▼ Menu

EF37A

Sensibly equivalent to:
5A/157D CV358 CV5080 OM5B
See also:
Evolution from EF36 & EF37 to EF37A - The Williamson Amplifier
    
Extras ▼

 

Mullard designate the EF37A as a high gain, high impenance, pentode for use in AF pre-amplifier stages. The electrode system is of anti-microphonic construction, and the specially designed heater reduces hum to negligible proportions.
High quality amplifiers have used the EF37A for many decades. The ME1400 electrometer pentode is also rated for high quality audio use and is a direct replacement for the EF37A upon which it was based. The EF86 was its successor.
The data sheets also give parameters for use as a triode.
See also 6J7 almost the same valve in operation.
The reverse is plain metallic paint. This exhibit was first unwrapped for this entry and all the metal work is bright with no sign of corrosion.
The classic envelope is 29 mm in diameter and, excluding the IO base pins, is 85 mm tall.
References: 1004 & 1040 Type EF37A was first introduced in 1942.

 

Pin Connections
IO
1
2
3
4
5
6
7
8
m
h
a
g2
g3
nc
h
k

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.2
250
100
-2
3
0.8
2.5M
1.8
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated October 28, 2015.
Return to Main Index