The 13D3 double triode can be both a voltage amplifier or an audio output valve. In the latter role it is designed for class B audio push-pull amplifier service. With 45.3 Volts of peak to peak input signal fed in antiphase to the grids the output would be 6.7 Watts at 11% distortion. Loud but not hi-fi. The anode load a-a needs to be 20,000 Ohms. The second set of parameters apply. This operation harks back to the 1930s and quiescent push-pull in battery receivers.

The 6158 is a special quality version of the 13D3.

The 6.3 Volt heater rating assumes that both heaters are fed in parallel. In series they are powered from 12.6 Volts from vehicle supplies. It is possible that the audio output duty was designed for in vehicle applications.

The thin glass tube envelope is 19 mm in diameter and, excluding the B9A base pins, is 47 mm tall.

 
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)	hct

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	6.3	0.65	250	-4.6	6.0	14,000	2.3

Triode	Vh	Ah	Va	mAa
	6.3	0.65	250	21.6

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 04 June 2007 {find valves by name}