# microphone preamp

A

#### [email protected]

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated, since I can sustain without problem
reasonable amounts of noise and distortion.

Thanks!

Alessandro Magni

E

#### Eeyore

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room)

At what volume level roughly ? Similar to ordinary speech for example or much
quieter ?

with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated, since I can sustain without problem
reasonable amounts of noise and distortion.

What kind of microphone ?

The cheap type that plugs into your PC soundcard or a 'decent' low impedance
balanced one ?

Graham

F

#### [email protected]

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated, since I can sustain without problem
reasonable amounts of noise and distortion.

Thanks!

Alessandro Magni

hi
i don't know from which place ur from, if ur in Bangalore, visit to SP
road were u find all types of electronics gadgets, if ur in any other
places visit to ur near places were all types of electronics goods are
sold and serviced,
when u go there ask for VEGA KITS booklets, in which u find all type of
electronics project for beginner and expert using this project u will
improve ur skill in electronics

there many types of microphone preamp,
1. type of microphone,
2. type of enviroment
3. economy circuit
all this is available in VEGA KITS try this out or log on to
WWW.VEGAKITS.COM, and build ur own circuits

take care when assembling components

A

#### Ancient_Hacker

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard.

What is the problem:

(1) Is the recorded sound too weak?

(2) Is there too much background noise in the recording?

(3) Is there too much echo in the recording?

(4) Is there too much bass or too much treble?

(5) All the voices sound like xylon robots?

(6) One or more of the above?

A

#### [email protected]

Jan 1, 1970
0
Eeyore said:
What kind of microphone ?
The cheap type that plugs into your PC soundcard or a 'decent' low impedance balanced one ?

the cheap one!

Ancient_Hacker ha scritto:
What is the problem:

(1) Is the recorded sound too weak?

(2) Is there too much background noise in the recording?

(3) Is there too much echo in the recording?

(4) Is there too much bass or too much treble?

(5) All the voices sound like xylon robots?

(6) One or more of the above?

the problem is (1): recorded sound almost inaudible [on the software
side the rec levels seem to be allo OK]

E

#### Eeyore

Jan 1, 1970
0
the cheap one!

OK. Electret presumably ?

Ancient_Hacker ha scritto:
What is the problem:

(1) Is the recorded sound too weak?

(2) Is there too much background noise in the recording?

(3) Is there too much echo in the recording?

(4) Is there too much bass or too much treble?

(5) All the voices sound like xylon robots?

(6) One or more of the above?

the problem is (1): recorded sound almost inaudible [on the software
side the rec levels seem to be allo OK]

I don't quite follow.

When recording do you have a decent recording level on whatever meteting your sound application
provides ?

When playing back, is the wanted sound inaudible in a sea of hiss ?

Graham

P

#### Phil Allison

Jan 1, 1970
0
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated,

** See:

http://sound.westhost.com/project66.htm

Provided you have a decent balanced dynamic mic and not a POS electret
capsule.

........ Phil

J

#### John B

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a
begginer)? I don't need anything complicated, since I can sustain
without problem reasonable amounts of noise and distortion.

Thanks!

Alessandro Magni

A PC sound card is designed to work with an electret mic. You are
probably using a dynamic mic.

Try typing "microphone amplifier" into Google, It's amazing what turns
up.

D

#### D from BC

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated, since I can sustain without problem
reasonable amounts of noise and distortion.

Thanks!

Alessandro Magni

Maybe try:
http://www.linearx.com/products/microphones/m53/M53_1.htm
Just power it up with 10Volts..
Just something left over from my audiophool days

D from BC

A

#### Ancient_Hacker

Jan 1, 1970
0
the problem is (1): recorded sound almost inaudible [on the software
side the rec levels seem to be allo OK]

Well, this is puzzling. If the record levels, as shown on the "VU
Meters", are okay, then the recording should be okay.

How about you post the audio file somewhere where we can all listen to
it?

R

#### Rich Grise

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated, since I can sustain without problem
reasonable amounts of noise and distortion.

I built one of these once, albeit I don't remember the component values
exactly:
http://www.ecircuitcenter.com/Circuits/trce/trce.htm

It was a Radio Shack dynamic, marked "600 ohms", for what that's worth.

It boosted the mic so that the sound card could "hear" it. One difference
is, I dropped RL, replaced RC with a pot, and connected CL to the pot's
wiper, then went right from CL to the sound card input.

