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Re: [micbuilders] Re: A very minimalist mic preamp from a rookie (a new drawing)

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  • Dominique M
    Welcome Nisios, I think the 1uF simply was a mistake. Sometimes you find a (much smaller, and depending on the resistance) capacitor at this place fo filter
    Message 1 of 10 , Apr 5 6:02 AM
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      Welcome Nisios,

      I think the 1uF simply was a mistake.
      Sometimes you find a (much smaller, and depending on the resistance)
      capacitor at this place fo filter any unwanted high frequency (higher than
      audio) noise.

      Cheers,
      Dominique

      ----- Original Message -----
      From: "minimal_nisios" <nisios@...>
      To: <micbuilders@yahoogroups.com>
      Sent: Wednesday, April 04, 2007 8:04 PM
      Subject: [micbuilders] Re: A very minimalist mic preamp from a rookie (a new
      drawing)


      >I have just finished my first mic. Its a XY stereo mic with a basic
      > preamp inside the body for field recording, powered from a 9v battery.
      > I made the pre amp from a text book and it is very similar to yours,
      > the only difference being the abcense of the 1uF capacitor on the
      > voltage divider. Can you tell me why you used that? What are the
      > advantages?
      > By the way this is the first time i write on this group. Im starting
      > my electronics quest....so please have a bit of pacience with me:)
      >
      > Cheers to everyone.
      > Nisios
      >
      > --- In micbuilders@yahoogroups.com, "mauricoma" <maurizco@...> wrote:
      >>
      >> I did some modifications after Dominique and Charles suggestions
      >> (Charles sent me a message off-list).
      >>
      >> The new circuit drawing is available here:
      >> http://www.geocities.com/mauricoma/mic_preamp_2.jpg
      >>
      >> I'm looking for a better IC and I will let you know.
      >>
      >> Thanks to all
      >>
      >> MAURIZIO
      >>
      >
    • Rui Antunes
      Can anyone tell me what is the input impedance of a ne5532 on this configuration?(non inverting) Just the input impedance of the op amp. Forgetting the voltage
      Message 2 of 10 , Apr 5 2:05 PM
      • 0 Attachment
        Can anyone tell me what is the input impedance of a ne5532 on this
        configuration?(non inverting)
        Just the input impedance of the op amp. Forgetting the voltage divider
        network.

        Another thing: how much current does the ne5532 draw operating at 9v?

        Thanks.

        On 4/5/07, Dominique M <ampgeek7@...> wrote:
        >
        > Welcome Nisios,
        >
        > I think the 1uF simply was a mistake.
        > Sometimes you find a (much smaller, and depending on the resistance)
        > capacitor at this place fo filter any unwanted high frequency (higher than
        >
        > audio) noise.
        >
        > Cheers,
        > Dominique
        >
        > ----- Original Message -----
        > From: "minimal_nisios" <nisios@... <nisios%40gmail.com>>
        > To: <micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com>>
        > Sent: Wednesday, April 04, 2007 8:04 PM
        > Subject: [micbuilders] Re: A very minimalist mic preamp from a rookie (a
        > new
        > drawing)
        >
        > >I have just finished my first mic. Its a XY stereo mic with a basic
        > > preamp inside the body for field recording, powered from a 9v battery.
        > > I made the pre amp from a text book and it is very similar to yours,
        > > the only difference being the abcense of the 1uF capacitor on the
        > > voltage divider. Can you tell me why you used that? What are the
        > > advantages?
        > > By the way this is the first time i write on this group. Im starting
        > > my electronics quest....so please have a bit of pacience with me:)
        > >
        > > Cheers to everyone.
        > > Nisios
        > >
        > > --- In micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com>,
        > "mauricoma" <maurizco@...> wrote:
        > >>
        > >> I did some modifications after Dominique and Charles suggestions
        > >> (Charles sent me a message off-list).
        > >>
        > >> The new circuit drawing is available here:
        > >> http://www.geocities.com/mauricoma/mic_preamp_2.jpg
        > >>
        > >> I'm looking for a better IC and I will let you know.
        > >>
        > >> Thanks to all
        > >>
        > >> MAURIZIO
        > >>
        > >
        >
        >
        >


        [Non-text portions of this message have been removed]
      • Dominique M
        Hi, is your name Rui? chama-se Rui? :) cause you signed the other post with nisios... You can find the devices datasheets at their sites: www.ti.com
        Message 3 of 10 , Apr 5 2:19 PM
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          Hi,

          is your name Rui?
          chama-se Rui? :)

          'cause you signed the other post with nisios...

