The 6AQ5 is a small audio output beam tetrode valve capable of 4.5 Watts in a single ended configuration.

See also EL90 by Brimar but named with the Mullard naming convention.

The thin glass tube envelope is 17 mm in diameter and excluding the B7G base pins, is 58 mm long.

References: Datasheet & ¹⁰⁴⁰. Type 6AQ5 was first introduced^¶ in 1950.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	g1	k,bp	h	h	a	g2	g1

 
Absolute Maximum Operating Conditions^¶

Beam Tetrode	Vh	Ah	Va	Vs	Vg	mAa	ra	rk	rl	gm	Pout
	6.3	0.45	250	250	-12.5	45	52,000	240	5,000	4.1	4.5W

Thanks to Frank Philipse for supplying the above PDF datasheet

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