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 1240-A Bridge Oscillator-Detector, the 1660-A Inductance Measurement System, and the 1620-A Capacitance Measurement System. 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

Links

• Experimenter July 1961 describing Type 1232-A
• Experimenter February 1967 describing 1232-P2 Preamplifier
• GR 1232-A Battery Conversion

Photos

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  Late model, white front-panel 1232-A as part of a 1240-A