          You can find the devices' datasheets at their sites:
          www.ti.com
          www.analog.com
          www.national.com
          www.maxim-ic.com
          www.linear.com

          just to mention those with the biggest choice of op-amps.
          I think that the NE5532 is originally made by Philips, now "NXP
          Semiconductors".
          TI, Fairchild, and probably others produce them also...

          The current it draws should be about 3mA per channel (together: 6mA)
          Input impedance is stated as 300kOhm (that's rather low for a chip like
          this).

          But the input impedance that the mic "sees" is that of the resistors, not of
          the op-amp.

          Cheers,
          Dominique

          ----- Original Message -----
          From: "Rui Antunes" <nisios@...>
          To: <micbuilders@yahoogroups.com>
          Sent: Thursday, April 05, 2007 11:05 PM
          Subject: Re: [micbuilders] Re: A very minimalist mic preamp from a rookie (a
          new drawing)


          > Can anyone tell me what is the input impedance of a ne5532 on this
          > configuration?(non inverting)
          > Just the input impedance of the op amp. Forgetting the voltage divider
          > network.
          >
          > Another thing: how much current does the ne5532 draw operating at 9v?
          >
          > Thanks.
          >
          > On 4/5/07, Dominique M <ampgeek7@...> wrote:
          >>
          >> Welcome Nisios,
          >>
          >> I think the 1uF simply was a mistake.
          >> Sometimes you find a (much smaller, and depending on the resistance)
          >> capacitor at this place fo filter any unwanted high frequency (higher
          >> than
          >>
          >> audio) noise.
          >>
          >> Cheers,
          >> Dominique
          >>
          >> ----- Original Message -----
          >> From: "minimal_nisios" <nisios@... <nisios%40gmail.com>>
          >> To: <micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com>>
          >> Sent: Wednesday, April 04, 2007 8:04 PM
          >> Subject: [micbuilders] Re: A very minimalist mic preamp from a rookie (a
          >> new
          >> drawing)
          >>
          >> >I have just finished my first mic. Its a XY stereo mic with a basic
          >> > preamp inside the body for field recording, powered from a 9v battery.
          >> > I made the pre amp from a text book and it is very similar to yours,
          >> > the only difference being the abcense of the 1uF capacitor on the
          >> > voltage divider. Can you tell me why you used that? What are the
          >> > advantages?
          >> > By the way this is the first time i write on this group. Im starting
          >> > my electronics quest....so please have a bit of pacience with me:)
          >> >
          >> > Cheers to everyone.
          >> > Nisios
          >> >
          >> > --- In micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com>,
          >> "mauricoma" <maurizco@...> wrote:
          >> >>
          >> >> I did some modifications after Dominique and Charles suggestions
          >> >> (Charles sent me a message off-list).
          >> >>
          >> >> The new circuit drawing is available here:
          >> >> http://www.geocities.com/mauricoma/mic_preamp_2.jpg
          >> >>
          >> >> I'm looking for a better IC and I will let you know.
          >> >>
          >> >> Thanks to all
          >> >>
          >> >> MAURIZIO
          >> >>
          >> >
          >>
          >>
          >>
          >
          >
          > [Non-text portions of this message have been removed]
          >
          >
          >
          >
          > Yahoo! Groups Links
          >
          >
          >
        • Rui Antunes
          Sim, chamo-me Rui. O meu nick é nisios mas como respondi directamente a partir do gmail apareceu o meu nome que esta associado a este email. Portugues? Sorry
          Message 4 of 10 , Apr 5 8:30 PM
          • 0 Attachment
            Sim, chamo-me Rui.
            O meu nick é nisios mas como respondi directamente a partir do gmail
            apareceu o meu nome que esta associado a este email.
            Portugues?

            Sorry you guys that doesn undestand what i just wrote....just asking if
            dominique is portuguese.....in portuguese.

            I might be wrong...but doesnt the non inverting amplifier configuration has
            a lot more impedance than the inverting one....in the order of the 50M? I
            think i have read this somewhere.


