Telefunken C14 and G7..

[tomom]

Can Telefunken C14 be used with G7 tube amplifier?  Would anyone know specifications of C14 and pinout of three pin connector? Thanks Tomo...

 

[ln76d]

Yes and no

You can connect it to the G7 head-amplifier,  But it's probably not worth.
These type of condenser microphones were connected direct to the equipment.
There's no specification for this model. Polarisation probably is 100V as in similar mikes.
It should have pretty high output and high impedance. Polarisation voltage + transformer could be enough.
Open it, put some pictures here.

 

[tomom]

here is the picture, not the best quality...how will I figure out which of three wires on the three pin connector has to be connected to where..can you sketch connection to 100 volts and transformer?...Thanks Tomo

 

[MS Vienna]

Hi,

I had this mic somewhere in my memory, so I researched it in my documents. Sure enough it was made in Vienna by AKG in the beginning 1960´s.
It was meant to be connected directly to Telefunken "Magnetophon" tape machines.
Specifications:
Frequency response: 30-18000Hz
Sensitivity: 30mV/Pa @ 160V polarisation (supplied by mic input of tape machine - input impedance 2MOhm)
Capsule capacitance: 1500pF
Diaphragm: 9µm Mylar with 25µm distance from backplate

It´s generally an omni mic but there were cardioid versions built upon request too.

There have been prototypes of a "C22" which was a stereo mic consisting of two C14. It never made it into serial production though.

I don´t have pinout but just measure it since you have it open already.

 

[ln76d]

Sh.t!

I just realized, that it can be really great diaphragm donor for typical LDC capsule

 

[tomom]

Thank you in76  and MS Viena for help and very useful information...I guess that best would be to find diagram of that Telefunken Magnetophon... MS Viena would you know which model Magnetophon was C14 used with...

 

[MS Vienna]

Hi,

I don´t know about Magnetophon model, sorry.

As for diaphragm donor: the C14 diaphragm is only approx. 45 mm wide. That´s too narrow already to be used in the tensioning device for large diaphragm capsules.  60mm width minimum is needed for proper results. You can leave those C14s intact 

 

[ln76d]

here is the picture, not the best quality...how will I figure out which of three wires on the three pin connector has to be connected to where..can you sketch connection to 100 volts and transformer?...Thanks Tomo

Here's a basic idea of connection. I don't know if this will work
You can try

Open connector, check which one is ground.
Take a multimeter and check is there continuity between ground pin and any other pin.
At the front of the diaphragm you have also connectors (it looks like) - check continuity between them and  output pins.

 

[ln76d]

As for diaphragm donor: the C14 diaphragm is only approx. 45 mm wide. That´s too narrow already to be used in the tensioning device for large diaphragm capsules.  60mm width minimum is needed for proper results. You can leave those C14s intact.

If i will find some i will try anyway
My idea is to put the glue on the plastic ring of the capsule and put it on C14 (or any other) diaphragm already tensioned.
After glue dry  - cut it.
Worth to try

 

[MS Vienna]

I get your idea - basically it´s very good.

However the C14 is a quite special design. Obviously a diaphragm of that size with a distance of only 25µm to the backplate could normally never work with a polarisation voltage of 160V - not even with the usual 62V. It would get sucked to the backplate immediately. The C14 capsule doesn´t rely on diaphragm tension! Dr. Görike (co-founder of AKG and one of the company´s brightest minds) had the brilliant idea to make this capsule work reliably: there´s a nylon filament of 25µm thickness wrapped around the (aluminium sheet)backplate with 6mm distance between each wrap (not really visible in Tomo´s picture). This supports the diaphragm sufficiantly and defines a consistant backplate distance  under polarization. The goal was to offer a c-mic for amateur use that´s cheap to manufacture but reliable enough in function. 

Most likely you won´t end up with the right tuning frequency in your selfmade diaphragm. In any case the rear side will be far from being perfectly plane and with impressions of the nylon filament in the glue.

BTW - if you need material for diaphragms aluminium sputtered polyester film is readily available in various gauges from 2µm upwards AFAIK.