Using old microphone on PC

T

Terry Pinnell

Guest
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

--
Terry, East Grinstead, UK
 
Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?
Click to expand...
Short answer is it can't be done.

Longer answer: Firstly, you'll need a several microfarad capacitor in
series with the signal line to isolate it, otherwise the PC input
circuitry will try to feed it power. You might be able to get away
without it, but turns out that's the LEAST of your problems.

You'll serious amounts of gain. Your Dynamic mic outputs less signal
than a typical electret mic that would otherwise be used with a PC, so
even full blast, you'll *just* be able to hear it while yelling.
Certainly not viable, anyway.

Short of a pre-amplifier that's not going to happen, and since a
pre-amp isn't "Simplest" it can't be done to your requirements.
--
It's not the principle of the thing, it's the money
 
On Tue, 20 Sep 2011 10:29:05 +0100, Terry Pinnell
<terrypingm@DELETEgmail.com> wrote:

In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?
Click to expand...
---
Microphone transformer:

http://www.google.com/products/catalog?q=microphone+transformer&hl=en&prmd=imvns&bav=on.2,or.r_gc.r_pw.&biw=1280&bih=814&wrapid=tlif131651472395510&um=1&ie=UTF-8&tbm=shop&cid=8705588807110651835&sa=X&ei=qmt4TvyJJ6itsAKz-_StDQ&ved=0CJYBEPMCMAA#

--
JF
 
"Globemaker"


The low impedance microphone needs a transformer to make it have high
impedance.

** Bad advice.

Mic inputs on PCs are not high impedance.


..... Phil
 
On Sep 20, 5:29 am, Terry Pinnell <terrypi...@DELETEgmail.com> wrote:
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

--
Terry, East Grinstead, UK
Click to expand...
The low impedance microphone needs a transformer to make it have high
impedance. Go to a guitar store and buy one for $20. It has 3 holes on
one end for XLR low Z and one the other end it has a 1/4 inch phone
jack like a guitar cord.
 
Globemaker <alanfolmsbee@cabanova.com> wrote:

On Sep 20, 5:29 am, Terry Pinnell <terrypi...@DELETEgmail.com> wrote:
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

--
Terry, East Grinstead, UK

The low impedance microphone needs a transformer to make it have high
impedance. Go to a guitar store and buy one for $20. It has 3 holes on
one end for XLR low Z and one the other end it has a 1/4 inch phone
jack like a guitar cord.
Click to expand...
Thanks all. That inexpensive transformer looks ideal, but so far not found
a UK source.

I do have a few miscellaneous audio transformers, so in parallel with more
googling maybe I'll experiment. It'll get me away from the PC for a while
anyway ;-)

--
Terry, East Grinstead, UK
 
"Terry Pinnell" <terrypingm@DELETEgmail.com> wrote in message
news:6tmg775oa5gsc39fhp6ar4t83l04akmfba@4ax.com...
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

--
Terry, East Grinstead, UK
Click to expand...
http://www.videotexsystems.com/product.php?productid=15798
 
"Terry Pinnell" <terrypingm@DELETEgmail.com> wrote in message
news:6tmg775oa5gsc39fhp6ar4t83l04akmfba@4ax.com...
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?
Click to expand...
Simple circuits for the casual audio electronics people
http://www.hobby-hour.com/electronics/computer_microphone.php
 
"bw" <bwegher@hotmail.com> wrote:

"Terry Pinnell" <terrypingm@DELETEgmail.com> wrote in message
news:6tmg775oa5gsc39fhp6ar4t83l04akmfba@4ax.com...
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?


Simple circuits for the casual audio electronics people
http://www.hobby-hour.com/electronics/computer_microphone.php

Thanks, useful article. May well get me back into my shed!
Click to expand...

But as for
http://www.videotexsystems.com/product.php?productid=15798
at $100 (plus international delivery) I'll pass thanks ;-)

--
Terry, East Grinstead, UK
 
On Tue, 20 Sep 2011 10:29:05 +0100, Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality
mic, a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It
proved useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?
Click to expand...
What _are_ the specs for a typical PC microphone input port? And are
there even specs, or does the circuit just happen to be what the
manufacturer felt like using at the time?

