Capacitor/Condenser Microphones

[Jim Thompson]

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Don Pearce]

On Sat, 06 Nov 2004 12:50:27 -0700, Jim Thompson
<thegreatone@example.com> wrote:

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson

Sennheiser make RF-based microphones. The MKH range is what you want.

d
Pearce Consulting
http://www.pearce.uk.com

 

[Richard Crowley]

"Jim Thompson" wrote ...

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Yes, I seem to recall that some early designs used RF, but likely
nothing in the last 50 years.

Does anyone have some links?

There are some microphone historians that may know over
on news:rec.audio.pro

I once thought about making a "direct digital" mic by using
a condenser mic capsule in an RF oscillator circuit and a
high-speed freq counter to generate the digital samples.

 

[Richard Crowley]

"Jim Thompson" wrote ...

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

http://www.sennheiser.se/filer/sennheiser/RF_Microphones.pdf

I got lots of hits on Google with: rf condenser -interference -wireless
(because many sites mention "RF interference" and/or wireless mics)

(If my previous posting didn't get cancelled properly, ignore it!)

 

[Joerg]

Hi Richard,

(If my previous posting didn't get cancelled properly, ignore it!)


How can you cancel a post to an unmoderated newsgroup? Just curious.

Regards, Joerg

http://www.analogconsultants.com

 

[Richard Crowley]

"Rich The Philosophizer" wrote ...

Richard Crowley wrote:
cancelling a message is a rather unreliable exercise.

OK, lessee-

I saw it at 2:07pm PST. My newsreader says that you
posted your message at 2:02 But the timestamps are
not particularly reliable, either IME.

 

[Guy Macon]

Joerg wrote:

How can you cancel a post to an unmoderated newsgroup? Just curious.

Send a post using this syntax:

(start)

Newsgroups: sci.electronics.design,sci.electronics.misc
Subject: cmsg cancel <Xqbjd.5537$zx1.2586@newssvr13.news.prodigy.com>
Message-ID: <cancel.Xqbjd.5537$zx1.2586@newssvr13.news.prodigy.com>
Control: cancel <Xqbjd.5537$zx1.2586@newssvr13.news.prodigy.com>
References: <Xqbjd.5537$zx1.2586@newssvr13.news.prodigy.com>
Supersedes: <Xqbjd.5537$zx1.2586@newssvr13.news.prodigy.com>
X-Cancelled-By: notthisjoergsch@removethispacbell.net
Approved: notthisjoergsch@removethispacbell.net
Sender: notthisjoergsch@removethispacbell.net
From: notthisjoergsch@removethispacbell.net
X-No-Archive: Yes

cancel <Xqbjd.5537$zx1.2586@newssvr13.news.prodigy.com>

(end)

****************************************************

Here is a template, ready for you to enter your info:

Newsgroups:
Subject: cmsg cancel <>
Message-ID: <cancel.>
Control: cancel <>
References: <>
Supersedes: <>
X-Cancelled-By:
Approved:
Sender:
From:
X-No-Archive: Yes

cancel <>

 

[BFoelsch]

I have used quite a few old condenser mikes, but I think the only OLD ones
that used an RF oscillator/detector/discriminator were the Stevens Tru-Sonic
units, about 1949-1950.
The most popular of the line was the Stevens C-2S, which was used with the
OD-4 oscillator demodulator unit.

Kind of a counter-intuitive setup, the OD-4 contained a crystal oscillator,
and the microphone head contained the capacity element and a small inductor.
The oscillator ran of course at a fixed frequency, but the microphone proper
was part of a discriminator circuit. Microphones were tremendous, sound
wise, but a real pain otherwise. Because everything was tuned, the mike and
the O/D unit needed matching serial numbers, and cable damage was generally
catastrophic, as the cable capacitance was part of the discriminator
circuit.

I don't have a link, but I do have a schematic and specs here.

Other than that, I don't know of any other mikes that used RF. By far the
vast majority just used a DC polarized capacitor element with an amplifier
in the mike head.

"Jim Thompson" <thegreatone@example.com> wrote in message
news:1kaqo05rurt5015riodfvvia57s7tdvpna@4ax.com...

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Tim Wescott]

Jim Thompson wrote:

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson

Whuffo you doing this?

If it's of interest QST ran a couple of articles a while back on home
brewing your own condenser mics, but they use HV DC and FET preamps to
extract the signal. Pretty clever -- the author was claiming high audio
quality from aluminum foil and other household items, but then it always
sounds better when you do it yourself...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Tim Williams]

"Rich The Philosophizer" <null@example.net> wrote in message
newsan.2004.11.06.21.11.39.691170@neodruid.org...

OK, lessee-

Not only that but most servers don't honor the cancellation either,
something known as Dave the Resurrector I recall...

Tim

--
"I've got more trophies than Wayne Gretsky and the Pope combined!"
- Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

 

[Rich The Philosophizer]

On Sat, 06 Nov 2004 14:09:49 -0800, Richard Crowley wrote:

"Rich The Philosophizer" wrote ...
Richard Crowley wrote:
cancelling a message is a rather unreliable exercise.

OK, lessee-

I saw it at 2:07pm PST. My newsreader says that you
posted your message at 2:02 But the timestamps are
not particularly reliable, either IME.

Fascinating!

I clicked cancel about four seconds after I clicked "send"!

