7D3 @ The Valve Museum

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7D3

Sensibly equivalent^¶ to:

40PPA

See also:

Ten Times Tested Valves Advert

Extras ▼

Brimar TNMoC The National Museum of Computing - Valves

The 7D3 is an audio output pentode that was designed for single ended use in universal sets. The heater is designed for series connection across the mains supply, and the anode ratings reflect the low HT available when no mains transformer is available.

The 25A6G is the same valve electrically but with a 300 mA heater and an IO base cap.

The Brimar identification on the base cap.

The classic envelope is 44 mm in diameter, and excluding the B7 base pins is 95 mm tall.

References: Data-sheet & ¹⁰⁴⁰. Type 7D3 was first introduced in 1935. See also 1935 adverts.

Pin Connections

B7	1	2	3	4	5	6	7	8
	m	h	a	g2	g1	nc	h	k

Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	Pout	D
	40	0.2	160	120	-18	36	12	42,000	2.4	2.2	10%

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated January 09, 2022.

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