# Do Media Player's (built-in) DAC impact on the soundquality of attached external USB-Dac's??



## rdlproyectos (Jul 25, 2013)

Hi Folks!

This is my first Thread, if this should have been posted in another place please don' be rude addle:

Last year, with the introduction of a new Feature in Android-based Phones and Tablets, called USB Audio (the ability to redirect the digital stream of the Music playing through the USB port of the Device to the external DAC, in opposition of directing it to the Speaker or Headphone Jack) started large discussions and many Threads in related Forums...

Sooner or later I jumped into it and since then have been using my Samsung GT-I9300 S3 Phone through Usb-Audio, with a Behringer UCA202 USB DAC and a Sennheiser HD 202 Headphone for a time now (Great Sonics btw!). 

So... :scratch:

I was wondering if the internal DAC of the Phone (or the DAC contained in any other Media Player that has the USB Audio feature enabled) has or not Impact in Sound Quality if conected in the above described way, so I can replace it with a cheaper Phone (or better a Tablet), leaving me enough cash for upgrading my Headphones...:sn:

Reason I ask is:

the phone (I believe) acts as a Music transport, the decoding happens into the (external) USB-Dac, AFTER the Music Stream left the phone, *am I right?*

*IF SO, there should be no reason to invest in a costly Phone...*only a basic Android one (if you don't mind High-tech features) 

RIGHT OR WRONG?

Any Input appreciated (especially technically minded ones) :help:


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## Almadacr (May 5, 2011)

IMO the biggest impact will be the quality of the mp3's that you will put on your phone not the phone DAC or external DAC . Some will say that they hear differences but if there life depend on it they could't differentiate between A and B .


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## imazed (Nov 30, 2010)

If you follow this link http://source.android.com/accessories/aoa2.html and scroll down to the Audio Support section. You will see that the USB port outputs a PCM data stream. In other words the Phone DAC is bypassed.
Hope that helps


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## rdlproyectos (Jul 25, 2013)

Almadacr said:


> IMO the biggest impact will be the quality of the mp3's that you will put on your phone not the phone DAC or external DAC . Some will say that they hear differences but if there life depend on it they could't differentiate between A and B .


Sorry, lost track and didn't answer in time: I do not hear mp3's, only flac + wav. Anyway, You are right about the quality of the Mp3's and their impact!


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## rdlproyectos (Jul 25, 2013)

imazed said:


> If you follow this link http://source.android.com/accessories/aoa2.html and scroll down to the Audio Support section. You will see that the USB port outputs a PCM data stream. In other words the Phone DAC is bypassed.
> Hope that helps


Thank You for the input! That's what i read too (in another Site) but strangely, it is not what I have experienced comparing the Usb-audio out from my Phone against a well known Tablet: both use the same Gear, but certainly the Phone has better Sonics than the Tab! 

I guess the DAC isn't bypassed after all :rolleyesno:
cheers
Dan


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## imazed (Nov 30, 2010)

I am a little confused. 
My understanding was that you were checking whether the internal DAC was being bypassed on your Samsung phone which it should, and also seems to be the case as your phone setup has better sonics than the tablet.
I think you need to say which "well known tablet" as the information in the link I previously posted is for Android O/S only. If by well known you mean Apple then the information in the link is not relevant.
Are you now trying to select a tablet which has Android O/S?


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## rdlproyectos (Jul 25, 2013)

imazed said:


> I am a little confused.
> My understanding was that you were checking whether the internal DAC was being bypassed on your Samsung phone which it should, and also seems to be the case as your phone setup has better sonics than the tablet.
> I think you need to say which "well known tablet" as the information in the link I previously posted is for Android O/S only. If by well known you mean Apple then the information in the link is not relevant.
> Are you now trying to select a tablet which has Android O/S?


Sorry if I wasn't clear enough imazed...
I was using BOTH to check their Sonic cappabilities: a Samsung S3 Phone (international version, which has a Wolfson Audio Codec) and a Google Nexus 7 (2012) 3g Tablet, both outputing the Digital Stream thru the USB Audio feature (enabled with a Custom Rom), interconected with a Behringer UCA202 DAC to my Hometheater; Unless I did something wrong down the Road, Comparing both, the Samsung had that "sparkle" that Higher-end audio equipment provide, in contrast of a more "normal" sound I could hear from the Tablet (in the same set-up)...I could be wrong, but that was what I could hear (and feel)...

After You last Post, I found another Site confirming that the internal DAC is bypassed with the USB Audio feature: so now its my turn to shake Heads :dontknow:
I remember reading somewhere (sorry, don't remember where) that the music stream that comes out thru the micro-USB jack could be either digital or analog: sounds weird, right? :sneeky: Do you know (or read) something about it? 

Nevertheless I already sold my Phone because the Plan was to replace my Car Head Unit, with a Tablet (the later gives me aditional Features, like using a Backup Camera, GPS Maps and so on ) linked with the DAC to my Amplifiers to compete my Sound System.

But I can't shake the feeling I am missing Quality (sound-wise) witout the Phone :blink:
later
Dan


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## imazed (Nov 30, 2010)

Dan,
First of all re. your comment:
"I remember reading somewhere (sorry, don't remember where) that the music stream that comes out thru the micro-USB jack could be either digital or analog"
- it HAS to be digital that is coming out of your tablet or the Behringer would not output anything.
I know nothing about the Nexus tablet so , assuming that the tablet does nothing to your Flac file other than play them through the USB, the only explanation can be that the player is causing the problem.
Like you I only listen to Flac and play back using UCA202. Input to the UCA202 is from the USB on my laptop using VLC. I have tried using many different players and find they change the sound quality. I chose VLC because that is what sounds best to me. 
I have not bothered to find an explanation I just trust my ears on what is best for me.


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## rdlproyectos (Jul 25, 2013)

imazed said:


> Dan...it HAS to be digital that is coming out of your tablet or the Behringer would not output anything.


I hope it is! (otherwise, you surely know sonic degradation is likely to happen, because the musical stream that goes from the Tablet to the Behringer DAC and later to a (Car) DSP will suffer Quality loss quite surely :sad: )



imazed said:


> I know nothing about the Nexus tablet so , assuming that the tablet does nothing to your Flac file other than play them through the USB, the only explanation can be that the player is causing the problem.


The Player COULD be the Problem, I am using the one that came with the Mod I have installed...I will try another one and we'll see...As a side note, I don't play Flac's, only Wavs.

Sorry about the late Response (I lose track of my threads quite frecuently lddude: ) and TY for your Time!
Cheers :wave:
Dan


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