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.

Tube preamp with 6A2 shematic?

Hello everyone.
I need schematic or circuit of this tube preamp (buffer) with tube 6a2 or 6j3.
Thanks,

can you add a tone control before the input on the 6J1 tube version?