Android phones and USB DACs | Page 139 | Headphone Reviews and Discussion - Head-Fi.org

DanBa · Apr 7, 2013 at 10:03 AM

A USB OTG device, like the Galaxy S3, is a dual-role USB device, sometimes a USB host, sometimes a USB peripheral:

A USB OTG software program and USB OTG hardware components are added at the USB level.
A USB OTG device is configured to USB host mode or USB peripheral mode by USB OTG software/hardware measuring the value of the ID or Sense resistance (i.e. pin 4) of the USB interface.

When the Micro-B plug of a regular cable is inserted into the Micro-AB receptacle of a USB OTG-capable Android device, the Sense resistance is greater than 10Ω, and the Android device is configured to USB peripheral mode.

When the Micro-A plug of a so called OTG cable is inserted into the Micro-AB receptacle of a USB OTG-capable Android device, the Sense resistance is less than 10Ω, and the Android device is configured to USB host mode.

USB is a master-slave communication bus: USB communication can only take place between a master device or USB host, and a slave device or USB peripheral.

As standard USB DAC is always operating as USB peripheral, the USB OTG-capable Android device should operate as USB host.

James1776 · Apr 7, 2013 at 12:12 PM

I am looking for a short USB 'A' to a mini 'A'....cannot seem to find it. This is the exact cable used with the Fiio E07K, but much shorter...

Huxley · Apr 7, 2013 at 12:32 PM

Quote:

james1776 said:
I am looking for a short USB 'A' to a mini 'A'....cannot seem to find it. This is the exact cable used with the Fiio E07K, but much shorter...

This?

http://www.ebay.co.uk/itm/Short-USB2-0-Extension-Cable-A-Female-to-Mini-5-pin-Male-20cm-USB-Adapter-Cable-/271038194387?pt=UK_Computing_USB_Cables&hash=item3f1b22a2d3

James1776 · Apr 7, 2013 at 12:42 PM

What is the difference between a mini 'A' and a mini 'B' and a mini 5 pin???

Fiio calls the cable a 'A' male to a mini 'A' but darned if I can find anything but pictures of a mini 'A'

????

Huxley · Apr 7, 2013 at 1:42 PM

The fiio uses a regular usb mini, i know as I have the E7 myself.

So I take all you require is a regular usb on the other end. If so the above link is fine.

Unless you require a male usb like this

http://item.mobileweb.ebay.co.uk/viewitem?itemId=160853541890&index=0&nav=SEARCH&nid=07354827374

lostinthesauce · Apr 7, 2013 at 1:51 PM

Quote:

james1776 said:
What is the difference between a mini 'A' and a mini 'B' and a mini 5 pin???

Fiio calls the cable a 'A' male to a mini 'A' but darned if I can find anything but pictures of a mini 'A'

????

Mini-B on left Mini-A on right. Note the more squared off Mini-A connector. (Shamelessly borrowed from www.penguin.cz).

James1776 · Apr 7, 2013 at 2:37 PM

Looks like the one on the left...

lostinthesauce · Apr 7, 2013 at 5:10 PM

Quote:

james1776 said:
Looks like the one on the left...

I can confirm that the E07K uses a mini-b plug as it is what the Lindy cable I bought is terminated in.

BriX · Apr 7, 2013 at 6:31 PM

Quote:

danba said:
Audio Stream Format Type Descriptor of HRT microStreamer:
Format Type:   1 PCM
Number Of Channels:   2 STEREO
Sub Frame Size:   2
Bit Resolution:   16
Sample Frequency Type:   0x05 (Discrete)
Sample Frequency:   96000 Hz
Sample Frequency:   88200 Hz
Sample Frequency:   48000 Hz
Sample Frequency:   44100 Hz
Sample Frequency:   32000 Hz

Usually the first sampling frequency is the lower frequency.

I'm not very knowledgable in this area but are you saying that the Sample Frequency order may be what's causing the playback issues between the S3 and the HRT Microstreamer? Could you elaborate on this a little more in layman's terms?

**UPDATE** - Spoke with Kevin Halversen, CTO at HighResolutionTech. He looked the USB-AR-PRO debug log over. Saw a number of errors. He suggested I try running the OTG from the S3 into a self-powered USB hub and then into the MicroStreamer. I'm not sure what this will accomplish, but it does create a challenge in powering my "portable" rig without a wall-wart.

Any thoughts on how I can move forward here?

Thanks,

- B

DanBa · Apr 8, 2013 at 3:10 AM

This is only to point out an anomaly I found.
May be, it could help the USB Audio Recorder PRO developers.

In order to be able to interact with a USB DAC, a PC / Mac / Android device has to know what the USB DAC is able to perform by issuing questions to the USB DAC: it’s a USB enumeration step.

If a response is abnormal, it could mislead the interpretation.

Coop · Apr 8, 2013 at 3:34 AM

Quote:

brix said:
**UPDATE** - Spoke with Kevin Halversen, CTO at HighResolutionTech. He looked the USB-AR-PRO debug log over. Saw a number of errors. He suggested I try running the OTG from the S3 into a self-powered USB hub and then into the MicroStreamer. I'm not sure what this will accomplish, but it does create a challenge in powering my "portable" rig without a wall-wart.

Any thoughts on how I can move forward here?

What it will accomplish? Well, USB devices can require more power than OTG can deliver. Using a hub like this, will power the MicroStreamer according to regular USB spec.
You can use one of those portable USB chargers to power the hub.

IMHO this would be a good way to check if power is the problem. But it wouldn't be very practical in daily use. the addition of a USB hub and External battery wont do poratbility much good.

At the moment I'm looking into building a OTG cable that mimics an audiodock. That way I can use external power to power my DAC and charge my phone, while still having USB OTG functionalty at the same time. I want it so I can charge my phone while using it as an audio source while using it in my car. but it could be used in your situation too, and eliminate the need for an USB hub (you'd still need the external power source though).
To get this functionality you'd have to put a 64.9 kilo ohm resistor in the jump between sensor & ground pins on your OTG cable. I haven't tried it yet, as I don't have the appropriate resistor yet.

lostinthesauce · Apr 8, 2013 at 3:52 AM

Adding to the mystery here's a screenshot that proves my Note 2 recognises the E07K...and I was mistaken; the message that pops up states "USB connector connected". Further causing me to question my sanity is that when first starting up the USB Recorder it asks for permission to access the usb device. I really don't understand WHY the Note 2 will not pipe the audio through the E07K using anything but the USB Recorder. And that's to include the stock player (audio or video), Nuetron MP, BSPlayer, VLC, etc.

DanBa · Apr 8, 2013 at 4:28 AM

Quote:

brix said:
**UPDATE** - Spoke with Kevin Halversen, CTO at HighResolutionTech. He looked the USB-AR-PRO debug log over. Saw a number of errors. He suggested I try running the OTG from the S3 into a self-powered USB hub and then into the MicroStreamer. I'm not sure what this will accomplish, but it does create a challenge in powering my "portable" rig without a wall-wart.

Any thoughts on how I can move forward here?

How about using a slim USB battery connected to the S3 thru a Y-cable or a small powered USB hub?

DanBa · Apr 8, 2013 at 4:33 AM

Davy Wentzler · Apr 8, 2013 at 7:43 AM

Hi,

Version 1.1.0 of USB Audio Recorder PRO has been released yesterday. It uses a lot less cpu time for playback (can be more than 50 times less) and solves issues where higher buffer sizes lead to skipping playback. Besides that, it supports multichannel recording, but I guess that's not interesting for you HiFi people!

Enjoy,

Davy

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