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ID = 49837
Great Britain (UK)
Brand: Hivac Ltd.; Harrow-on-the-Hill
Tube type:  HEPTODE 
Identical to A15_Hivac

Base Octal (Int.Octal, IO) K8A, USA 1935 Top contact with a cap.
Filament Vf 15 Volts / If 0.3 Ampere / Indirect
Description The "All-purpose" tube was announced by J H Owen Harries of Harries Thermionics Ltd in November 1936. It was designed by Harries using the crtical-distance anode spacing principal.
Manufactured by Hivac from 1937 it was promoted for use in RF, mixer, IF, detector AF and output stages. It was referred to as the "Hivac-Harries All-Stage". The A15 designation was added later.

Va<400; Vg2/Vg5 <300. Capable of 5.3W output class A. (Valve Data 1937)
Va<300; Vg2/Vg5 <250. (Harries announcement Nov 1936)

It was never successful as there was no great benefit to be achieved by the use of a single type which of necessitity degraded the performance relative to purpose-designed ones or required additional tubes to achieve the same performance. In addition, as Hivac were outside the BVA, they tended to receive less publicity and the set manufacturers were reluctant to offend the main BVA tube manufacturers. (RFJ)

CONNECTIONS:- Top cap grid, pins 1-8 are H C A g5 g4 g3 g2 H 

Information source - - Manufacturers Literature   Practical and Amateur Wireless Jan 1939
Wireless World (The), London (WW, 79)   Article p 559 November 20th 1936.
  A15_Hivac: Mfg. data sheet
Jay Kinnard
A15_Hivac: own collection
John Koster

A15_Hivac: Mfg. drawing
Jay Kinnard


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