DY87 @ The Valve Museum

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DY87

Sensibly equivalent^¶ to:

152A 1S2A 1S2 DY86

See also:

Valves and their Habits

Extras ▼

Mullard The Hampshire Collection Other DY87 exhibits

The DY87 is a television EHT rectifier introduced in 1956. This exhibit carries the later Mullard logo and so dates to 1970 or later.

The DY87 was designed to have its heater supply produced by an overwind on the line output transformer. The 18,000 Volt rating places this as a rectifier for medium sized monochrome televisions.

Electrically the DY87 is identical to the DY86. The DY87 has the glass treated with silicone to improve insulation in humid environments.

The bell anode connected only to the top cap.

The central cathode tube with oxide coating and the heater leads. In shadow is the support that holds the top of the cathode in place.

The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 66 mm tall.

References: Data-sheet & ¹⁰⁴⁰. Type DY87 was first introduced in 1955. See also 1955 adverts.

Pin Connections

B9A	1	2	3	4	5	6	7	8	9	tc
	h,k,s	h	ic	h,k,s	h	h,k,s	ic	h	h,k,s	a

Absolute Maximum Operating Conditions^¶

Rectifier	Vh	Ah	Va	mAa
	1.4	0.55	18,000	0.15

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated November 13, 2025.

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