AMPLIFIER No. 55A
3-stage amplifier with optional selective feed back circuit adjusted to zero at 1000 c/s.

Used with a Receivers, Headgear No. 15.

Use:-
1. with Oscillator No. 24A and Probe No. 5 for identification of cable pairs.
2. with Oscillator No. 23A and Probe No. 3 for identifying cables.
3. with Oscillator No. 23A and Search Coil No. 1 for location of cables.

Includes:-
1 x Case No. 57A.
1 x Cord, Instrument No. 4/67L, 7".
1 x Jack No. 81B.
1 x Transformer No. 190A.
3 x Valves, Electronic CV 784.
3 x Valve-holders No. 32A.

Uses a Battery, Dry No. 18 and a Battery, Dry No. 20.

Drawing - 63999.

Circuit Diagram - SA9091.

Specification - D1820.
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Last revised: December 04, 2025
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