PJ was asked if a 6N1P could be used instead of a 12AT7 in the Paramount -
Yes, several of the "usual suspects" can be substituted in the Paramount driver circuit. Assuming a 300B version, the 6N1P will need about 5v of bias if you keep the driver and shunt reg currents the same. You can use the unused 431 chip regulator on the PC board to obtain this bias - or just use a 1500 ohm cathode resistor, bypassed.