7D5 @ The Valve Museum

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7D5

Sensibly equivalent^¶ to:

CV1425 N30 PP13A PTA

Extras ▼

Brimar G8LSD Valve Collection

The 7D5 is an output pentode designed for audio amplification in radio receivers. The operating values given are for single ended use with an anode load of 7,000 Ohms.

If a pair are used as an audio amplifier in push pull class A, 10.5 Watts are possible with 3% distortion.

The 7D5 has a 13 Volt 0.315 Amp heater and is fitted with a B7 base cap but electrically is identical to the 6F6G that has a 6.3 Volt 700 mA heater and is fitted with an IO base cap.

The construction is a pentode with three wire grids. The slip-coated heater looks to be passed through the cathode tube three times making six elements in total.

The classic envelope is 45 mm in diameter and excluding the B7 base pins the length is 100 mm.

References: Data-sheet, ¹⁰⁴⁰ & ¹⁰⁴³. Type 7D5 was first introduced in 1938. See also 1938 adverts.

Pin Connections

B7	1	2	3	4	5	6	7
	nc	g1	g2	h	h	k,g3	a

Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	Pout	D
	13.0	0.315	285	285	-20	38	7	78k	2.55	4.5W	9%

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated January 03, 2022.

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