if you are getting the same voltage on both sides of your 100k resistor, and the resistor is good, then your tube is not conducting. it could be a bad tube, or the cathode resistor not being grounded. whats the voltage on pin 3.
also you should read 1M from tip to ground with a plug in the jack, but not plugged into an instrument. when you unplug from the jack it should read 0 ohms from tip to ground.