Off topic - audio circuit design
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Posts: 46,084
Sorry for cluttering the list with off topic queries but...
Part of my (stamp based) project requires a microphone input to the
analog inputs of a VCR. Right now I'm buying a preamplified
microphone which works fine but it's a little pricey and I'd like to
integrate the circuit on the same board as the stamp. The problem is
that digital electronics is hard enough for me. Analog stuff blows
what little is left of my mind. Can anyone point me to some
straightforward info on building a condenor mic/preamp/volume control
with an output that would interface properly with the vcr input (I
think the VCR is looking for 1vP-P).
Thanks in advance
Duncan Potter
Part of my (stamp based) project requires a microphone input to the
analog inputs of a VCR. Right now I'm buying a preamplified
microphone which works fine but it's a little pricey and I'd like to
integrate the circuit on the same board as the stamp. The problem is
that digital electronics is hard enough for me. Analog stuff blows
what little is left of my mind. Can anyone point me to some
straightforward info on building a condenor mic/preamp/volume control
with an output that would interface properly with the vcr input (I
think the VCR is looking for 1vP-P).
Thanks in advance
Duncan Potter
Comments
>straightforward info on building a condenor mic/preamp/volume control
>with an output that would interface properly with the vcr input (I
>think the VCR is looking for 1vP-P).
Coincidently, I was just looking at one:
http://members.tripod.com/~schematics/stereo.htm
Carl
pot for volume control.
Dennis
Original Message
From: diacon1208 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=lPzFNR9TI_GW8-J8VlSLDYSm21OnMoJ1raKhD4RIlzSvY9C6UkgkUFk4smnWT3U9w5KNSL2pJahSJHE1lnW77g]dpotter@d...[/url
Sent: Thursday, January 31, 2002 4:35 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Off topic - audio circuit design
Analog stuff blows
what little is left of my mind. Can anyone point me to some
straightforward info on building a condenor mic/preamp/volume control
with an output that would interface properly with the vcr input (I
think the VCR is looking for 1vP-P).
I think a single NPN common variety (2N3904) transistor amplifier
biased with a 220K or so resistor across the base-collector and
10K or so pull-up to V+ with a 10uF capacitor on the output should
do the trick. A pot with the center leg placed on the Transistor
Base, one pot leg going to GND and the other pot leg used as a
signal source makes a simple wide range volume control.
However, you will still need to provide phantom power to the
condenser mic if using a LM386 or a single transistor.
Phantom power for a condenser mic:
Note: Some VCR's might be able to handle the output of the circuit
below without any problem. Others will need the Transistor
amplifier described above.
capacitor (0.5 uf or so)
| |
+
+
| |
> to pre-amp
| | | |
| (positive lead) | _ _
| +
/ \_/ \_/
+
MIC (resistor 1-2K or so) |
| | +
| (ground lead) (-)
| (battery 9v or so) ---
| |
| |
+
+----> ground
to amp
>I use a LM386-N for a single-chip, about 1W, preamp, along with a 10K
>pot for volume control.
>
>Dennis
>
>
Original Message
>From: diacon1208 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=D_SqFDlR9LYVzFivpzfv7FQPeyXF9wVlMCp6FX9DYu8Nj6g7FIo8StJT5RtUBKCL4RpwFutZ4csEZJkgOBeWuw]dpotter@d...[/url
>Sent: Thursday, January 31, 2002 4:35 PM
>To: basicstamps@yahoogroups.com
>Subject: [noparse][[/noparse]basicstamps] Off topic - audio circuit design
>
>Analog stuff blows
>what little is left of my mind. Can anyone point me to some
>straightforward info on building a condenor mic/preamp/volume control
>with an output that would interface properly with the vcr input (I
>think the VCR is looking for 1vP-P).
Beau Schwabe Mask Designer IV - ATL
National Semiconductor Wired Communications Division
500 Pinnacle Court, Suite 525 Mail Stop GA1 Norcross, GA 30071
Robert Staph, W3RCS
The Center for Advanced Technologies
Original Message
From: "Dennis P. O'Leary" <doleary@h...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, February 01, 2002 2:37 PM
Subject: RE: [noparse][[/noparse]basicstamps] Off topic - audio circuit design
> I use a LM386-N for a single-chip, about 1W, preamp, along with a 10K
> pot for volume control.
>
> Dennis
>
>
Original Message
> From: diacon1208 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=uRZacmgdEwJENr7rY8L32dM-Ik0QRfHy77YxcDAFzj--CGVQMd3Cww79UEie089MxjXSIBm-6EaFsu_xOu3n]dpotter@d...[/url
> Sent: Thursday, January 31, 2002 4:35 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Off topic - audio circuit design
>
> Analog stuff blows
> what little is left of my mind. Can anyone point me to some
> straightforward info on building a condenor mic/preamp/volume control
> with an output that would interface properly with the vcr input (I
> think the VCR is looking for 1vP-P).
>
>
> To UNSUBSCRIBE, just send mail to:
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>
>
I use the schematic in Radio Shack's "Semiconductor Reference Guide",
1992 edition. If you don't have access to one, send me your FAX number
off-list.
BTW, Beau's simpler circuit looks fine to me for a VCR input. My
application uses a small speaker on a PC board to deliver audio tones.
Dennis
Original Message
From: Robert Staph [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=YpEaZRRghpDCG81iiTPQ4pDdGH2Jnq0DK_DC9zaxGhSAKLbSzkqAl0Udv-PPnYDEmixmJVSXc6Qs_g]rstaph@a...[/url
Sent: Friday, February 01, 2002 12:22 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Off topic - audio circuit design
You wouldn't happen to have a link to an schematics on that would you?
Robert Staph, W3RCS
The Center for Advanced Technologies
Original Message
From: "Dennis P. O'Leary" <doleary@h...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, February 01, 2002 2:37 PM
Subject: RE: [noparse][[/noparse]basicstamps] Off topic - audio circuit design
> I use a LM386-N for a single-chip, about 1W, preamp, along with a 10K
> pot for volume control.
>
> Dennis
>
>
Original Message
> From: diacon1208 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=dKj7CwUJqj6M-_G5buR3d3aHukhY8hSabq6MetBtyLRPfcMZkwh-sYPJuSRSpmAOdMXVt_H9sXOPWxglhJc]dpotter@d...[/url
> Sent: Thursday, January 31, 2002 4:35 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Off topic - audio circuit design
>
> Analog stuff blows
> what little is left of my mind. Can anyone point me to some
> straightforward info on building a condenor mic/preamp/volume control
> with an output that would interface properly with the vcr input (I
> think the VCR is looking for 1vP-P).
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
> and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
Your use of Yahoo! Groups is subject to
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