Lomo 19A9

Produced by Leningrad Optical and Mechanical Association (LOMO), a state-run manufacturer better known for it's optics and photographic equipment, the 19A9, produced from around 1962, was designed for broadcast and studio recording.

Manufacturer Specification:

• Tube cardioid condenser (uses 6J1P / EF95 tube), with large single-sided diaphragm (5 µm gold-sputtered)
• Frequency Response ~40 Hz – 15 kHz
• Output Sensitivity ~0.5 mV/Pa
• Output Impedance ~37 Ω (switchable to ~100 Ω)
• Connector: 4-pin Soviet-style (DIN/Tuchel), paired with external PSU (20B35) housing tube heater and toroidal output transformer

Discussion of further technical details of the LOMO 19A9, PSU design, and schematics can be found here at GroupDIY.

The original manual and circuit diagram are here.