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A36A

Sensibly equivalent to:
TH4
See also:
Some Important British Valves
    
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The A36A from Ever Ready was made under contract by Mullard and is a renamed TH4 triode hexode mixer dating to 1936.
In the 1930s the UK still had a mix of AC and DC mains supplies and so called 'universal' sets were made with series heater chains and the HT taken from the mains via a rectifier - redundant on the DC mains of course. Mullard made the TH21C which was the TH4 with a 200 mA heater for these sets. If the mains plug was wired incorrectly the chassis would be live and thus potentially lethal.
The B7 base cap.
Thanks to Mark Mallison for sending the images.
The classic envelope is 45 mm in diameter, and excluding the B7 base pins is 115 mm tall.
References: Data-sheet & 1043. Type A36A was first introduced in 1936. See also 1936 adverts.

 

Pin Connections
B7
1
2
3
4
5
6
7
tc
a(t)
g1(t),g3
g2,g4
h
h
m,k
a
g1

 

Absolute Maximum Operating Conditions
Hexode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
4.0
1.5
250
70
-2
4.0
6.0
1.5M
1.0

 

Absolute Maximum Operating Conditions
Triode
Va
mAa
gm
150
6.0
1.2
Thanks to Andy Cowley for supplying the above PDF datasheet.
Updated August 23, 2022.
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