Sensibly equivalent¶ to:
The 33A/158M is a 12 Watt anode dissipation transmitting double triode. The required drive is 1 Watt and the output is 15.5 Watts at up to 100 MHz.
There have been topics in on-line forums about using this double triode as an audio amplifier. Sadly there is little operating data to find. By chance I was reading about the 33A/100A and the major characteristics suggest that the 33A/158M was virtually the same design but on a B8B base. The 33A/100A has a data-sheet,. giving ratings for audio use. Output is 1 Watt with the two sections in parallel or 1.2 Watts when used in push pull class A. Moving to Class B, the output can be 12 Watts.
One anode face view with the grid visible above the lower mica.
The wide glass tube envelope is 28 mm in diameter, and excluding the B8B base pins is 63 mm tall.
Absolute Maximum Operating Conditions¶
Updated May 26, 2020.