The Pen220A from Mazda is a battery output pentode from the 1930s.

The anode load impedance is given as 6,000 Ohms and it would generate 1.1 Watts of audio at 7% distortion.

The wide spaced wire grid structure can be seen from the top of the dome as the anode cavity has an open top. The filament is a double inverted V.

The balloon envelope is 45 mm in diameter and, excluding the B5 base pins, is 96 mm tall.

 
Pin Connections

B5	1	2	3	4	5
	a	g1	f(-)	f(+)	g2

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm	Pout	D
	2.0	0.2	150	150	-9.0	18	3.6	270,000	2.2	1.1	7%

More

This exhibit was last updated on 04 October 2006