I gather that it's designed for electret microphones, then -- that makes
lots of sense. In theory that means that you could make a preamp that
would be powered by the PC, but that's only "simplest" if you have a well-
stocked junkbox, some knowledge, and some time.

--
www.wescottdesign.com
 
Tim Wescott <tim@seemywebsite.com> wrote:

On Tue, 20 Sep 2011 10:29:05 +0100, Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality
mic, a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It
proved useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

What _are_ the specs for a typical PC microphone input port? And are
there even specs, or does the circuit just happen to be what the
manufacturer felt like using at the time?

I gather that it's designed for electret microphones, then -- that makes
lots of sense. In theory that means that you could make a preamp that
would be powered by the PC, but that's only "simplest" if you have a well-
stocked junkbox, some knowledge, and some time.
Click to expand...
Thanks Tim. I'm thinking about experimenting with that F-99B (seems a
shame to waste a fairly expensive mic) but it means cleaning up my shed
and workbench first - something I've been putting off for a couple of
years!

I have the first two of those requirements, but time is in short supply.

The circuits in the article referenced by bw up-thread are one starting
point, if I do make the initial effort.
http://www.hobby-hour.com/electronics/computer_microphone.php

I could even avoid the spring clean by doing some bread-boarding here at
my PC. ;-)

--
Terry, East Grinstead, UK
 
Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

I once had a mic like that so I slapped together a bog-basic common
Click to expand...
emitter amplifier as a preamp.
http://www.electronics-tutorials.ws/amplifier/amp_2.html
(page 1 is all full of formulas and stuff - yech!)

Of course, for stereo you'd have to build two of them. ;-)

Have Fun!
Rich
 
On 2011-09-20, Terry Pinnell <terrypingm@DELETEgmail.com> wrote:
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.
My multimeter shows its left and right connections as about 170 ohms.
Click to expand...
You have here a low impedance, dynamic mic, whose output is likely very
low. The mic socket expects a lot higher voltage signal, from a cheap,
high impedance microphone. The gain just isn't there.

What's the simplest way of getting it to work on my PC please?
Click to expand...
Get a (or, seeing what newsgroup this is, build yourself a) microphone
preamplifier. Because the impedance of the mic is low, you can get away
with a low input impedance, like 1000 ohms.

You can also boost the level passively with a transformer. A transformer
will also make the impedance of the mic input look lower to the mic. But
that's okay because the mic has low impedance, and is designed for a
low-ish impedance input.

This mic does not have balanced outputs. It is single-ended, and so it
will pick up noise. This limits the cable length you can use, even
though it is low impedance.
 
On 2011-09-21, Rich Grise <richg@example.net.invalid> wrote:
Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

I once had a mic like that so I slapped together a bog-basic common
emitter amplifier as a preamp.
Click to expand...
For this you can do common base, too!
 
Kaz Kylheku <kaz@kylheku.com> wrote:

On 2011-09-20, Terry Pinnell <terrypingm@DELETEgmail.com> wrote:
In my shed I just came across a very old but apparently high quality mic,
a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It proved
useless when I tried it on my PC, in the usual mic socket.
My multimeter shows its left and right connections as about 170 ohms.

You have here a low impedance, dynamic mic, whose output is likely very
low. The mic socket expects a lot higher voltage signal, from a cheap,
high impedance microphone. The gain just isn't there.

What's the simplest way of getting it to work on my PC please?

Get a (or, seeing what newsgroup this is, build yourself a) microphone
preamplifier. Because the impedance of the mic is low, you can get away
with a low input impedance, like 1000 ohms.

You can also boost the level passively with a transformer. A transformer
will also make the impedance of the mic input look lower to the mic. But
that's okay because the mic has low impedance, and is designed for a
low-ish impedance input.

This mic does not have balanced outputs. It is single-ended, and so it
will pick up noise. This limits the cable length you can use, even
though it is low impedance.
Click to expand...
Rich, Kaz: thanks both.

--
Terry, East Grinstead, UK
 
On Wed, 21 Sep 2011 20:51:13 +0100, Terry Pinnell
<terrypingm@DELETEgmail.com> wrote:

Tim Wescott <tim@seemywebsite.com> wrote:

On Tue, 20 Sep 2011 10:29:05 +0100, Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality
mic, a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It
proved useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

What _are_ the specs for a typical PC microphone input port? And are
there even specs, or does the circuit just happen to be what the
manufacturer felt like using at the time?