            On 4/5/07, Dominique M <ampgeek7@...> wrote:
            >
            > Hi,
            >
            > is your name Rui?
            > chama-se Rui? :)
            >
            > 'cause you signed the other post with nisios...
            >
            > You can find the devices' datasheets at their sites:
            > www.ti.com
            > www.analog.com
            > www.national.com
            > www.maxim-ic.com
            > www.linear.com
            >
            > just to mention those with the biggest choice of op-amps.
            > I think that the NE5532 is originally made by Philips, now "NXP
            > Semiconductors".
            > TI, Fairchild, and probably others produce them also...
            >
            > The current it draws should be about 3mA per channel (together: 6mA)
            > Input impedance is stated as 300kOhm (that's rather low for a chip like
            > this).
            >
            > But the input impedance that the mic "sees" is that of the resistors, not
            > of
            > the op-amp.
            >
            > Cheers,
            > Dominique
            >
            > ----- Original Message -----
            > From: "Rui Antunes" <nisios@... <nisios%40gmail.com>>
            > To: <micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com>>
            > Sent: Thursday, April 05, 2007 11:05 PM
            > Subject: Re: [micbuilders] Re: A very minimalist mic preamp from a rookie
            > (a
            > new drawing)
            >
            > > Can anyone tell me what is the input impedance of a ne5532 on this
            > > configuration?(non inverting)
            > > Just the input impedance of the op amp. Forgetting the voltage divider
            > > network.
            > >
            > > Another thing: how much current does the ne5532 draw operating at 9v?
            > >
            > > Thanks.
            > >
            > > On 4/5/07, Dominique M <ampgeek7@... <ampgeek7%40arcor.de>> wrote:
            > >>
            > >> Welcome Nisios,
            > >>
            > >> I think the 1uF simply was a mistake.
            > >> Sometimes you find a (much smaller, and depending on the resistance)
            > >> capacitor at this place fo filter any unwanted high frequency (higher
            > >> than
            > >>
            > >> audio) noise.
            > >>
            > >> Cheers,
            > >> Dominique
            > >>
            > >> ----- Original Message -----
            > >> From: "minimal_nisios" <nisios@... <nisios%40gmail.com><nisios%40gmail.com>>
            > >> To: <micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com><micbuilders%40yahoogroups.com>>
            > >> Sent: Wednesday, April 04, 2007 8:04 PM
            > >> Subject: [micbuilders] Re: A very minimalist mic preamp from a rookie
            > (a
            > >> new
            > >> drawing)
            > >>
            > >> >I have just finished my first mic. Its a XY stereo mic with a basic
            > >> > preamp inside the body for field recording, powered from a 9v
            > battery.
            > >> > I made the pre amp from a text book and it is very similar to yours,
            > >> > the only difference being the abcense of the 1uF capacitor on the
            > >> > voltage divider. Can you tell me why you used that? What are the
            > >> > advantages?
            > >> > By the way this is the first time i write on this group. Im starting
            > >> > my electronics quest....so please have a bit of pacience with me:)
            > >> >
            > >> > Cheers to everyone.
            > >> > Nisios
            > >> >
            > >> > --- In micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com><micbuilders%40yahoogroups.com>,
            > >> "mauricoma" <maurizco@...> wrote:
            > >> >>
            > >> >> I did some modifications after Dominique and Charles suggestions
            > >> >> (Charles sent me a message off-list).
            > >> >>
            > >> >> The new circuit drawing is available here:
            > >> >> http://www.geocities.com/mauricoma/mic_preamp_2.jpg
            > >> >>
            > >> >> I'm looking for a better IC and I will let you know.
            > >> >>
            > >> >> Thanks to all
            > >> >>
            > >> >> MAURIZIO
            > >> >>
            > >> >
            > >>
            > >>
            > >>
            > >
            > >
            > > [Non-text portions of this message have been removed]
            > >
            > >
            > >
            > >
            > > Yahoo! Groups Links
            > >
            > >
            > >
            >
            >
            >


            [Non-text portions of this message have been removed]
          • Rui Antunes
            What can i add to an amp like this to keep RF out? ... [Non-text portions of this message have been removed]
            Message 5 of 10 , Apr 7 11:00 PM
            • 0 Attachment
              What can i add to an amp like this to keep RF out?

