you might have open loop gain (zero feedback) when your switch is set on 9, so make sure you have the 40 K after the 2 uf cap that comes off the rotary sw.
i have V1 and V2 mounted on rubber grommets for shock absorbers to cut down on microphonics,
also running 250 volts DC for B+, headroom is not a problem in the first stages as input signal is only around 100 milli volts from mic, in fact, lower plate voltage on Vi will be just a bit more quiet,
you can run anywhere from 47K to 220K for V2 resistor if you are not using a choke here,
here is pic of my V76, could have made it smaller but it is still very quiet, using DC on heaters and non lytic for 4 uf output cap, using original V72 choke for V2 and a DIY choke for V4 which is mounted on the other side of the chassis along with the output cap,>
i have V1 and V2 mounted on rubber grommets for shock absorbers to cut down on microphonics,
also running 250 volts DC for B+, headroom is not a problem in the first stages as input signal is only around 100 milli volts from mic, in fact, lower plate voltage on Vi will be just a bit more quiet,
you can run anywhere from 47K to 220K for V2 resistor if you are not using a choke here,
here is pic of my V76, could have made it smaller but it is still very quiet, using DC on heaters and non lytic for 4 uf output cap, using original V72 choke for V2 and a DIY choke for V4 which is mounted on the other side of the chassis along with the output cap,>