R1 is a carbon comp, quarter of a watt. Mouser has them cheap from XIcon. value is between 510R and 1k. I have used 510 with no troubles, but if you find 1k to be a useful thing, bet them in qty...

S2 is the Mute, short it out and you won't have to worry about a 'thump' on start up.

There is a mistake!!!!

P1 in the source-gate circuit should be configurd as a variable resistance, tie the end at the plate to the wiper and we'll be fine.
regards,
Douglas