Help me identify an old German tube mic

Archived from groups: rec.audio.pro (More info?)

You should try asking Klaus Heine on the pro sound forum, he is a
German mic expert.

http://recforums.prosoundweb.com/index.php/f/33/1899/?S...

Looking at the photo of the mic, it seems a poor design to have the
tube right next to the capsule. The heat from the tube might cause
some problems.

Al

On Fri, 20 Aug 2004 16:36:49 GMT, John Noll <jn145@verizon.net> wrote:

>I recently obtained an interesting vintage tube mic that
>I believe is called a Thiel M4. See photo links below.
>
>http://retromedia.net/m4mic.JPG
>
>http://retromedia.net/m4_a.jpg
>
>http://retromedia.net/m4_b.jpg
>
>It supposedly has an M7 capsule and uses an ECC83 tube.
>It's very unusual in that the 220v power supply is
>inside the mic body. It has 200 ohm output, but there
>doesn't appear to be an output transformer.
>
>The literature I have has the names:
>Bedienungsanleitung, Elektro-Medizin, Vakuum-Technik
>
>Does anyone know anything about this mic or point me to
>someone who might? Thanks
>--

Archived from groups: rec.audio.pro (More info?)

playon <playonATcomcast.net> wrote:
>
>Looking at the photo of the mic, it seems a poor design to have the
>tube right next to the capsule. The heat from the tube might cause
>some problems.

If it isn't a PVC diaphragm, this is a good thing because it bakes moisture
out of the capsule and keeps it nice and warm.

When B&K went from tube to solid state electronics, their earlier solid
state mikes had resistive heaters to keep the capsules warm and reduce
problems in humid environments.

If it's a PVC diaphragm, it bakes the plasticizer out of the diaphragm
as well, which is very bad.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."