The 19AQ5 is an audio output beam tetrode. The ratings, except for the heater match the 6AQ5 that is the direct equivalent of the EL90.
Power output is up to 4.5 Watts at 8% total harmonic distortion.
The nearly opaque glass prevents inspection of the construction. The valve is clearly marked as UK made.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 60 mm tall.
References: Datasheet & 1040.
Absolute Maximum Operating Conditions¶
Updated November 25, 2014. shape:thin.glass.tube construction:all.glass type:beam.tetrode age:1950.1960 base:b7g pins:7 pin:1.g1 pin:2.k.bp pin:3.h pin:4.h pin:5.a pin:6.g2 pin:7.g1