Maker Pro
Maker Pro

condenser mic - rewire/convert 1/8" to XLR?

M

Mad Scientist Jr

Jan 1, 1970
0
I have a couple of electret condenser mics (Radio Shack Cat. No.
33-1060 or similar) that run off a AAA battery and have a 1/8" plug.
Is it possible to rewire these to accept XLR cables instead for
increased signal strength? How?
Thanks...
 
K

Keith Adams

Jan 1, 1970
0
An XLR plug will only make a balanced signal and more clarity but not
hotter. You need to have a 3 conductor cord coming from the mic.
If it has that then yes .Just wire up the plug. You need to make sure which
pin is hot and put a jumper from the body ground on the XLR plug to the
ground wire pin on it as well. The body ground is the screw that tightens
the plug end to the metal body. The plastic solderless type are a bit
different but you can figure it out when you get inside it.
If your mic now has a 1/4" jack on it then its probably 2 conductor and
I've put un needed miles on my typing finger for nothing.
 
M

Mad Scientist Jr

Jan 1, 1970
0
Thanks for your reply.

I'm not sure how many conductors it has, I think it has 2 hot and 2
ground, but I will have to open it up to make sure.

Let me clarify my question though - say you have the following circuit
-

http://www.electronicsteacher.com/circuits-and-diagrams/audio-preamp-circuits/preamp.gif

with a microphone attached. What modifications would you do to *make*
it a 3-conductor connection for XLR? Because I am also building some
microphones with that preamp circuit and would like them to have XLR
connectors.

Thanks again...
 
S

sycochkn

Jan 1, 1970
0
Mad Scientist Jr said:
I have a couple of electret condenser mics (Radio Shack Cat. No.
33-1060 or similar) that run off a AAA battery and have a 1/8" plug.
Is it possible to rewire these to accept XLR cables instead for
increased signal strength? How?
Thanks...

Transformer.
 
M

Mad Scientist Jr

Jan 1, 1970
0
Thanks for the reply - what kind of transformer? How do you wire it
up? Is there a good schematic online how to do this?
 
S

sycochkn

Jan 1, 1970
0
Mad Scientist Jr said:
Thanks for the reply - what kind of transformer? How do you wire it
up? Is there a good schematic online how to do this?

High impedence to low impedence microphone transformer. It will probably
have a 1/4 input and and XLR output. or you could get a seperate transformer
and mount it in your preamp.

Bob
 
K

Keith Adams

Jan 1, 1970
0
You cant get more signal strength from the mic element.
Only from the preamp. You should actually give up on your current plan and
buy some better mics. An electret mic element due to its being active
usually puts out a very hot signal by its self. Along the lines of -35db. A
very very hot dynamic or crystal will only produce a measly -50db in
comparisson. A dynamic at -50db hooked to a high impedence transformer and
into a guitar amp will overdrive the holy hell out of it even at low volume.
High volume and the amp will go into run away feedback. If your mics are
presently using a 1/4" plug on the end of the cord then they're more than
likely 2 conductor and toy microphones. If you want an XLR plug on them
there will be no improvement in the mics performance but buy an adaptor for
1/4" to XLR. I really think you need to do more research on the subject
though.
 
K

Keith Adams

Jan 1, 1970
0
What is it exactly that you want to accomplish besides having an XLR plug
on your mics? Are you by chance trying to make a hot harp mic?
 
T

tempus fugit

Jan 1, 1970
0
Mad Scientist Jr said:
Thanks for the reply - what kind of transformer? How do you wire it
up? Is there a good schematic online how to do this?
I'd just use these:

http://karmaaudio.com/kmicro.html

For $10 apiece, you cant really go wrong - it's all wired up for you and the
XLR is already there..
 
D

David Martel

Jan 1, 1970
0
Mad,

There's a fellow named Forrest Mims III who is quite famous for his
ability to write readable introductions to various sub-specialties of
electronics. Radio Shack used to sell some of his audio books. Your local
library should also have his books.
As others have said, rewiring your cable for an xlr plug will not
increase your signal strength. By putting a transformer in line with your
mic output you can convert from unbalanced high impedance to balanced low
impedance. It's not clear why you want to do this.
If you want to learn electronics perhaps the local tech school has a
course or two. Book learning will not help you when you need to use a
soldering iron and punch or drill holes

Dave M.
 
M

Mad Scientist Jr

Jan 1, 1970
0
Thanks for your reply. This mic isn't going into a guitar amp, it
would go into a mixing board for recording.
 
M

Mad Scientist Jr

Jan 1, 1970
0
An inexpensive way to make/modify some nice sensitive condenser mics
to record with.
 
M

Mad Scientist Jr

Jan 1, 1970
0
Pretty cool - btw what is the difference between buying a matched pair
and just buying two of the same mic?
Thanks for the link!
 
M

Mad Scientist Jr

Jan 1, 1970
0
PS this would be for omnidirectional mics, so those $10 xlr mics from
karmaaudio probably wouldn't work for replacing these. If it's
possible to wire them to XLR without too much trouble or cost then I
would just like to try it. A mic going into an XLR input has more dB
than a mic going into a 1/4" input.
 
E

Eeyore

Jan 1, 1970
0
Mad said:
I have a couple of electret condenser mics (Radio Shack Cat. No.
33-1060 or similar) that run off a AAA battery and have a 1/8" plug.
Is it possible to rewire these to accept XLR cables instead for
increased signal strength? How?

It won't affect their 'signal strength'.

Graham
 
Top