[izms]

First and foremost, I am no electrical engineer, a far cry from it
actually. Years ago I assembled a DIY electret condenser microphone
with external power supply using a 9V battery and loved its
performance. I am curious if there are any power converters small
enough to convert 48V down to 9V or less, that way I could eliminate
the external supply and have the element and converter in one assembly
(like a standard pencil condenser microphone). The key here is to
eliminate the bulk and keep the microphone as small as possible.

Any ideas would be greatly appreciated. Thanks!

[Arny Krueger]

"izms" wrote in message

First and foremost, I am no electrical engineer, a far
cry from it actually. Years ago I assembled a DIY
electret condenser microphone with external power supply
using a 9V battery and loved its performance. I am
curious if there are any power converters small enough to
convert 48V down to 9V or less, that way I could
eliminate the external supply and have the element and
converter in one assembly (like a standard pencil
condenser microphone). The key here is to eliminate the
bulk and keep the microphone as small as possible.

Any ideas would be greatly appreciated. Thanks!

If you want to convert 48 volts to 9, it is a pretty simple problem.

http://hyperphysics.phy-astr.gsu.edu...c/zenereg.html

[Richard Crowley]

"izms" wrote ...
First and foremost, I am no electrical engineer, a far cry from it
actually. Years ago I assembled a DIY electret condenser microphone
with external power supply using a 9V battery and loved its
performance. I am curious if there are any power converters small
enough to convert 48V down to 9V or less, that way I could eliminate
the external supply and have the element and converter in one assembly
(like a standard pencil condenser microphone). The key here is to
eliminate the bulk and keep the microphone as small as possible.

There are many circuits for interfacing electret capsules to balanced
mic lines and powering the whole thing with phantom power. Most of
these circuits are likely out on the internet. A couple good places to
start are Rick Chinn's website (http://www.uneeda-audio.com/) and
the Micbuilders group on Yahoo Groups.
http://tech.groups.yahoo.com/group/micbuilders

Most of them are variations on this theme (active) ...
http://www.scotthelmke.com/phantom-power-2.jpg
Or this one (passive)...
http://www.ka-electronics.com/DC_Pre...t_Internal.jpg

[Trevor Wilson[_3_]]

Arny Krueger wrote:
"izms" wrote in message

First and foremost, I am no electrical engineer, a far
cry from it actually. Years ago I assembled a DIY
electret condenser microphone with external power supply
using a 9V battery and loved its performance. I am
curious if there are any power converters small enough to
convert 48V down to 9V or less, that way I could
eliminate the external supply and have the element and
converter in one assembly (like a standard pencil
condenser microphone). The key here is to eliminate the
bulk and keep the microphone as small as possible.

Any ideas would be greatly appreciated. Thanks!

If you want to convert 48 volts to 9, it is a pretty simple problem.

http://hyperphysics.phy-astr.gsu.edu...c/zenereg.html

**A zener regulator may exhibit far too much noise for such an application.
Much better to use a proper low noise regulator, possibly based on a LM317 +
high Voltage pass transistor. Bigger and more complex, but far lower noise
levels. In fact, I've built a few such regulators (for reducing phantom
power to 9 or 12 Volts) and enjoyed great success. Due to the very low
currents, the whole lot can be assembled on a small PCB and contained within
ehat shrink.


--
Trevor Wilson
www.rageaudio.com.au


--
Trevor Wilson
www.rageaudio.com.au