Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
I have a circuit for an ECM preamp but the microphone in the circuit has
three pins. The only types I can get hold of are the 2 pin variety. Is
there
an easy way to convert the circuit so that I can use a 2 pin electret?
Thanks
Andrew Howard
Where is the schem? I think that the 3 pin variety has 1 pin for ground, 1
for signal, and 1 for V+. The 2 pin kind has 1 for ground, and the signal
and V+ is shared by the 2nd pin. The signal output must use a DC blocking
cap between it and the amp in.
"Andrew Howard" <andtfoot@HotPOP.com> wrote in message
news:FFZYa.21872$bo1.20997@news-server.bigpond.net.au...
I have a circuit for an ECM preamp but the microphone in the circuit has
three pins. The only types I can get hold of are the 2 pin variety. Is
there
an easy way to convert the circuit so that I can use a 2 pin electret?
Thanks
Andrew Howard
The schematic is located at:
http://www.mitedu.freeserve.co.uk/Circuits/Audio/ecmmic.html
I think it me be as you described it, but if so, do you know how to use
the
2 pinned type with the circuit?
Failing this, if you could direct me to any good electret microphone
preaamp
circuit for ecms with 2 pins, I would be grateful.
Thankyou
Andrew Howard
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:SS9Za.18103$x04.317@nntp-post.primus.ca...
Where is the schem? I think that the 3 pin variety has 1 pin for ground,
1
for signal, and 1 for V+. The 2 pin kind has 1 for ground, and the
signal
and V+ is shared by the 2nd pin. The signal output must use a DC
blocking
cap between it and the amp in.
"Andrew Howard" <andtfoot@HotPOP.com> wrote in message
news:FFZYa.21872$bo1.20997@news-server.bigpond.net.au...
I have a circuit for an ECM preamp but the microphone in the circuit
has
three pins. The only types I can get hold of are the 2 pin variety. Is
there
an easy way to convert the circuit so that I can use a 2 pin electret?
Thanks
Andrew Howard
The schematic is located at:
http://www.mitedu.freeserve.co.uk/Circuits/Audio/ecmmic.html
I think it me be as you described it, but if so, do you know how to use the
2 pinned type with the circuit?
Failing this, if you could direct me to any good electret microphone preaamp
circuit for ecms with 2 pins, I would be grateful.
Thankyou
Andrew Howard
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:SS9Za.18103$x04.317@nntp-post.primus.ca...
Where is the schem? I think that the 3 pin variety has 1 pin for ground, 1
for signal, and 1 for V+. The 2 pin kind has 1 for ground, and the signal
and V+ is shared by the 2nd pin. The signal output must use a DC blocking
cap between it and the amp in.
"Andrew Howard" <andtfoot@HotPOP.com> wrote in message
news:FFZYa.21872$bo1.20997@news-server.bigpond.net.au...
I have a circuit for an ECM preamp but the microphone in the circuit has
three pins. The only types I can get hold of are the 2 pin variety. Is
there
an easy way to convert the circuit so that I can use a 2 pin electret?
Thanks
Andrew Howard
All you have to do is use a blocking cap from the output of the mic to
prevent sending the DC supply voltage to the preamp. The schematic you've
pointed to has a 10uF cap between the output of the mic and the base of
the
transistor, so that will do the job. So, the only adjustment that you need
to make is to connect the 1K resistor to the same mic pin as the 10uF cap.
IOW, connect the top pin of the mic in the schem to the middle pin, and
that
will be the same as the 2 pin ecm that you have. Make sure that the cap is
on the transistor side of the resistor, though, so it blocks the DC (like
it
is in the schem).
One caveat - I notice the whole thing is powered by a 12v supply. Most of
these types of ecms recommend a 2-10v supply voltage (oddly, it even says
so
in the article). You may want to either use a regulator to drop the mic
supply voltage down to 9v, or use a simple voltage divider. Keep in mind
though, that the 1k resistor effectively sets the output Z; this will
change
if you use either the regulator or the divider method.
One other thought - these ECMs can be had very cheap (I'm asuming you're
not
using an expensive element here) so you might want to just go ahead and
try
it with 12v, and see if it works OK. Where are you getting your mic
element
from?
"Andrew Howard" <andtfoot@HotPOP.com> wrote in message
news:RIaZa.24562$bo1.24108@news-server.bigpond.net.au...
The schematic is located at:
http://www.mitedu.freeserve.co.uk/Circuits/Audio/ecmmic.html
I think it me be as you described it, but if so, do you know how to use
the
2 pinned type with the circuit?
Failing this, if you could direct me to any good electret microphone
preaamp
circuit for ecms with 2 pins, I would be grateful.
Thankyou
Andrew Howard
"tempus fugit" <toccata.no.spam@ciaccess.com> wrote in message
news:SS9Za.18103$x04.317@nntp-post.primus.ca...
Where is the schem? I think that the 3 pin variety has 1 pin for
ground,
1
for signal, and 1 for V+. The 2 pin kind has 1 for ground, and the
signal
and V+ is shared by the 2nd pin. The signal output must use a DC
blocking
cap between it and the amp in.
"Andrew Howard" <andtfoot@HotPOP.com> wrote in message
news:FFZYa.21872$bo1.20997@news-server.bigpond.net.au...
I have a circuit for an ECM preamp but the microphone in the circuit
has
three pins. The only types I can get hold of are the 2 pin variety.
Is
there
an easy way to convert the circuit so that I can use a 2 pin
electret?
Thanks
Andrew Howard