CBL31 @ The Valve Museum

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CBL31

Sensibly equivalent^¶ to:

CV1463

Extras ▼

Mullard The Signals Museum - RAF Henlow. Other CBL31 exhibits

The Mullard CBL31 dates from 1938 and was designed for low cost superhet broadcast receivers mainly for local station use. The diodes function as AGC rectifier and signal detector (demodulator of AM signals) whilst the high gain pentode amplifies the detected signal and drives the loud speaker.

See also CBL1, CL4 and CL33.

The top mica holds the electrodes including the reduced diameter cathode tube. All three wire grids are clear as is the mesh anode.

The double diodes are a pair of rods contained in the screening box shown. The tape is the connection to the cathode.

The classic envelope is 44 mm in diameter, and excluding the IO base pins is 120 mm tall.

References: Data-sheet & ¹⁰⁴³. Type CBL31 was first introduced in 1938. See also 1938 adverts.

Pin Connections

IO	1	2	3	4	5	6	7	8	tc
	m	h	a	a(d2)	a(d1)	g2	h	k	g1

Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	rk	rl	Pout	D
	44.0	0.2	200	200	-8.5	45.0	6.0	35,000	8.0	167	4,500	4.0W	10%

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated September 12, 2024.

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