The 6AJ7 metal pentode was made in Canada for Marconi, and designed for high gain amplification. Although we do not have details it was probably used in WW2 for radar receivers.

Data for type 6AJ7, including pin connections, is identical to that for type 6AC7 but there is presumably some difference sufficient to justify a new type number. 6AC7s were supplied by several US manufacturers but 6AJ7s were (mostly?) made outside the US and are described in some sources as 'Am-Brit' rather than 'USA'. Perhaps type 6AJ7 had a different internal construction to enable it to be supplied by manufacturers not equipped to make (say) the RCA patented type of lead-out seal. If so, perhaps the high-frequency performance of the 6AJ7 is sufficiently inferior to that of the 'real thing' to make it unsatisfactory for some applications, though perfectly good for others.

The thin metal envelope is 24 mm in diameter and, excluding the IO base pins, is 50 mm tall.

 
Pin Connections

IO	1	2	3	4	5	6	7	8
	m	h	g3	g1	k	g2	7	a

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.45	300	150	-2	10	2.5	1M	9

This exhibit was last updated on 04 August 2006