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.
I have 12SN7’s installed in the octal Aikido I use(B+ := 300). I assembled the PCB thinking that I may try rolling in 12SL7’s at the input position. I have 1000 ohm resistors installed at the input position and 300 ohm resistors installed at the outputs. The 12SN7’s provide adequate gain. I never rolled in the 12SN7’s. The 1000 ohm resistors remain. I have never given them a thought until you ask. The 300 ohm resistors allow a little more current to drive longer interconnects.
All Just for fun!