If we presume that the 300B needs 70V peak of drive, then using the 1626 to drive it would mean that you will need around 15V peak at the input of the 1626, which is about 10V RMS. You could definitely use the 1626 to do this, but it would need to be in a three stage amplifier. You could probably use two 1626s per 300B with some success.
Kind of; picked them up at an estate sale. The prior owner must have been a tech or DIY enthusiast. There were mountains of transformers, sockets, tubes (I came at the tail end of this), wire, heat shrink, tools............silver faced gear and on and on.
I regret not stopping by in person sooner as they had the online sale first.
The darling is a very nice amplifier with its 0.5 W. The advantage is that it works very well with a high efficient speaker. It only needs a very small output transformer (EI54) and is attached to the Altec 403A (I'm still testing) in a thin-walled housing (according to Dr.Götz Willimzig. 42–50 l, 9 mm Mpx nachgoldenenm tube 100mm and 50 mm long deep bass miracle is it not, but a very homogeneous music reproduction.