Battery Powered USB Hub

Started by Elantric, May 09, 2013, 05:25:01 PM

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Elantric

Battery Powered USB Hub
Why is this unit required?  Because using the Apple CCK with the latest IOS devices, Apple has placed a max limit on the total electrical current that can be delivered from an Iphone or Ipad to an external USB device. Regardless if your external USB Class Compliant device uses its own power, the truth is in practice many USB Class Compliant devices will require the addition of a Powered USB Hub to be inserted between the Apple CCK and the Audio Interface.

If you are near a Power Outlet, then most USB Hubs that include an AC Power adapter will work fine.

But what if its essential that your Guitar rig operate on total battery power?
Then read here on how to achieve that :

Use Focusrite Scarlett 2i4 + Fishman Tripleplay with iPad on Battery Power
https://www.vguitarforums.com/smf/index.php?topic=10323.0
   

Meanwhile if your AC Powered USB Class Compliant Audio / MIDI  interface "dujour" still will  not  power up when directly connected to your iPad+CCK without an IOS "Attached USB Device draws too much power"  Error message - then this might be the answer:   
CyberPower CPH420MP Battery Powered USB HUB - this Battery Powered USB HUB.
I feed it from my USB connection from the Apple USB Camera Adapter connected to iPad.
http://www.cyberpower-eu.com/products/accessories/hub/cph420mp.htm



Sadly the CyberPower CPH420MP is no longer manufactured, and near impossible to locate "new original stock" - so ive been seeking an alternative as a backup for this crucially important item in my portable iPad Rig.
 

Starting with IOS 4.1, Apple placed a restriction on the amount of power an external USB device can draw from the  Iphone / Ipad's Dock port  / Lightning port to 200mA  MAX.


To overcome this external USB device power restriction, use a Powered USB Hub between the Apple USB Camera Adapter and the Target USB Class Compliant Audio Device.

Background: Here is a site which explains typical USB Client USB architecture, and how many USB Audio and MIDI devices USB - UART chips are powered.


http://www.chameleon-dev.com/pmwiki.php/Community/AvrHardware
and a typical schematic:


At the top of the schematic above, you see an Arrow with the signal USB_5VOUT, this is the power coming in from the USB port (H1), which in our case is the IPAD. Many USB Audio and MIDI device's internal USB - UART chips (like U6 above) must be powered by the external USB Host device, and some of these chips draw excess of 200mA "in-rush current" momentarily while bulk 4.7uF Capacitors become charged, so you must use a Powered USB Hub which often can provide +5V @ 500mA, far in excess of the limited USB 5V @ 200mA supply current available by iPhone / iPad USB Camera Connection Kit adapters.


For mobility, I prefer a "self -powered" four AAA Battery operated  - Powered USB Hub with my iPad and some USB Class Compliant devices which require it.

I use a hard to find CyberPower Mobile Battery Powered 4-Port USB Hub (CP-H420MP)

http://www.amazon.com/CyberPower-Mobile-Battery-Powered-CP-H420MP/dp/B0002UQALQ/ref=cm_cr_pr_product_top



Here are plans for similar tech
https://forum.ableton.com/viewtopic.php?f=40&t=162744


--

Its really hit or miss on knowing which USB Audio / MIDI devices require the Powered USB Hub, and which ones dont.
To work with Ipad, many AC Powered USB Audio / MIDI Devices still require an external third party Powered USB Hub to power their internal USB - UART chips's  "in-rush current" for their bulk 4.7uF Capacitors.

But not every USB Class Compliant Audio device needs the Powered USB Hub.
See this link below for a list of Ipad compatible Audio interfaces and look at the column "Works without Powered Hub?"
http://auriaapp.com/Support/auria-audio-interfaces

I can tell you the following all work directly with iPad+USB Camera Adapter without need for an external Powered USB Hub.

Fender G-DEC 3

Korg Pandora PX5D

Fender Mustang Amps and Mustang Floor

Also many folks read the above and assume I'm suing the battery powered USB hub to power all my USB Audio / MIDI Interfaces - I'm NOT!

A'm only using the Cyber Power Battery USB Hub to power the USB UART in those devices  - other power supplies are employed to power higher current devices.

More details here:

https://www.vguitarforums.com/smf/index.php?topic=10323.0




cell7

This looks excellent, but i cant find any info on the internal battery... any idea of it's power rating? Did you order it as a sample from China or via a retailer?

mbenigni

Grateful for your R&D on these little accessories.  I'm a real stickler about avoiding AC power wherever possible.  I wish more musical equipment shipped with built-in rechargeable batteries of their own - at least as an option - acknowledging the inevitable increase in prices.

Elantric

#3
How to use Focusrite Scarlett 2i4 + Fishman Tripleplay with iPad on Battery Power Only

https://www.vguitarforums.com/smf/index.php?topic=9581.0

Ringleader

#4
Last night I discovered something really interesting and also really confusing. It seems that some USB hubs can confuse the iPad into removing or at least increasing the max current requirement (note I said "seems" but I have no idea what is really happening here). For example, I had three low-draw USB devices plugged into my iPad air and running all at once via a genuine USB to Lightning adaptor with no external power required.