              On 4/6/07, Rui Antunes <nisios@...> wrote:
              >
              > Sim, chamo-me Rui.
              > O meu nick é nisios mas como respondi directamente a partir do gmail
              > apareceu o meu nome que esta associado a este email.
              > Portugues?
              >
              > Sorry you guys that doesn undestand what i just wrote....just asking if
              > dominique is portuguese.....in portuguese.
              >
              > I might be wrong...but doesnt the non inverting amplifier configuration
              > has a lot more impedance than the inverting one....in the order of the 50M?
              > I think i have read this somewhere.
              >
              >
              > On 4/5/07, Dominique M <ampgeek7@...> wrote:
              > >
              > > Hi,
              > >
              > > is your name Rui?
              > > chama-se Rui? :)
              > >
              > > 'cause you signed the other post with nisios...
              > >
              > > You can find the devices' datasheets at their sites:
              > > www.ti.com
              > > www.analog.com
              > > www.national.com
              > > www.maxim-ic.com
              > > www.linear.com
              > >
              > > just to mention those with the biggest choice of op-amps.
              > > I think that the NE5532 is originally made by Philips, now "NXP
              > > Semiconductors".
              > > TI, Fairchild, and probably others produce them also...
              > >
              > > The current it draws should be about 3mA per channel (together: 6mA)
              > > Input impedance is stated as 300kOhm (that's rather low for a chip like
              > > this).
              > >
              > > But the input impedance that the mic "sees" is that of the resistors,
              > > not of
              > > the op-amp.
              > >
              > > Cheers,
              > > Dominique
              > >
              > > ----- Original Message -----
              > > From: "Rui Antunes" <nisios@... <nisios%40gmail.com>>
              > > To: <micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com>>
              > > Sent: Thursday, April 05, 2007 11:05 PM
              > > Subject: Re: [micbuilders] Re: A very minimalist mic preamp from a
              > > rookie (a
              > > new drawing)
              > >
              > > > Can anyone tell me what is the input impedance of a ne5532 on this
              > > > configuration?(non inverting)
              > > > Just the input impedance of the op amp. Forgetting the voltage divider
              > > > network.
              > > >
              > > > Another thing: how much current does the ne5532 draw operating at 9v?
              > > >
              > > > Thanks.
              > > >
              > > > On 4/5/07, Dominique M <ampgeek7@... <ampgeek7%40arcor.de>>
              > > wrote:
              > > >>
              > > >> Welcome Nisios,
              > > >>
              > > >> I think the 1uF simply was a mistake.
              > > >> Sometimes you find a (much smaller, and depending on the resistance)
              > > >> capacitor at this place fo filter any unwanted high frequency (higher
              > >
              > > >> than
              > > >>
              > > >> audio) noise.
              > > >>
              > > >> Cheers,
              > > >> Dominique
              > > >>
              > > >> ----- Original Message -----
              > > >> From: "minimal_nisios" <nisios@... <nisios%40gmail.com><nisios%40gmail.com>>
              > > >> To: <micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com><micbuilders%40yahoogroups.com>>
              > > >> Sent: Wednesday, April 04, 2007 8:04 PM
              > > >> Subject: [micbuilders] Re: A very minimalist mic preamp from a rookie
              > > (a
              > > >> new
              > > >> drawing)
              > > >>
              > > >> >I have just finished my first mic. Its a XY stereo mic with a basic
              > > >> > preamp inside the body for field recording, powered from a 9v
              > > battery.
              > > >> > I made the pre amp from a text book and it is very similar to
              > > yours,
              > > >> > the only difference being the abcense of the 1uF capacitor on the
              > > >> > voltage divider. Can you tell me why you used that? What are the
              > > >> > advantages?
              > > >> > By the way this is the first time i write on this group. Im
              > > starting
              > > >> > my electronics quest....so please have a bit of pacience with me:)
              > > >> >
              > > >> > Cheers to everyone.
              > > >> > Nisios
              > > >> >
              > > >> > --- In micbuilders@yahoogroups.com <micbuilders%40yahoogroups.com><micbuilders%40yahoogroups.com>,
              > > >> "mauricoma" <maurizco@...> wrote:
              > > >> >>
              > > >> >> I did some modifications after Dominique and Charles suggestions
              > > >> >> (Charles sent me a message off-list).
              > > >> >>
              > > >> >> The new circuit drawing is available here:
              > > >> >> http://www.geocities.com/mauricoma/mic_preamp_2.jpg
              > > >> >>
              > > >> >> I'm looking for a better IC and I will let you know.
              > > >> >>
              > > >> >> Thanks to all
              > > >> >>
              > > >> >> MAURIZIO
              > > >> >>
              > > >> >
              > > >>
              > > >>
              > > >>
              > > >
              > > >
              > > > [Non-text portions of this message have been removed]
              > > >
              > > >
              > > >
              > > >
              > > > Yahoo! Groups Links
              > > >
              > > >
              > > >
              > >
              > >
              > >
              >
              >


              [Non-text portions of this message have been removed]
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