Help me identify an old German tube mic

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

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
--
--
John Noll
2 answers Last reply
More about help identify german tube
  1. 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/?SQ=bbfcd7867d8bad9501816c50f430e6eb

    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
    >--
  2. 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."
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