[AudioI] Microphone preamplifier

Ivan probecomp2 at googlemail.com
Thu Feb 10 20:46:44 UTC 2022 

To follow up on David's comment, in regards to installing it into a chassis
and building an actual product around it... What would also make this
easier and much more convenient, is if all the XLR connectors were on the
same side.

Specifically, on the same side where the input XLRs are now, and that the
connectors also line-up flush with the network and USB connectors on the
Pi.

One could then build an enclosure, the back of which would have audio
connectors and most important Pi connectors (except power) for a headless
product.


Regards,
Ivan

On Thu, Feb 10, 2022 at 4:46 PM David Vanmanshoven <
david.vanmanshoven at fordata.be> wrote:

> Hi Matt,
>
> A microphone pre-amp would indeed be very interesting for one of my
> projects:
> - phantom power 48V integrated, but controllable via GPIO
> - a gain potentiometer is also necessary, also preferably controllable via
> GPIO
> - It would be nice to have the print directly soldered on an XLR-port so
> that it is easy to install into a chassis like this:
> https://www.electronics-lab.com/project/tiny-proffesional-microphone-preamplifier/
>
> Kind regards,
>
> David
>
>
> -----Original Message-----
> From: People <people-bounces at lists.audioinjector.net> On Behalf Of
> people-request at lists.audioinjector.net
> Sent: donderdag 10 februari 2022 13:00
> To: people at lists.audioinjector.net
> Subject: People Digest, Vol 25, Issue 5
>
> Send People mailing list submissions to
>         people at lists.audioinjector.net
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://lists.audioinjector.net/mailman/listinfo/people
> or, via email, send a message with subject or body 'help' to
>         people-request at lists.audioinjector.net
>
> You can reach the person managing the list at
>         people-owner at lists.audioinjector.net
>
> When replying, please edit your Subject line so it is more specific than
> "Re: Contents of People digest..."
>
>
> Today's Topics:
>
>    1. Re: Microphone preamplifier (Matt Flax)
>    2. Re: Microphone preamplifier (Ivan)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 9 Feb 2022 22:10:21 +0000
> From: Matt Flax <matt at audioinjector.net>
> To: Ivan <probecomp2 at googlemail.com>, people at lists.audioinjector.net
>         <people at lists.audioinjector.net>
> Subject: Re: [AudioI] Microphone preamplifier
> Message-ID:
>         <
> 0100017ee0899c3f-e3054610-af75-4f45-bb82-f22f6558c27c-000000 at email.amazonses.com
> >
>
> Content-Type: text/plain; charset="utf-8"
>
> 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 <mailto:
> 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
>  >
>  --
>  Checkout the community email list :
>  https://lists.audioinjector.net/mailman/listinfo/people
>
>
>
>
>
>
>
>
>
>
>
> --
> Checkout the community email list :
> https://lists.audioinjector.net/mailman/listinfo/people
>
>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://lists.audioinjector.net/pipermail/people/attachments/20220209/04b3f5dc/attachment-0001.htm
> >
>
> ------------------------------
>
> Message: 2
> Date: Thu, 10 Feb 2022 12:27:49 +0100
> From: Ivan <probecomp2 at googlemail.com>
> To: Matt Flax <matt at audioinjector.net>
> Cc: "people at lists.audioinjector.net" <people at lists.audioinjector.net>
> Subject: Re: [AudioI] Microphone preamplifier
> Message-ID:
>         <CAAOPoqRi1JhQno1tVYm=B8-W2Ow_tppbmS27=
> OpG9cEoTBwtbA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> 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
> >> >
> >> --
> >> Checkout the community email list :
> >> https://lists.audioinjector.net/mailman/listinfo/people
> >>
> >>
> > --
> > Checkout the community email list
> > :https://lists.audioinjector.net/mailman/listinfo/people
> >
> >
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://lists.audioinjector.net/pipermail/people/attachments/20220210/84a10f68/attachment-0001.htm
> >
>
> ------------------------------
>
> Subject: Digest Footer
>
>
> --
> People mailing list
> People at lists.audioinjector.net
> https://lists.audioinjector.net/mailman/listinfo/people
>
>
> ------------------------------
>
> End of People Digest, Vol 25, Issue 5
> *************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.audioinjector.net/pipermail/people/attachments/20220210/bf13fc2e/attachment-0001.htm>

More information about the People mailing list