[AudioI] Microphone preamplifier

[Ivan]

The microphone pre-amplifier would need to accept both dynamic and
condenser studio microphones.

Ideally, the phantom power (+48V) could be turned on or off via the
software driver. This would be ideal. If this is too complicated to
develop, than a physical jumper on the board would do a job, preferably
available independently for each (left/right) channel, so that the
different types of microphones can be used at the same time.

Gain should also be sufficient, to raise the low microphone level.

This is just a suggestion (considering you've already started the
development) but potentially, the XLR board could be modified so that it
can be used as both a line input, or a microphone input (with switchable
phantom power). This would make it simpler to manufacture (one board,
instead of two) and the product itself more versatile for various
applications.

Regards,
Ivan

On Wed, Feb 9, 2022 at 11:10 PM Matt Flax <matt at audioinjector.net> wrote:

> Good to hear. The microphone preamplifier has been started - however there
> are a couple of other preamplifiers in line as well.
>
> I am keen to get ideas on different use cases for this card. For example,
> I would imagine that people would want the phantom feature. But what about
> dynamic microphones ?
>
> Matt
> On 9/2/22 21:21, Ivan via People wrote:
>
> Hi Matt,
>
> I would be very interested in the mic preamp if you were to design one, as
> I don't have the expertise...
>
> Is such a product on your roadmap? If so, how long do you expect it would
> take you to be able to offer it?
>
> Regards,
> Ivan
>
> On Tue, Feb 8, 2022 at 9:46 PM Matt Flax <matt at audioinjector.net> wrote:
>
>> Hi there,
>>
>> The XLR preamplifier is setup to carry up to around 20.4 V (about 19.4
>> dBu). The output preamplifier has a gain of 13 dB. The input
>> preamplifier has a gain of -12.8 dB.
>>
>> A good microphone preamplifier would require both phantom power (the
>> power rail is available on the Pro and Isolated soundcards) and also a
>> significant input gain of around 30 dB.
>>
>> It would be great if enough people were interested in this to either
>> design their own together, or given more time I can design one up.
>>
>> Matt
>>
>> On 4/2/22 21:24, Ivan via People wrote:
>> > Hello,
>> >
>> > I have a need to connect professional (condenser) microphones to the
>> > Raspberry Pi and I was wondering if I can use the XLR preamplifier
>> > with the Pro sound card, to do that?
>> >
>> > I've noticed that the sound card has the phantom power available, but
>> > I'm not sure if the XLR preamplifier has access to that and whether
>> > the gain is sufficient?
>> >
>> >
>> > Thanks,
>> > Ivan
>> >
>> --
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>>
>>
> --
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>
>
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