[AudioI] zero soundcard with phantom power

[Matt]

On 21/9/20 3:36 am, Serge Ortega via People wrote:
> Good morning all
>
> Many thanks to all for your very informative answers.
> My goal is to develop a small wifi intercom system with headsets based 
> on raspberry Zero. I am thinking of powering them with LiPo batteries 
> or 9V batteries ... I am in the process of designing.
> There are different models of headsets, some dynamic and others 
> static, hence the need to use a phantom power supply of at least 12V.
> If you have any suggestions to help me develop this project, thank you 
> very much.
> In terms of development, I am thinking of using gstreamer: what do you 
> say?


I haven't used gstreamer. Some people like to use the rtsp protocol 
because it is low latency. I think gstreamer will implement that. There 
is also VLC and ffmpeg (avconv).

You may be interested in this old project which implemented half duplex 
communications : https://github.com/flatmax/halfDuplex

It is implemented in bash and uses ssh, ffmpeg and screen. It may need 
some updating to work - for example it still uses ifconfig rather then 
the ip command.


>
> Matt, I congratulate you on the development of your products. Your 
> offer is already very complete and geared towards "professional" 
> equipment. Thank you so much !


Thank you !


>
> Serge
>
> Le 20/09/2020 à 09:20, Matt via People a écrit :
>>
>> This is all good information. I got a bit more to add.
>>
>> The zero will give you power for an electret capsule microphone - 
>> typically < 3V power.
>>
>> The analogue breakout standard (AI-ABS) implements the 48V phantom 
>> power for you : 
>> https://github.com/Audio-Injector/AudioInjector-Analogue-Breakout-Standard
>>
>> https://github.com/Audio-Injector/AudioInjector-Analogue-Breakout-Standard/blob/master/AudioInjectorAnaBreakStdv1.pdf
>>
>> The power header gives > 48V power. You will want to regulate this 
>> with a 48 V linear regulator before using it.
>>
>> Our first soundcard to implement the AI-ABS is the Isolated soundcard 
>> (already available for purchase). You can design a preamplifier for 
>> this board which uses the phantom power. Alternatively you can wait 
>> for a later preamplifier release which will implement an optional 
>> phantom powered microphone preamplifier.
>>
>> Let us know which direction you plan to go, plenty of Audio Injectors 
>> here with great suggestions and willing to help.
>> Matt
>>
>> On 20/9/20 3:00 am, Francois Dion via People wrote:
>>> Behringer PS400 is about $30 street price and does the job. Provides 
>>> about 30mA on 48V. Can also power phantom 12V.
>>>
>>>
>>> Francois Dion, Chief Data Scientist
>>> Dion Research LLC | Analytics, Data Science & Visualization
>>> dionresearch.com <http://dionresearch.com> | @DionResearchLLC | PO 
>>> BOX 12786 | WINSTON-SALEM NC 27117
>>>
>>>
>>>
>>> On Sat, Sep 19, 2020 at 12:02 PM Randy Reichenbach via People 
>>> <people at lists.audioinjector.net 
>>> <mailto:people at lists.audioinjector.net>> wrote:
>>>
>>>     That would be nice, right?  You could certainly add phantom
>>>     power to a Zero card, but understand that Pro mics like the NT5
>>>     require 48VDC phantom power, and the Pi and AI Zero just have 5v
>>>     and 3.3v onboard.
>>>
>>>     So, you could add a separate phantom power supply. Plenty of
>>>     examples of that if you google.
>>>
>>>     Or you could use a buck/boost converter to take the 5V and boost
>>>     it to 48.  Mics only require single digits of mA, so the power
>>>     requirement is actually rather low.
>>>
>>>     Here's an example of a 9v to 48v.
>>>     https://www.electronics-lab.com/project/9v-to-48v-dc-dc-converter/
>>>
>>>     The spec for that regulator:
>>>     https://www.sparkfun.com/datasheets/IC/MC34063A.pdf
>>>
>>>     suggests it'll work down to 3v, so there you go.
>>>
>>>     OR it's likely that AudioInjectors Preamp board would have you
>>>     covered, though strangely, it doesn't mention phantom power.  As
>>>     much as I love my AI cards, I find the available info about them
>>>     to be rather lacking.
>>>     http://www.audioinjector.net/xlr-preamp
>>>
>>>
>>>
>>>     On Sat, Sep 19, 2020 at 1:55 AM Serge Ortega via People
>>>     <people at lists.audioinjector.net
>>>     <mailto:people at lists.audioinjector.net>> wrote:
>>>
>>>         Hi everybody
>>>
>>>         I would like to know if it is possible to use a standard
>>>         electret
>>>         microphone (like Rode NT5 for instance) with a zero soundcard ?
>>>         Is the power like a phantom ?
>>>
>>>         Thanks for your answer
>>>         Sergio
>>>
>>>
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>>>         People mailing list
>>>         People at lists.audioinjector.net
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>>>
>>>
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