Rough guess at these impedances...

[Paul Burridge]

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?
--

"What is now proved was once only imagin'd." - William Blake, 1793.

 

[John Larkin]

On Tue, 11 May 2004 19:49:18 +0100, Paul Burridge
<pb@notthisbit.osiris1.co.uk> wrote:

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?

1 / (2*pi*f*c)

John

 

On Tue, 11 May 2004 19:49:18 +0100, Paul Burridge <pb@notthisbit.osiris1.co.uk>
wrote:

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?

I'll assume you mean an electret type microphone? I don't know of anyone who
makes a condensor microphone anymore. Those things take 500 volts of extremely
well filtered DC and the impedance is purely the capacitance of the plates.
Crooners hated them in the old days because if the stage electrician screwed up,
they could get the entire 500 volts on their lips as they 'kissed' the
microphone.

Figure 2.2k to 4.7k for electrets with three wires. On two wire types, set the
impedance with the bias resistor size. You can get more sensitivity by
increasing the drain resistor, but you sacrifice high frequency response and
dynamic range if you go too far with it.

 

[John Fields]

On Tue, 11 May 2004 19:49:18 +0100, Paul Burridge
<pb@notthisbit.osiris1.co.uk> wrote:

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?

---
Electret or straight RC?

--
John Fields

 

[Paul Burridge]

On Tue, 11 May 2004 14:28:31 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Tue, 11 May 2004 19:49:18 +0100, Paul Burridge
pb@notthisbit.osiris1.co.uk> wrote:

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?

---
Electret or straight RC?

Electret. Someone told me they're also now available with a SMD
transistor amp built-on.
Just a ball-park figure would suffice.

--

"What is now proved was once only imagin'd." - William Blake, 1793.

 

[John Fields]

On Tue, 11 May 2004 23:40:32 +0100, Paul Burridge
<pb@notthisbit.osiris1.co.uk> wrote:

On Tue, 11 May 2004 14:28:31 -0500, John Fields
jfields@austininstruments.com> wrote:

On Tue, 11 May 2004 19:49:18 +0100, Paul Burridge
pb@notthisbit.osiris1.co.uk> wrote:

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?

---
Electret or straight RC?

Electret. Someone told me they're also now available with a SMD
transistor amp built-on.
Just a ball-park figure would suffice.

---
Roughly the value of the load resistor, but take a look at this:

http://www.hut.fi/Misc/Electronics/circuits/microphone_powering.html

--
John Fields

 

[Tom Bruhns]

Paul Burridge <pb@notthisbit.osiris1.co.uk> wrote in message news:<jq72a0dv7bqm26e7f72bn8alp244odktt1@4ax.com>...

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?

Generally within an order of magnitude of 1e12/s. Or did you mean an
electret with built-in amplifier? Two wire, or three? ... Do a
Google search for "electret microphone impedance."

Cheers,
Tom

 

[Walter Harley]

"Paul Burridge" <pb@notthisbit.osiris1.co.uk> wrote in message
news:jq72a0dv7bqm26e7f72bn8alp244odktt1@4ax.com...

Anyone know or care to guess what the typical impedance of a condenser
mic is?

Easiest way to answer that would be to go look at some manufacturer specs.

I'll ignore the distinction between electret and condensor and going with
common usage, and assume, without justification, that you are talking about
the output impedance at the XLR connector of a balanced mic. In other
words: you want to know what the output impedance of, say, a Shure SM87 or
an Audio-Technica AT4033 is. Answer, based on a quick nonsystematic sample:
about 100 ohms on average.

But I'm not sure why you care. Like the rest of pro audio, they're not
intended to be loaded by an equal impedance. Generally they want to see
around 1k.

As others have noted, this has nothing whatsoever to do with the impedance
of the actual mic element, which is basically a capacitor with a fixed
charge on it.

 

[martin griffith]

On Tue, 11 May 2004 19:49:18 +0100, Paul Burridge
<pb@notthisbit.osiris1.co.uk> wrote:

HI

Anyone know or care to guess what the typical impedance of a condenser
mic is?
have a llok at

http://www.panasonic.com/industrial/components/pdf/em16_microphone%20schematic_dne.pdf




martin

Three things are certain:
Death, taxes and lost data.
Guess which has occurred.

 

[Paul Burridge]

On 12 May 2004 06:25:09 GMT, "Walter Harley"
<walterh@cafewalterNOSPAM.com> wrote:

"Paul Burridge" <pb@notthisbit.osiris1.co.uk> wrote in message
news:jq72a0dv7bqm26e7f72bn8alp244odktt1@4ax.com...
Anyone know or care to guess what the typical impedance of a condenser
mic is?

Easiest way to answer that would be to go look at some manufacturer specs.

I'll ignore the distinction between electret and condensor and going with
common usage, and assume, without justification, that you are talking about
the output impedance at the XLR connector of a balanced mic. In other
words: you want to know what the output impedance of, say, a Shure SM87 or
an Audio-Technica AT4033 is. Answer, based on a quick nonsystematic sample:
about 100 ohms on average.

But I'm not sure why you care. Like the rest of pro audio, they're not
intended to be loaded by an equal impedance. Generally they want to see
around 1k.

As others have noted, this has nothing whatsoever to do with the impedance
of the actual mic element, which is basically a capacitor with a fixed
charge on it.

Thanks, but I appreciate that, Walter. This is simply for simulation
purposes. I just need to have a value to bung in the signal source box
or the gain of this amp stage will not be meaningfully calculable.

--

"What is now proved was once only imagin'd." - William Blake, 1793.