• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Schematic.... 801a/211

801a (gain: 8) unable to drive 211 without some "help".

211 grid requires 140-150Vpp swing (depends of B+ and operating point) to A1 (about 16W at 10-12k OPT).
If you use -good- 1:4 SUT before 801a (and interstage to 211), the requiring input volume exceeds 2.1-2.2 VRMS.

1_4 SUT, 801a, IT, 211 SE 10k.jpg
 
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If the different brands tubes are similar -not exactly "standard" GE 211/VT-4C compatible, but similar- and possible to set desired operating point (variable bias voltage), and the driver has enough headroom to serve -a little- different grid swing requirement, it would be possible.
 
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