Tube of the Month - The 417A

In this tube of the month’s installment our friend Thomas focuses on the other end of the size spectrum; the Western Electric 417A. The 417A is more contemporary tube, that was designed for for grounded grid operation in broad band amplifiers with looks and size (35mm high) similar to 6AM4. 

Western Electric 417A encapsulate its magic in a small, glass bottle mounted on a 9 pin miniature Noval base. WE 417A has unique ability to match required high transconductance tubes and the 417A has plenty of that: 25.000 micromhos or 25mS.

Link: here.