Apogee JAM
Korg Nanokontrol
Fishman Triple Play

What's weird about it is that I have had this happen before to a lesser degree, but it usually resulted in unexpected behavior of the connected device - as if it was running at a bare minimum power draw and would sometimes fail after a short period of time (Ex: the FTP receiver would appear to be working but then wouldn't connect to the transmitter). But last night I got a full 1/2 hour out of this rig with nothing breaking (I had to stop, assuming could have gone longer). I've tried to connect these same devices together before using a different USB hub but only got two devices plugged in before receiving the too much power message so this is so odd that it worked.

Anyways, if anyone is in the market for a USB hub for the iPad and is interested in trying this out, here is the hub I used. It is actually built into my foot controller, but I don't see how that would make any difference.
http://www.amazon.com/Sabrent-Port-Individual-Power-Switches/dp/B005SZ66XM/ref=sr_1_3?s=electronics&ie=UTF8&qid=1389624928&sr=1-3&keywords=sabrent+usb+hub

Note that I am not making any promises or guarantees here, just sharing my experiences. And don't expect this to work with a high draw USB powered device such as a Focusrite or anything. I'd say that if your iOS device will power USB device on its own when it is the only device connected, then you'd have a chance of it working with other similar USB devices. Even if it does end up requiring an external power supply to work, this has been a great hub for me and the indidual power switches are really handy.

Elantric

#5
QuoteLast night I discovered something really interesting and also really confusing. It seems that some USB hubs can confuse the iPad into removing or at least increasing the max current requirement (note I said "seems" but I have no idea what is really happening here). For example, I had three low-draw USB devices plugged into my iPad air and running all at once via a genuine USB to Lightning adaptor with no external power required.

I'm seeing similar results in my iPad testing -


Read the  "Survey of USB Hubs" Thread" here:
https://www.vguitarforums.com/smf/index.php?topic=10326.msg74451#msg74451

because there exists many variables. And we need to target which Platform the Hub was running on.

For example  - Most USB 2.0 Hubs that work perfectly on an iPad Air (+CCK), may not be ideal on todays Laptops where High Speed USB 3.0 devices exist . And if you have a Macbook Retina with only two USB 3.0 ports, You will want  to locate a hub that can support all types of USB . Add there are many sub categories in the USB spec (USB High Speed , USB Full Speed , etc  I understand the Fishman Tripleplay is USB 1.1, BTW.

I find using passive non powered Hubs on iPad is like flipping a coin, one day they work - next they they don't. I had a particular Hub that was my "go to" Hub for iPad Audio / MIDI testing in 2012
http://www.amazon.com/USB-Highspeed-Port-Adapter-Silver/dp/B002FFZGCU/ref=sr_1_24?s=electronics&ie=UTF8&qid=1389627962&sr=1-24&keywords=USB+Powered+hubs

that apparently flat refuses to work now with IOS7 - Anything I connect to it (even with a separate Power adapter to the HUB) gives me either the "Device exceed power " type warning , or more specifically - IOS7 will pop up a warning spelling out the name of the connected device. I must have seen "Scarlett 2i4 is Not compatible with IOS" warning 100 times before I stumbled upon my working solution.

https://www.vguitarforums.com/smf/index.php?topic=10323.msg74428#msg74428
But its possible IOS8 next year will break it.

The reason is our world of connecting several USB Class compliant devices simultaneously to an iPad is something Apple tacitly allows, but can not officially endorse in a world of litigation and successful lawsuits the next time an iPad Air explodes because someone used a non Apple approved Power supply or Home brew Powered USB Hub.  For this reason Apple has the mFI (originally "Made for iPOD" but now expanded for all Apple IOS devices) Hardware Approval program. This explains why that new Griffin Studio Connect HD will not be available until 3rd quarter 2014. because after a third party manufacturer like Griffin gets the StudioConnect HD fully debugged and ready to go - they must send a working example to Apple engineers who do a thorough review, and can force a PC Board respin if they see a path of vulnerability to damage the iPad, or radiate too much RF, not pass FCC Class B consumer standards ( very stringent BTW) or recent Low voltage Directive UL/CE Low voltage standards. The old days of "Hey, this thing runs on a battery so it will never electrocute me" gets removed when you consider that Pads have all Metal cases and some folks work at an old 1940's Metal office desk with poor 1940's wiring, and 2 prong outlets no common Earth Ground connection and lots of potential for reversed grounds in part the house that only get exposed  when running today's tech devices.   

http://apple-singapore.com/ipad-air-exploded-in-australia/

http://www.deathandtaxesmag.com/209483/an-ipad-air-exploded-in-australia/

Ringleader

Quote from: Elantric on January 13, 2014, 07:19:01 AM
perhaps we need a "Survey of USB Hubs Thread", because there exists many variables. And we need to target which Platform the Hub was running on.

Agree, but if it is under the tablets and smartphones section I would prefer it be iOS (class-compliant) compatible hubs only. At least until Android gets their act together with latency and such.

Elantric

#7
But new Laptops with USB 3.0 ports have a whole different set of issues with USB Hubs too - 
Survey of USB Hubs
https://www.vguitarforums.com/smf/index.php?topic=10326.msg74451#msg74451

datsunrobbie


phals2002

Hi Elantric,

I want to know more about this USB hub with battery. Right now Im using TP Connect. And Im planning to purchase USB hub and put it in my pedalboard, so from TP connect ---> usb hub ----> ipad (with CCK).

What kind of usb hub suits for my setup? can you please give me info about the type / model so I can purchase it.

Thanksss