1232-A
The General Radio 1232-A Tuned Amplifier and Null Detector was introduced in Catalog Q (1961) and remained available through Catalog 1978.
The 1232-A is a solid-state, battery-operated tuned amplifier and null detector. Its tuned frequency range covers 20 to 20 kHz in 5 bands, plus a flat response setting.
As a null detector, the 1232-A is part of the GR 1660-A Inductance and 1620-A Capacitance Measurement Systems. Battery operation is provided by nine M72 cells (now obsolete). The instrument shown in the photos below has been converted to a rechargeable battery pack. (Instructions for this conversion are covered in a document below.)
Specifications
- Frequency Response:
- Tunable Filters: 20 Hz to 20 kHz in 3 ranges; 5% bandwidth; 2nd harmonic at least 34 dB down from peak, 3rd at least 40 dB down
- 50 kHz and 100 kHz Filters: 2nd harmonic 44 and 53 dB down, respectively
- Flat Response: ±3 dB from 20 Hz to 100 kHz
- Input Impedance: Approximately 50 kΩ at maximum gain, varies inversely with gain to 1 MΩ at minimum gain
- Gain: 120 dB on the tunable ranges; 100 dB, flat range; 106 dB at 50 kHz; 100 dB at l00 kHz position