I gather that it's designed for electret microphones, then -- that makes
lots of sense. In theory that means that you could make a preamp that
would be powered by the PC, but that's only "simplest" if you have a well-
stocked junkbox, some knowledge, and some time.

Thanks Tim. I'm thinking about experimenting with that F-99B (seems a
shame to waste a fairly expensive mic) but it means cleaning up my shed
and workbench first - something I've been putting off for a couple of
years!

I have the first two of those requirements, but time is in short supply.

The circuits in the article referenced by bw up-thread are one starting
point, if I do make the initial effort.
http://www.hobby-hour.com/electronics/computer_microphone.php

I could even avoid the spring clean by doing some bread-boarding here at
my PC. ;-)
Click to expand...
If you are going to build a preamp anyway, you may want to
connect it to Line In instead of Mic In. Although Mic In is
about 10 times more sensitive (say, 100 mV vs 1V
full-scale), it may be more than 10 times noisier. It also
has (in the sound cards I've tested) a reduced frequency
response of about 9 kHz or so, instead of the full 20 kHz.
(That's not a problem for the originally-intended use with
voice, probably even a good thing.)

I've also seen some sound chipsets that have strange
behavior on Mic In, which might be related to the reduced
frequency range. Looks like it is sampling at a reduced
rate (maybe 18 kHz instead of 48 kHz) and then using sample
rate conversion to get back to 48 kHz equivalent. But there
seems to be minimal anti-aliasing on the original
conversion, so high frequencies (above 9 kHz) wrap back down
with hardly any attenuation. This would be a Very Bad Thing
for music recording.

Mic In is always mono-only, with the Left (white) line
carrying the signal. The Right (red) line is only used for
phantom power for the electret's built-in FET preamp, which
I seem to recall is typically 5V through a 4.7K resistor (or
something like that). But I think some (most?) setups may
apply that directly to the Left. That bias doesn't cause a
problem since the sound card input is AC coupled.

Best regards,


Bob Masta

DAQARTA v6.02
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, FREE Signal Generator
Pitch Track, Pitch-to-MIDI
Science with your sound card!
 
Kaz Kylheku wrote:
On 2011-09-21, Rich Grise <richg@example.net.invalid> wrote:
Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality
mic, a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It
proved useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

I once had a mic like that so I slapped together a bog-basic common
emitter amplifier as a preamp.

For this you can do common base, too!
Click to expand...
Yes, this is also true - at the time, I was too lazy to figure out how
to bias a common base circuit properly. :)

Thanks!
Rich
 
N0Spam@daqarta.com (Bob Masta) wrote:

On Wed, 21 Sep 2011 20:51:13 +0100, Terry Pinnell
terrypingm@DELETEgmail.com> wrote:

Tim Wescott <tim@seemywebsite.com> wrote:

On Tue, 20 Sep 2011 10:29:05 +0100, Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality
mic, a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It
proved useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

What _are_ the specs for a typical PC microphone input port? And are
there even specs, or does the circuit just happen to be what the
manufacturer felt like using at the time?

I gather that it's designed for electret microphones, then -- that makes
lots of sense. In theory that means that you could make a preamp that
would be powered by the PC, but that's only "simplest" if you have a well-
stocked junkbox, some knowledge, and some time.

Thanks Tim. I'm thinking about experimenting with that F-99B (seems a
shame to waste a fairly expensive mic) but it means cleaning up my shed
and workbench first - something I've been putting off for a couple of
years!

I have the first two of those requirements, but time is in short supply.

The circuits in the article referenced by bw up-thread are one starting
point, if I do make the initial effort.
http://www.hobby-hour.com/electronics/computer_microphone.php

I could even avoid the spring clean by doing some bread-boarding here at
my PC. ;-)

If you are going to build a preamp anyway, you may want to
connect it to Line In instead of Mic In. Although Mic In is
about 10 times more sensitive (say, 100 mV vs 1V
full-scale), it may be more than 10 times noisier. It also
has (in the sound cards I've tested) a reduced frequency
response of about 9 kHz or so, instead of the full 20 kHz.
(That's not a problem for the originally-intended use with
voice, probably even a good thing.)

