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EBL21

Sensibly equivalent to:
DN143
    
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The EBL21 is one of very few double diode audio output pentode valves that were designed. This exhibit was made by Philips in Holland under the Valvo brand during the Nazi occupation. The BAL Luftwaffe acceptance stamp can be seen.
The valve has a common cathode and the diodes are for signal rectification for detector or AGC service. It would have needed considerable drive at the intermediate frequency and the output pentode is of high gain to allow the use a a single stage from detector to output transformer.
The Valvo brand on the dome
Thanks to Martin Tomiak DL7ARY for the images and details of the 1941 introduction.
The wide glass tube envelope is 28 mm in diameter and, excluding the B8B base pins, is 75 mm tall.
References: Data-sheet, 1040 & 3002. Type EBL21 was first introduced in 1941.

 

Pin Connections
B8B
1
2
3
4
5
6
7
8
h
a
g1
g2
a(d2)
a(d1)
k
h

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
Pout
D
6.3
0.8
250
275
-6.2
44
5.8
50K
9.5
5.5
10%
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated March 08, 2021.
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