Good Luck!
Rich

J

#### jasen

Jan 1, 1970
0
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated, since I can sustain without problem
reasonable amounts of noise and distortion.

I found this helped with a 600 ohm microphone.

tip ---------+-[4m7]-.
| |
\ |
0.1uF \| | || 2.2uF
|----+-||--------.
|/| || \_ |
/~ BC547 ( )|
| /~ |
sleeve ------+-------------------'

1 simple
2 draws power from the soundcard

1 performance varies from mediocre to bad
depending on parts and temperature

try differemt resistors 3.3M 3.9M 5.6M etc

.-------------------------------------------------------------.
| This is an ascii schematic, if the diagram appears garbled |
| try switching to a fixed-pitch font (courier works well) |
| pasting it into notepad works well on ms-windows. |
| in google groups selecting 'fixed font' (top right of page) |
| or view source (options) work too. |
-------------------------------------------------------------'

A

#### [email protected]

Jan 1, 1970
0
jasen ha scritto:
Hello,
I need to record sound coming from a large space (a room) with a
microphone connected to a PC soundcard. So far the results have been
disappointing, and I've been suggested that I need to preamp the
microphone.
Can you kindly suggest a <VERY SIMPLE> circuit design (I'm a begginer)?
I don't need anything complicated, since I can sustain without problem
reasonable amounts of noise and distortion.

I found this helped with a 600 ohm microphone.

tip ---------+-[4m7]-.
| |
\ |
0.1uF \| | || 2.2uF
|----+-||--------.
|/| || \_ |
/~ BC547 ( )|
| /~ |
sleeve ------+-------------------'

1 simple
2 draws power from the soundcard

1 performance varies from mediocre to bad
depending on parts and temperature

try differemt resistors 3.3M 3.9M 5.6M etc

.-------------------------------------------------------------.
| This is an ascii schematic, if the diagram appears garbled |
| try switching to a fixed-pitch font (courier works well) |
| pasting it into notepad works well on ms-windows. |
| in google groups selecting 'fixed font' (top right of page) |
| or view source (options) work too. |
-------------------------------------------------------------'

Hi Jasen - thanks for your help!
One problem only, I'm slightly confused on the diagram (even reading
it at fixed-width):
1) the component labeled 4m7 is a 4.7 mOhm resistence?
2) I see the label 0.1uF but I dont see the condenser in the drawing!
3) the "thing" at the right represents the soundcard?
4) your comment " try differemt resistors 3.3M 3.9M 5.6M etc" meaning
in place of the 4.7 milliOhm?

.... sorry, but as I told before, I'm not exactly a great-master in
electronics!

Alessandro

J

#### jasen

Jan 1, 1970
0
jasen ha scritto:

Hi Jasen - thanks for your help!
One problem only, I'm slightly confused on the diagram (even reading
it at fixed-width):
1) the component labeled 4m7 is a 4.7 mOhm resistence?

oops! should be a big M there 4.7M Ohm resistance.
2) I see the label 0.1uF but I dont see the condenser in the drawing!

that was an accident in editing, there is no second condenser.
ignore that.
3) the "thing" at the right represents the soundcard?

that's meant to be the microphone.
4) your comment " try differemt resistors 3.3M 3.9M 5.6M etc" meaning
in place of the 4.7 milliOhm?

Sorry, as above, that was intended as megaohm.

Revision 2: (use fixed-pitch font)

tip ---------+-[4M7]-.
| |
\ |
\| | +|| 2.2uF
soundcard |----+----||------------.
mic socket |/| || \_ |
/~ BC547 ( )| mic
| /~ |
sleeve ------+--------------------------'

Bye.
Jasen

R

#### Rich Grise

Jan 1, 1970
0
Revision 2: (use fixed-pitch font)

tip ---------+-[4M7]-.
| |
\ |
\| | +|| 2.2uF
soundcard |----+----||------------.
mic socket |/| || \_ |
/~ BC547 ( )| mic
| /~ |
sleeve ------+--------------------------'

You've drawn this backwards! It should be:

.-[4M7]-+--------- tip
| |
| /
2.2uF ||+ | |/
.------------||----+----| soundcard
| _/ || |\| mic socket
mic |( ) BC547 ~\
| ~\ |
'--------------------------+------ sleeve

The signal should go from left to right, just like we read.

Cheers!
Rich

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