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Topic: How to read data from audio jack? (Read 469 times) previous topic - next topic

kitce

No, looks good to me.
Great.

So with this circuit, I could get the value from 0-1023 for the loudness of the right channel from the audio jack?

Also, I am wondering do I really need to connect the ground of the audio jack?

If I need the left channel in the future, is it okay to just do the same circuit as the right channel and input to another analog pin?

Grumpy_Mike

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So with this circuit, I could get the value from 0-1023 for the loudness of the right channel from the audio jack?
Yes, providing there is no DC component to the output from the amplifier. If there is you need a seriese capacitor between the diode and the jack.

Yes you do need to connect the ground of a jack, any voltage is measured as a difference between two points, without the ground connection you don't have two points.

Yes another circuit will work just the same.

kitce

Yes, providing there is no DC component to the output from the amplifier. If there is you need a seriese capacitor between the diode and the jack.

Yes you do need to connect the ground of a jack, any voltage is measured as a difference between two points, without the ground connection you don't have two points.

Yes another circuit will work just the same.
Do you mean the audio jack of the USB DAC? I am not sure about what is DC component.
The audio jack is available for any earphones/headphones/speakers with 3.5mm audio connector, I think its signal is same as those of the smartphones/media players .

Grumpy_Mike

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Do you mean the audio jack of the USB DAC?
Please supply a link to this.

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I am not sure about what is DC component.
https://forum.allaboutcircuits.com/threads/what-is-the-dc-component.7210/


kitce

Please supply a link to this.
https://forum.allaboutcircuits.com/threads/what-is-the-dc-component.7210/


Here you are:
http://www.ebay.com/itm/BlueBird-DAC3-0-CS4398-CS8416-SA9023-USB-DAC-Decorder-headphone-amplifier-/112053201337?_ul=GT

Output:
   3.5jack headphone output on back panel, directly drived by decoder chip modul
   6.5jack headphone output on front panel, drived by headphone amplification extend card
   analog output

I will be reading the signal from the 3.5mm jack.

Grumpy_Mike

Thanks.

I think it is the French translation that ends up using words that we would not use in English to describe things.

kitce

#21
May 14, 2017, 03:47 pm Last Edit: May 14, 2017, 03:53 pm by kitce
Thanks.

I think it is the French translation that ends up using words that we would not use in English to describe things.
I see the item description is in English. Anyway, I copied the description below:
and this link has more details and photos.
http://www.ebay.com/itm/Bluebird-DAC3-0-CS4398-CS8416-SA9023-USB-DAC-descodificador-Amplificador-Para-Auriculares-/112053201337?_ul=GT&nma=true&si=VmIFKsY6%252BRduQRSPa6FFEOI2%252Fgo%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
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For the same decoding chip, different filter circuit is one of the biggest influence. Bluebird uses its own independent development of filter circuit. Make sound more natural,clean,downy.
Specification:
Size: 22cm*5cm*12.5cm
Weight: 1.2Kg
Support the sampling rate:
    Coaxial 24B 192K
    Optical fiber 24B 192K
    USB   24B 96K (XP,WIN7, WIN8. MAC driving free ,support mobile OTG decoding)
Decoding chip: CS4398+CS8416+SA9023
Headphone power: 460MW/32ohms
Input:  USB/Coaxial/Optical or Analog input, Use back panel's switch button to switch betweenUSB/Coaxial/Optical input and Analog input
Output:
   3.5jack headphone output on back panel, directly drived by decoder chip modul
   6.5jack headphone output on front panel, drived by headphone amplification extend card
   analog output

Notice :Look at picture of back part
Back panel left switcher is used to switch between USB/Coaxial/Optical input and Analog input
NC to reserve space. This interface without any function.
COA RCA socket for external coaxial input interface. Support maximum 24 b 192 k sampling rate digital signal input
OPT for external optical fiber input interface.Support maximum 24 b 192 k sampling rate digital signal input
USB to the computer USB port.Computer signal can be directly converted into a maximum 24 b 96 k input to decoding part.To optimize the output.
The decoder part's op-amps use three American big SNE5532 OPA. OPA adopts the plug type design you can freely change. Ascension decoder sound quality. Decoder op-amp adopts dual op-amp. So when you buy upgrade op-amp, pay attention to buy dual op-amp
Headphone amplifier card use two American SNE5534 single op-amp, It's not same with decoding part .You should pay attention to. The op-amp is still adopted plug type design.
The machine adopts full shield square transformer. Reduce interference. Improve signal-to-noise ratio.

kitce

Thank you Mike.

I have successfully built the circuit and the overall result looks good.

But the highest volume value is only about 220, when left and right channels send signal at the same time, the volume from the right channel is even lower.

Therefore, I use the left channel only for the best result now.

DVDdoug

#23
May 16, 2017, 12:03 am Last Edit: May 16, 2017, 12:23 am by DVDdoug
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But the highest volume value is only about 220
That seems about right.   If 1023 is 5V then 222 is about 1V.   If there's a series diode, you're getting a ~0.6V drop across the diode so your audio signal is ~1.6V peak (3.2V peak-to-peak).    That should be a fairly loud headphone signal.

You can try switching to the optional 1.1V internal reference.

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when left and right channels send signal at the same time, the volume from the right channel is even lower.
Of course the left & right channels should be approximately equal and you can check that with headphones.

Don't "short" the left & right channels together.  That can potentially damage the DAC/headphone amp and it will probably "damage" the signal.   If you need both channels you can build another identical circuit and use a 2nd Arduino analog input.  Then if you don't need independent left/right signals you can sum the two channels in software. 

Or, you can make a passive "mixer" with a couple more resistors to mix the left & right signals together through resistors.

Grumpy_Mike

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But the highest volume value is only about 220,
So you need to either turn up the volume or make an amplifier.

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