Pure i-20 iPod/iPhone Dock as a DAC - Page 24

My switching power supply is making a high pitched buzz. Anyone have any thoughts/suggestions? Perhaps I should replace it. 

^ You can reset or double reset your iDevice and see if it works. This may have been mentioned here in this thread but I have not done it myself:

http://www.head-fi.org/t/529956/pure-i-20-ipod-iphone-dock-as-a-dac/105

Edit: try this:

Hold the Power and Home buttons until the screen goes dark and the Apple icon comes on. Then let go and do this process immediately again. The second time the Apple icon comes on, let go and allow the iPhone to finish rebooting.

The noise is actually coming from the power source. If I unplug the i20 the power source continues to make the noise. If I unplug the power pack it stops. Very strange. 

I just got one and really like this thing.  As a value proposition its hard to beat-although i have not tried the analog outputs yet, just with an ipad as a transport to my mhdt and meitner dacs. 

I like to turn the lights low and have the light of the ipad glowing. What think would kinda cool is to find some kind of blue light, lava light program that adjusts to the music while its playing....sort of like the background behind a band at a concert. In other words a transport, dac, and a mood lamp

Quote:

Originally Posted by davebtw 

I just received my Pure i20 yesterday.  I am using it as a doc for a iPhone4, feeding the SPDIF output to an original Benchmark DAC-1.  So far so good.  It definitely sounds a lot better than the iPhone4 own headphone output on my HD-600s.

 

Having not previously read these forums I was surprised that there is a volume control in the signal path, only adjustable from the i20 remote.  I was hoping for bit-accurate digital output with no processing.  However, it still sounds very good.  I will be running some tests very soon on the output bit depth and resolution which I will post on my blog.  Please stay tuned!

 

-david BTW

Just another alternative to Pure-i-20 to connect idevice to a AMP. ....Fostex HP-P1 .

it is smaller in footprint ( portable ) , take data directly from Idevice as well , have a very inbuilt DAC ( better than I-20) and connect them directly to a Amp.

if you choose to use it for portable use. it is a DAC/AMP . only issue that i had with it is that AMP portion is not as good as standalone Amp. but it is more than enough for lower Ohm Headphones.

Another good choice will be ALO Alogr. Solo DAC. 

but they are many times more pricing compare with I-20 .

Thanks 

Raymond Lim 

I'm very curious to know whether davebtw (or anyone else) has ever measured and verified whether the Pure i-20 outputs bit-perfect data from the iPod/iPhone/iPad when used as a digital transport to an external DAC.  I've searched this forum in vain for any conclusive evidence that the output is bit-transparent (by contrast, it has been well-documented elsewhere that output from the iPad via the Camera Connection Kit to certain USB DACs is bit-perfect all the way up to 24/96 files, e.g.,  http://www.benchmarkmedia.com/discuss/feedback/newsletter/2011/06/1/ipad-streams-high-resolution-audio-dac1).

I am equally interested to know whether anyone has verified that the i-20 will output full 24/96 resolution music files when used as a digital transport to an external DAC, either with an iPhone or iPad using FLAC Player or some other player that can store and access 24/96 files.  I realize the iPhone is limited by Apple to 24/48 output (though this is no longer true of the iPad), but if I can store 24/96 FLAC files locally on the iPhone with FLAC Player, and the i-20 is acting as a pure digital transport, shouldn't the full resolution of those files be visible to the i-20 and output to the external DAC?  In other words, wouldn't bypassing the iPhone's integrated DAC completely remove any hardware limitations on playing high resolution 24/96 files?

Thanks very much.  I have an i-20 hooked up to a Benchmark DAC1-USB via optical with both an iPhone 4S and iPad 2, and it would be great to verify that 100% of the data from high resolution files is being sent unaltered to the DAC1 from one or both devices.
 

Quote:

Originally Posted by davebtw 

I sent in a tech support request to Pure and after some back and forth trying to find the right words so the tech support engineer got the real question I today received this really pretty clear answer:

 

Dear David,

The maximum volume control setting on i20 sets 0dBfs digital output level within the DSP which converts asynchronous USB packetized audio data from the iPod to I2S audio data (i20 system) to feed the D/A converter within i20 and also to feed the digital outputs (S/P-Dif).

This can be quickly verified with a digitally generated file of -nndBfs added to the iPod playlist and then played out of the S/P-DIF path on i20 and digitally captured, as digital interfaces pass level in absolute dBfs with 0dBfs being the highest magnitude signal that can be described.

N.B. Additionally, yes, using the digital volume control at a setting other than 0dBfs (maximum) does manipulate the audio stream to reduce volume and hence with large shifts (SNR)

Regards,
 
David Wilson

 

 

I will be confirming this with real measurements when I get my lab (and Audio Precision System Two Cascade) rebuilt in the very near future.  In the meantime, it appears that once the iPhone4 is on the doc, running up the volume to full using the i20 remote will provide the best digital output, with the most dynamic range and maybe even bit-accurate when using apple lossless format(we shall see).  There is no indication that the volume control is going up or down on the screen, so one just has to keep hitting the up command until convinced it is up all the way.

 

Have Fun,

 

-david BTW

 

Can the Pure i-20 dock an iPhone without removing the phone case?  

My snug fitting bamboo wood case from Grove is not easily slipped off & on.  Thanks.

I have the Incipio NGP Case on my iPhone which is fairly thin and accessible at the bottom (by eyeball I'd guess it adds roughly 1-2mm of separation from the surface of the i-20), and I could not make a connection at all through it.  It's maddening, actually, that Pure (and so many other dock manufacturers) don't give some added length to their 30-pin iPhone connectors to accommodate even basic (non-bulky) cases.  It's hard to believe there are very many people out there that use their iPhones without cases.

