Hi Bryce,
Can you measure the five voltages marked A~E shown in the image using a DC meter, with meter black(negative) lead connected as shown. You should have the ECC82 in place and wait until the filament is fully orange before making the measurement and make sure the measured voltage is stable. If you see the tube plate growing red, switch off to let it cool before making another measurement.
If you measured the voltage in your previous post "without" the tube, you will get high voltage like 330V. The 270V is the nominal circuit working voltage when the tube is operating.