The 30L15 is a low impedance high gain double triode. The low voltage high current suggests a low noise design, used in the front end stages in a television tuner.

The other 30L15 in the museum has a different construction. This one has a perforated outer screen as well as an inter-section screening plate.

The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 47 mm tall.

References: Datasheet & ¹⁰⁴⁰. Type 30L15 was first introduced^¶ in 1960.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	a(2)	g1(2)	k(2)	h	h	a(1)	g1(1)	k(1)	s

 
Absolute Maximum Operating Conditions^¶

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	7	0.3	90	-1.2	15	3100	9

Thanks to Frank Philipse for supplying the above PDF datasheet

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