I solved the problem by purchasing the SendStation Dock Extender for iPod to put between my iPhone and the i-20.  It functions perfectly, and, even though the iPhone sits 1/2-inch higher now, the back of the i-20 is just high enough that it remains quite stable.  It does look a little silly to me to have the iPhone seated even higher than the already high placement in the dock, but as long as it's stable I can live with it.  If you don't mind having the iPhone rest off to the side of the dock, you could alternatively purchase a 30-pin extension cable.  Or, of course, remove your case every time you want to dock it.
 

Quote:

Originally Posted by always learning 

Can the Pure i-20 dock an iPhone without removing the phone case?  

 

My snug fitting bamboo wood case from Grove is not easily slipped off & on.  Thanks.

Two Questions:

1) Anyone tried some kind of upgraded power supply? I see there is one avaialble in the uk but have not seen anything in the states or if it would be worth the effort

2) Anyone compared  any hi rez files played through the pure's own dac versus standard files to their own existing dac?  Obviously this would be source and dac dependant but trying to get a general read if the pure playing some 24/94 tracks from HD Tracks.com would be worth the hassle since both my dacs only do 44

I asked Pure's technical support (who responded very quickly with some excellent technical information, which I've pasted below) whether, if I store and play 24/96 FLAC files on an iPhone 4S with the FLAC Player app, the full 24/96 resolution of the files will be passed through the Pure i-20 to an external DAC via SPDIF.  He answered in the affirmative at the very end, but the detailed information he gives in the main body of his response seems to contradict in some ways the short summary answers he gave to questions #1 and #2 at the end.  Can anyone else shed light on this?  Has anyone verified that the Pure i-20 will pass through full 24-bit / 96 KHz audio data to external DACs from either the iPhone or iPad?  Thanks!

Quote:

Originally Posted by schaqfu 

I'm very curious to know whether davebtw (or anyone else) has ever measured and verified whether the Pure i-20 outputs bit-perfect data from the iPod/iPhone/iPad when used as a digital transport to an external DAC.  I've searched this forum in vain for any conclusive evidence that the output is bit-transparent (by contrast, it has been well-documented elsewhere that output from the iPad via the Camera Connection Kit to certain USB DACs is bit-perfect all the way up to 24/96 files, e.g.,  http://www.benchmarkmedia.com/discuss/feedback/newsletter/2011/06/1/ipad-streams-high-resolution-audio-dac1).

 

I am equally interested to know whether anyone has verified that the i-20 will output full 24/96 resolution music files when used as a digital transport to an external DAC, either with an iPhone or iPad using FLAC Player or some other player that can store and access 24/96 files.  I realize the iPhone is limited by Apple to 24/48 output (though this is no longer true of the iPad), but if I can store 24/96 FLAC files locally on the iPhone with FLAC Player, and the i-20 is acting as a pure digital transport, shouldn't the full resolution of those files be visible to the i-20 and output to the external DAC?  In other words, wouldn't bypassing the iPhone's integrated DAC completely remove any hardware limitations on playing high resolution 24/96 files?

 

Thanks very much.  I have an i-20 hooked up to a Benchmark DAC1-USB via optical with both an iPhone 4S and iPad 2, and it would be great to verify that 100% of the data from high resolution files is being sent unaltered to the DAC1 from one or both devices.
 

 

 

Hello, to i-20 owners :

Could you confirm me that every apps are compatible with i-20, what I mean is the sound of apps like u-pnp reader, internet radio, spotify ,  will be successfully translated on the numeric port of the i-20 ? I need this confirmation because my Marantz CD 6003 is only able to play the files stores on my Ipod touch.

Thanks !

Florent

Welcome to Headfi!

MOG works from coaxial, rca and optical output.

Youtube works from video output.

I am using 3GS on iOS 4.1 and 5.0

Sorry, do not have the apps you mentioned. 

So should be OK with every app ! I think I am going to buy one and try it !

Thanks a lot for your answer zzffnn

Florent.

Surprised and confused....

I have the following gear setup in my office rig - run-in time about two weeks now:

160GB iPod Classic w/lossless files -> Pure i-20 -> Centrance DACmini -> Lehmann BCL -> Sennheiser HD650 or ATH-W1000

Now, to make things more interesting, I've connected the Pure i-20 dock with the DACmini using all 3 appropriate cables - digital coax, fiber optic, and analog (RCA).  Then I've taken the RCA out from the DACmini to the RCA analog in on the BCL, just for grins.

Now for some listening.........hmmmmmm.  Using the headphone out from the DACmini, I'm truly perplexed.  I can switch back and forth between sources, yet the difference seem incredibly minor.  In fact, with an assitant helping me - I consistently fail nearly every blind test I tried.  Even when I can hear (very minor) difference between the various inputs - I can't in any meaningful way commit to the idea that one is "better" (to my ear) than another.  In the few cases where I DO think I like one input more than the others, it was consistently the analog input from the Pure dock.

HUH!?!!!????

So, totally confused by that result, I completely disconnected everything and just took the analog output from the Pure dock and pumped it directly into the Lehmann BCL amp - taking the DACmini out of the picture (both amp and DAC). 

Low and behold, it sounds better than any of the other combinations.

I'm open to your input, thoughts and recommendations.....how can this possibly BE?

Believe your ears.  The DAC in the Pure must be better than the DAC in the DACMini