I've also seen some sound chipsets that have strange
behavior on Mic In, which might be related to the reduced
frequency range. Looks like it is sampling at a reduced
rate (maybe 18 kHz instead of 48 kHz) and then using sample
rate conversion to get back to 48 kHz equivalent. But there
seems to be minimal anti-aliasing on the original
conversion, so high frequencies (above 9 kHz) wrap back down
with hardly any attenuation. This would be a Very Bad Thing
for music recording.

Mic In is always mono-only, with the Left (white) line
carrying the signal. The Right (red) line is only used for
phantom power for the electret's built-in FET preamp, which
I seem to recall is typically 5V through a 4.7K resistor (or
something like that). But I think some (most?) setups may
apply that directly to the Left. That bias doesn't cause a
problem since the sound card input is AC coupled.

Best regards,


Bob Masta
Click to expand...
Thanks Bob. That seems to square with the circuits above, yes?

--
Terry, East Grinstead, UK
 
On Fri, 23 Sep 2011 07:27:49 +0100, Terry Pinnell
<terrypingm@DELETEgmail.com> wrote:

N0Spam@daqarta.com (Bob Masta) wrote:

On Wed, 21 Sep 2011 20:51:13 +0100, Terry Pinnell
terrypingm@DELETEgmail.com> wrote:

Tim Wescott <tim@seemywebsite.com> wrote:

On Tue, 20 Sep 2011 10:29:05 +0100, Terry Pinnell wrote:

In my shed I just came across a very old but apparently high quality
mic, a Sony 'F-99B', 'One point stereo dynamic microphone IMP.LOW' It
proved useless when I tried it on my PC, in the usual mic socket.

My multimeter shows its left and right connections as about 170 ohms.

What's the simplest way of getting it to work on my PC please?

What _are_ the specs for a typical PC microphone input port? And are
there even specs, or does the circuit just happen to be what the
manufacturer felt like using at the time?

I gather that it's designed for electret microphones, then -- that makes
lots of sense. In theory that means that you could make a preamp that
would be powered by the PC, but that's only "simplest" if you have a well-
stocked junkbox, some knowledge, and some time.

Thanks Tim. I'm thinking about experimenting with that F-99B (seems a
shame to waste a fairly expensive mic) but it means cleaning up my shed
and workbench first - something I've been putting off for a couple of
years!

I have the first two of those requirements, but time is in short supply.

The circuits in the article referenced by bw up-thread are one starting
point, if I do make the initial effort.
http://www.hobby-hour.com/electronics/computer_microphone.php

I could even avoid the spring clean by doing some bread-boarding here at
my PC. ;-)

If you are going to build a preamp anyway, you may want to
connect it to Line In instead of Mic In. Although Mic In is
about 10 times more sensitive (say, 100 mV vs 1V
full-scale), it may be more than 10 times noisier. It also
has (in the sound cards I've tested) a reduced frequency
response of about 9 kHz or so, instead of the full 20 kHz.
(That's not a problem for the originally-intended use with
voice, probably even a good thing.)

I've also seen some sound chipsets that have strange
behavior on Mic In, which might be related to the reduced
frequency range. Looks like it is sampling at a reduced
rate (maybe 18 kHz instead of 48 kHz) and then using sample
rate conversion to get back to 48 kHz equivalent. But there
seems to be minimal anti-aliasing on the original
conversion, so high frequencies (above 9 kHz) wrap back down
with hardly any attenuation. This would be a Very Bad Thing
for music recording.

Mic In is always mono-only, with the Left (white) line
carrying the signal. The Right (red) line is only used for
phantom power for the electret's built-in FET preamp, which
I seem to recall is typically 5V through a 4.7K resistor (or
something like that). But I think some (most?) setups may
apply that directly to the Left. That bias doesn't cause a
problem since the sound card input is AC coupled.

Best regards,


Bob Masta

Thanks Bob. That seems to square with the circuits above, yes?
Click to expand...
Yes, the:
http://www.hobby-hour.com/electronics/computer_microphone.php
reference squares with my experience regarding connections.

Best regards,



Bob Masta

DAQARTA v6.02
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, FREE Signal Generator
Pitch Track, Pitch-to-MIDI
Science with your sound card!
 
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