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UL84

Sensibly equivalent to:
10P18 45B5 N119
See also:
Transformerless Amplifiers - New Valve Assembly Method
    
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The Mullard EL84 is a classic audio pentode valve, immortalised in the 1950s 5-10 design for an audio amplifier. The UL84 was designed with a 100 mA heater, for use in universal voltage environments and thus with limited HT available. Our exhibit carries the Mullard logo but was not of UK manufacture.
On a DC mains supply no transformer to increase the HT voltage is possible so the UL84 is designed to operate at lower anode voltages and increased anode current.
The UL84 can be used for push pull operation but the normal service would have been in single ended applications such as radios and record players.
The PL84 is another variant but with a 300 mA heater. The main application was TV frame output but audio was also possible.
The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins the valve is 68 mm long.
References: Datasheet. Type UL84 was first introduced in 1955.

 

Pin Connections
B9A
1
2
3
4
5
6
7
8
9
ic
g1
k,g3
h
h
ic
a
ic
g2

 

Absolute Maximum Operating Conditions
Beam Tetrode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
Pdiss
Pout
D
45
0.1
170
170
-12.5
70
5
230k
10
12.0W
5.2
10%
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated April 23, 2014.
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