This month we have a look at a 9 pin miniature medium mu triode, the 6S4A.
This tube, like so many, was developed for use in the deflection system of TVs but can serve in other applications as well including AF amplifiers.data sheet and decide for yourself if it is worth to give this tube a try. As always we compare the data sheet plate curves with those of an actual tube:
And here a few samples, starting with RCA:
Some close up shots:
Higrade branded 6S4A:
Westinghouse in military box:
And lastly a few photos of the tube in operation: