Android phones and USB DACs

hold on, I can still control the volume via the SIII, has the signal bypassed the amp section in the phone???

Quote:

peterpenhk said:

hold on, I can still control the volume via the SIII, has the signal bypassed the amp section in the phone???

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mm that will be possible, but one of 2 things may be happening, 1 it may be using digital volume control on the device, which means you will lose bits and thus a loss of quality if it is not on 100%, or 2, which some DACs do, the DAC is hijacking the system volume control, so it works just like normal but is actually being handled in the device.
 
There is an issue with the RSA predator, the DAC is USB powered, just like the ODAC, so you are at the mercy of the S3's 100mW limit, it would help all of us if you contacted RSA and asked how much power the DAC section needs to run properly, and then USB power as we have figured is notoriously dirty, which will hammer the SQ again. 
 
For portable USB audio devices for android and such, it seems its imperative that the DAC/AMP powers itself for best SQ.

Quote:

peterpenhk said:

Just purchased a usb otg cable today and tried out with my RSA predator, works without any problem.
What a suprise! the sound quality actually upgraded, from iPod classic + Predator(amp only) to SIII + Predator(DAC/amp)

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I'dbe very interested to know which USB cable you bought.

Quote:

wir3d said:

mm that will be possible, but one of 2 things may be happening, 1 it may be using digital volume control on the device, which means you will lose bits and thus a loss of quality if it is not on 100%, or 2, which some DACs do, the DAC is hijacking the system volume control, so it works just like normal but is actually being handled in the device...

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e-mail sent

Quote:

beaver316 said:

 
I'dbe very interested to know which USB cable you bought.

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just a random cable from the local market, costs me 20 hk dollars~
ask the staff in the shop, specifically mention USB "OTG" and that should work

Quote:

wir3d said:

mm that will be possible, but one of 2 things may be happening, 1 it may be using digital volume control on the device, which means you will lose bits and thus a loss of quality if it is not on 100%, or 2, which some DACs do, the DAC is hijacking the system volume control, so it works just like normal but is actually being handled in the device.
 
There is an issue with the RSA predator, the DAC is USB powered, just like the ODAC, so you are at the mercy of the S3's 100mW limit, it would help all of us if you contacted RSA and asked how much power the DAC section needs to run properly, and then USB power as we have figured is notoriously dirty, which will hammer the SQ again. 
 
For portable USB audio devices for android and such, it seems its imperative that the DAC/AMP powers itself for best SQ.

Click to expand...

 
Wait a second, I thought the Predator could run off it's own internal battery?
 
Edit: Oh bugger, I see. Be very interested to know the result of that email then, since I was looking at getting the Predator.

Hi Peter! Could you post a picture of your S3/Predator combo?
 

my gears, not so portable yet as the cables are quite messy
 

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Quote:

peterpenhk said:

my gears, not so portable yet as the cables are quite messy

 

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I really like this pic. Does the phone use the DAC as well as the amp with this setup? Also where can i find those usb cables. Im looking to get similar cables for my Desire HD which might be getting a Jelly Bean port in the future so i may be able to use my E17 with it. 

Thanks, Peter! Looks great.
Is your library FLAC-based? Which app are you using there?
As for the cable, you can get one of these suggested earlier in this thread.
 
Quote:

peterpenhk said:

my gears, not so portable yet as the cables are quite messy

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Ray has replied me:
 
"The DAC is powered by the USB 5 volts battery. So I won't recommend it with the phone as it will drain the power fast out of your battery."
 
Actually I don't fully understand his reply, is there a standard for the current of the usb port so we can find the Power?? Anyways I think both the amp and DAC sections in the Predator has been used. And since Ray mentioned about the battery life, I am going test it out tomorrow, just wait for my good news 
 
My library contains mainly Apple formats( Aiff and applelossless), but minority in FLAC as I've downloaded some hi-res files from HDtracks, Linn and B&W. Going to rip all my coming CDs in FLAC though, to feed my SIII

Quote:

peterpenhk said:

Ray has replied me:
 
"The DAC is powered by the USB 5 volts battery. So I won't recommend it with the phone as it will drain the power fast out of your battery."
 
Actually I don't fully understand his reply, is there a standard for the current of the usb port so we can find the Power?? Anyways I think both the amp and DAC sections in the Predator has been used. And since Ray mentioned about the battery life, I am going test it out tomorrow, just wait for my good news 
 
My library contains mainly Apple formats( Aiff and applelossless), but minority in FLAC as I've downloaded some hi-res files from HDtracks, Linn and B&W. Going to rip all my coming CDs in FLAC though, to feed my SIII

Click to expand...

yes USB is 5V, but we want to know the wattage, there is a standard, that I don't have the time to google, but phones fall under low power USB devices which are capped at 100mW AFAIK. 
And I know the ODAC needs 125mW, I am curious what the SGS3 needs, if it uses the Tenor chipset it could be about the same (guessing.)
 
Oh use neutron player, only app I have ever bought, horrible interface, but sound quality is second to none, the only player that comes remotely close is Player Pro, and its still a way behind the new 64bit NEON enhanced Neutron MP (buy the normal neutron first, then install the 64bit Neon (if your phone supports NEON) enhanced from their website over the play store version.) 
And trust me I have tried MANY different players.
 
Yeah lol, its far from portable. Here's me waiting for the Fiio Devices. Would actually be curious if they made a top tier device like the VAMP. But I don't think they are interested in competing at that level, but it would give their customers something to aspire to. 
 
I'm also still hoping for a USB/SPDIF dac or decoder that supports DTS and Dolby, and can apply dolby headphone. Yeah right.... big dreams

Clean 5V power for sound improvement of USB DAC:
http://www.aqvox.de/usb-power_en.html
 
"Elijah Audio from South Australia "introduces a new range of unique USB audio products designed to replace 5V PC/Mac power with clean 5V battery power." 
http://6moons.com/news/news.html
http://app.audiogon.com/listings/eljah-audio-isolaate-bl-750-battery-power-for-everyone
 

 
 
"I just added an external linear power supply to the ODAC and the performance improvement is immediate. No longer sounds strained and now the soundstage is nice and wide (I am using speakers not headphones). Overall 'clinical' quality is still there but certainly could be due to other factors. So power is definitely a factor in my case."
"I used this usb extension."
http://www.audiocircle.com/index.php?topic=105728.msg1105163#msg1105163
http://www.audiocircle.com/index.php?topic=105728.msg1105224#msg1105224
 

 
 
Another possibility: a small battery powered USB hub linking the USB powered DAC to the Android phone.