Well, maybe ten.

The thread isn't up at google yet, but it's only been a few
minutes.

Cheers!
Rich

 

[James Meyer]

On Sat, 06 Nov 2004 16:44:15 -0700, Jim Thompson <thegreatone@example.com>
wroth:

Think micro-microphones ;-)

...Jim Thompson

You gonna integrate it onto a hunk of silicon? MEMS-like?

Aren't there integrated pressure sensor chips around. All you need to
do is make one with high enough frequency response. Gain shouldn't be a problem
since the amp can go right on the same piece of silicon.

Jim

 

[Watson A.Name - \"Watt Su]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:Xqbjd.5537$zx1.2586@newssvr13.news.prodigy.com...

Hi Richard,

(If my previous posting didn't get cancelled properly, ignore it!)


How can you cancel a post to an unmoderated newsgroup? Just curious.

Regards, Joerg

http://www.analogconsultants.com

Your browser is supposed to know how to do it, but IIRC, you post a
cancel message to the control newsgroup. See one of the many Usenet
FAQs that are out there, and also the relevant RFC(s).

 

[Watson A.Name - \"Watt Su]

"Rich The Philosophizer" <null@example.net> wrote in message
newsan.2004.11.06.21.11.39.691170@neodruid.org...

On Sat, 06 Nov 2004 13:56:20 -0800, Richard Crowley wrote:

"Joerg" wrote ...
How can you cancel a post to an unmoderated newsgroup? Just
curious.

Canceling a message (only your own, of course!) is a
fundamental part of Usenet and the NNTP protocol.

How it is implemented is dependent on which news-reader
application you are using. I use MS Outlook Express and the
function is found in the menu bar under "Message". In the
drop-down menu is a selection for "Cancel Message"

Note, however, that because of the speed of the modern
internet infrastructure, your Usenet message may have
already been forwarded to hundreds (thousands?) of news
servers and may have already be read/downloaded by
thousands of readers before the cancel message can go
out and do its thing. Usenet was a "store-n-forward" or
a kind of "peer-to-peer" sharing protocol long before
Napster, et. al. came along. Because of that, cancelling
a message is a rather unreliable exercise.

OK, lessee-

Well, if you tried to cancel this message, then it didn't work,
obviously...

 

[Watson A.Name - \"Watt Su]

"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com>
wrote in message news:10ori11i6kf0v5b@corp.supernews.com...

"Tim Williams" <tmoranwms@charter.net> wrote in message
news:10oqoih8ube6h70@corp.supernews.com...
"Rich The Philosophizer" <null@example.net> wrote in message
newsan.2004.11.06.21.11.39.691170@neodruid.org...
OK, lessee-

Not only that but most servers don't honor the cancellation either,
something known as Dave the Resurrector I recall...

I believe the D (Dave) version was superseded by the G version a few
years ago. I don't know what version it's on now. Thanks to
Hipcrime.
:-(

But I think the resurrector is for rogue cancellations, not for
cancellations from the originator. So it may not prevent you from
cancelling your own posts. But I think AOL is one of the major usenet
servers that doesn't honor cancels. But that's from what I knew about
it several years ago.

http://www.faqs.org/faqs/usenet/cancel-faq/appendix/

Tim
--

 

[Pooh Bear]

Don Pearce wrote:

On Sat, 06 Nov 2004 12:50:27 -0700, Jim Thompson
thegreatone@example.com> wrote:

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson

Sennheiser make RF-based microphones. The MKH range is what you want.

I thought Schoeps did too.


Graham

 

[Pooh Bear]

Joerg wrote:

Hi Richard,

(If my previous posting didn't get cancelled properly, ignore it!)


How can you cancel a post to an unmoderated newsgroup? Just curious.

In Netscape - which I still prefer to browse ngs. Click on 'cancel
message'


Graham

 

[N. Thornton]

"Tim Williams" <tmoranwms@charter.net> wrote in message news:<10oqoih8ube6h70@corp.supernews.com>...

"Rich The Philosophizer" <null@example.net> wrote in message
newsan.2004.11.06.21.11.39.691170@neodruid.org...
OK, lessee-

Not only that but most servers don't honor the cancellation either,
something known as Dave the Resurrector I recall...

Tim

think cancellation got abused too much.

NT

 

[Tim Shoppa]

Jim Thompson <thegreatone@example.com> wrote in message news:<1kaqo05rurt5015riodfvvia57s7tdvpna@4ax.com>...

Didn't some old capacitor/condenser microphones use RF oscillation?

You know, every time I build a VHF oscillator I end up with so much in
the way of microphonics that I wish someone had hired me to build a
microphone instead

Tim.

 

[Watson A.Name - \"Watt Su]

"Tim Shoppa" <shoppa@trailing-edge.com> wrote in message
news:bec993c8.0411070718.14c76e9f@posting.google.com...

Jim Thompson <thegreatone@example.com> wrote in message
news:<1kaqo05rurt5015riodfvvia57s7tdvpna@4ax.com>...
Didn't some old capacitor/condenser microphones use RF oscillation?

You know, every time I build a VHF oscillator I end up with so much in
the way of microphonics that I wish someone had hired me to build a
microphone instead

Amen! But then I guess it's because I don't use silver plated copper
chassis, with shock mounted caps and feedthrus all over the place.

> Tim.