/2130), but I'm having trouble identifying which wires are which on the audio splitter. The cable has a green and a blue wire grouped together, and a red and an orange wire grouped together. The jack is 4-pole, so I'm assuming the extra pole is for a microphone.

I've included some pictures to illustrate. https://www.dropbox.com/s/c7wlho0sq9fzxar/Audio Splitter.jpg?dl=0 and https://www.dropbox.com/s/7vwigxz7puj70w9/Wires.JPG?dl=0
 

HellasTechn

Apr 14, 2013
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Hi. I'm going to be wiring an audio splitter into an amplifier board (specifically, this one https://www.adafruit.com/products/2130), but I'm having trouble identifying which wires are which on the audio splitter. The cable has a green and a blue wire grouped together, and a red and an orange wire grouped together. The jack is 4-pole, so I'm assuming the extra pole is for a microphone.

I've included some pictures to illustrate. https://www.dropbox.com/s/c7wlho0sq9fzxar/Audio Splitter.jpg?dl=0 and https://www.dropbox.com/s/7vwigxz7puj70w9/Wires.JPG?dl=0

4 pole jacks also include microphone that is correct.

I the wire colour is random i think their is no standard colour code for that. Best way to test it and see what goes where is to use a multimeter like agaibh suggested.

check here :

http://9w2svt.blogspot.gr/2014/08/aprsdroid-audiocable-35mm-4-pin-trrs.html
 

jcvamp

Nov 17, 2015
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I have a multimeter somewhere. Would I test the cable by putting one probe on a section of the jack, and the other on the wires to see which one registers?
 

HellasTechn

Apr 14, 2013
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Yes that is right. Only make sure that the end of the coloured cable is not covered with insulating varnish.
 

Martaine2005

May 12, 2015
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Depending on the age, the mic could be the same as this pic below or or swapped with the GRND.

images


Martin
 

jcvamp

Nov 17, 2015
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I've determine that the tip is blue, ring-1 is red, ring 2 is orange, and green is the sleeve.

I've checked out the configuration of the 4-pole socket on the Raspberry Pi 2 Model B to determine which wires to use. Thanks.
 
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Tha fios agaibh

Aug 11, 2014
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I'm wondering if tying orange with green is warranted to establish a better (low resistance) connection.
I imagine it would work either way although there might be a tiny amount of signal loss, depending on how the jack is constructed.
 

Martaine2005

May 12, 2015
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Well I suppose that would depend on what the OP wants.
If I wanted an audio splitter only, I would use TRS. Maybe he wants to use all 4 wires to keep mic working?
Who knows! Who are we to even question why people do what they do?:p

Martin
 

jcvamp

Nov 17, 2015
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I don't want the mic to function. What I'm doing is building a Raspberry Pi into a Gameboy Advance and I wanted to get audio from the passive speaker that came with the GBA.

I bought an amplifier board that works with the power board I have, and I've soldered wires to supply 5 volts to it. As there is a single speaker, the connection to the Raspberry Pi is going to be mono, so I needed to find the common/ground wire and use either of the audio wires.

I've soldered the right audio and ground, and the speaker is receiving power (as it's hissing quietly), but doesn't seem to be carrying any audio. I'm not sure if it's the speaker or the jack. I'm considering de-soldering the right audio and trying it with the left instead.
 

Martaine2005

May 12, 2015
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Actually John,
I just read that the GBA only has one speaker but is in fact stereo at the headphone out!.
So putting a resistor on L and R and joining them at the mono amp input would solve finding out which is which...
Also that amp has a tiny volume pot too. Put that half way just incase it's low..

Martin
 

Tha fios agaibh

Aug 11, 2014
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Good point. I'm amazed how small and inexpensive they can make this stuff now a days.
My inner geek wants to build an amp with discrete components, but my outer brain says; don't be an idiot, you can buy it for a fraction of the cost.
(....Long sigh)
 

Martaine2005

May 12, 2015
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I am in the process of doing just that! Buying does feel good, but making feels better!!
I never listen to my brain...It lies to me far too often.:confused:

My nephews want external speakers for their tablets and love flashing leds! Who don't?
So I'm making active speakers with 386's and 3914 and 3915's cascaded in dot mode so the boxes look like led cubes in the dark, flashing to music.
It would be far easier to buy something, but why? Much more fun and keeps me out of trouble!!

Martin
 

HellasTechn

Apr 14, 2013
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Good point. I'm amazed how small and inexpensive they can make this stuff now a days.
My inner geek wants to build an amp with discrete components, but my outer brain says; don't be an idiot, you can buy it for a fraction of the cost.
(....Long sigh)

It just doesnt feel the same. You miss the joy of creating something with your own hands !
Why dont you just try making one with SMD ? it will be smaller.
 

Tha fios agaibh

Aug 11, 2014
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Screenshot_2015-11-18-22-03-08-1.png
It just doesnt feel the same. You miss the joy of creating something with your own hands !

Why dont you just try making one with SMD ? it will be smaller.

That's true. My hands are a little unsteady dealing with anything that small but that might be fun.

Of course, small is not always better.

I've got one of these is the family room that does amplification superbly.
 

jcvamp

Nov 17, 2015
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Making if definitely better than buying, partly for the experience, and partly because it allows you to include extra features the original console didn't include, or do something completely different.

Anyway, I tried using the left audio wire instead, and it still didn't play any audio. I ended up looking to see if anyone had soldered directly to the Raspberry Pi 4-Pole solder points. I found this https://learn.adafruit.com/pocket-pigrrl/pi-audio. I followed the instructions, and the audio works.
 
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