This interesting circuit requires a triode-hexode with no internal connection between the two sections (other than a shared cathode).  Most triode-hexodes aren't built this way, but a double triode can be used instead. Though I've yet to test it, this circuit might work with a triode-pentode such as the ECF80.

Although there probably weren't many commercial amplifiers that used triode-hexode phase splitters similar circuits were published from time to time.  An example appears in the datasheet for the ECH42
Michael Saunby,
15 Aug 2009, 15:13