iPad and external DACs

Posted by soundchekk (A) on August 17, 2012 at 01:57:52

Hi there.

The iPad allows to connect external USB DACs via CCK... ...under certain conditions.

iPeng - the iPad player app - meanwhile supports up 2 24/96 playback (even as PCM stream) (- iPhone is limited to 48khz.)

To me all this looks quite attractive on the first glance.

As usual, there's always a "but".

Problem:

USB power.

Obviously the iPad won't power USB DACs with rather high (>100mA???)power consumption.

The problem is that even self powered devices ( not all -- but many ) - if directly connected - won't work.

iOS will complain about too much power consumption.

I did a test by using a USB cable with cut off 5V. No change.
I did another test by powering up the iPAD with DAC connected ( somebody suggested this). No change.

The only way to make it work was by hooking up a selfpowered USB-Hub in between iPAD and DAC.

Scratching my head, hmmh... ...I guessed - it must be a software/firmware issue.

Finally I stepped over a comment that stated that USB devices
need to announce estimated power consumption to the host.

Question:

Could it be that all those selfpowered USB-DACs that just work with
a hub in the line, don't announce the power consumption to the host??

That's just a thought. Would be nice if affected manfuctarers would look into the subject. Similar things might happen on Android devices soon.

Cheers

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Topic - iPad and external DACs - soundchekk 01:57:52 08/17/12 (29)

RE: iPad and external DACs - soundchekk 08:01:11 08/18/12 (1)

RE: iPad and external DACs - soundchekk 03:22:57 08/27/12 (0)

it was deliberate - Joe Murphy Jr 11:06:50 08/17/12 (11)

RE: it was deliberate - of course it was....Apple looks out for Apple first and foremost - Dynobot 12:36:06 08/17/12 (10)

Thanks for the revelation - bwb 15:22:25 08/17/12 (9)

Wrong - Dynobot 15:32:35 08/17/12 (8)

Really? - bwb 17:25:07 08/17/12 (7)

It is what it is - Dynobot 17:59:52 08/17/12 (6)

twist my words, add words into my mouth...... - fmak 11:30:44 08/18/12 (5)

RE: twist my words, add words into my mouth...... - bwb 11:56:46 08/18/12 (4)

LOL !! - AbeCollins 18:48:07 08/18/12 (3)

RE: LOL !!Yes - fmak 03:37:30 08/19/12 (2)

come on - bwb 04:58:31 08/19/12 (1)

B. H. was one of the greatest...nt - Dynobot 05:00:29 08/19/12 (0)

I imagine it's not too convenient to use iPad as a hammer, either. - carcass93 09:06:16 08/17/12 (1)

RE: I imagine it's not too convenient to use iPad as a hammer, either. - Daverz 19:15:27 08/17/12 (0)

RE: iPad and external DACs - Gordon Rankin 08:46:59 08/17/12 (3)

RE: iPad and external DACs - soundchekk 00:12:06 08/18/12 (2)

RE: iPad and external DACs - rick_m 06:44:26 08/18/12 (1)

RE: iPad and external DACs - soundchekk 06:58:09 08/18/12 (0)

RE: iPad and external DACs - AbeCollins 07:55:08 08/17/12 (8)

RE: iPad and external DACs - Dynobot 09:38:38 08/18/12 (1)

Dac Hanging Off iPod Touch - Dynobot 13:03:39 08/20/12 (0)

RE: iPad and external DACs - Old Listener 09:30:38 08/18/12 (1)

RE: iPad and external DACs - AbeCollins 10:42:28 08/20/12 (0)

cars and home setups - Joe Murphy Jr 10:40:44 08/17/12 (2)

RE: cars and home setups - mhardyman 10:47:40 08/17/12 (1)

if not, see my response to soundchekk [nt] - Joe Murphy Jr 11:08:52 08/17/12 (0)

RE: iPad and external DACs - Dawnrazor 09:14:26 08/17/12 (0)

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