So many exciting ideas to try out as an alternative to the 5842 driver in my 1626 amps. Besides all the high-gm little triodes I have, the pentode fettish has peaked my curiosity. Sometime last decade I bought some pentodes already, which makes me think I wanted to try some even back then but never got around to it. So a good opertunity to make good on that. Some candidates will include Mullard E180F, WE 404A/5847, Siemens D3a, Amperex 6688, Philips E810F and the russian 6E5P, 6E6P-DR(U), 6J9P, 6J11P, 6J49P-DRU. On the triode front they will compete versus the Raytheon 5842Q, Siemens EC8010, WE 437A and russian 6S4P-DR, 6S45P-E, 6N30P, 6H6P.