I picked up this microphone on Ebay recently...
Photo
Another photo
inside photo
It's a bit of an oddball mic. At first I thought it was some kind of prototype by Reissmann, Teladi or some other mic manufacturer, but the more I look at it, the more I think it's an old DIY microphone, including the capsule. It may well be inspired by some of the old tube microphone articles by Williamson, Debenham and o on.
The metalwork is nicely done - by someone with some skill on the lathe, and the wiring is done by someone who undertood working with high impedance circuits. However, the designer made it impossible to change the tubes without dismantling the entire mic. :
I've traced out the circuit, which is based around an EF40 and ECC81. The original power supply is not present.
The capsule itself is interesting as the tension, or gap to the backplate, may be adjusted using springs and screws. It arrived with no diaphragm, but I'll see if I can get it working with some aluminium coated mylar. I'll take some better photos of that later.
S
Photo
Another photo
inside photo
It's a bit of an oddball mic. At first I thought it was some kind of prototype by Reissmann, Teladi or some other mic manufacturer, but the more I look at it, the more I think it's an old DIY microphone, including the capsule. It may well be inspired by some of the old tube microphone articles by Williamson, Debenham and o on.
The metalwork is nicely done - by someone with some skill on the lathe, and the wiring is done by someone who undertood working with high impedance circuits. However, the designer made it impossible to change the tubes without dismantling the entire mic. :
I've traced out the circuit, which is based around an EF40 and ECC81. The original power supply is not present.
The capsule itself is interesting as the tension, or gap to the backplate, may be adjusted using springs and screws. It arrived with no diaphragm, but I'll see if I can get it working with some aluminium coated mylar. I'll take some better photos of that later.
S