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

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  • 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 1 of 10 , Apr 5 2:05 PM
      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 2 of 10 , Apr 5 2:19 PM
        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 3 of 10 , Apr 5 8:30 PM
          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 4 of 10 , Apr 7 11:00 PM
            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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