This thread will be a place for tube warm up thermal measurements. I use the following instruments for temperature measurements: 1. FLIR E4 2. Fluke 62 Maxx 3. K-type bead thermocouple with Fluke 80TK and Fluke 189 DMM (added 20180116) 4. Keysight E2308A thermistor temperature probe 5. Omega OS136-1-MV infrared sensor D:S=6:1 field of view 6. Picotech Picoscope 2205A with PicoLog Recorder SW for data logging I will add to this collection as I gather more data. Continuous IR temperature measurement logging system: (added 20160116) The following five temperature measurements were made manually with the FLIR and Fluke instruments: Svetlana 6D22S Sophia Electric 6SL7 The following measurements were made using the system shown in the picture above: (added 20180116) During the measurement period a fan turned on to redistribute heat through the room. Bet everyone can find both fan on and fan off times. A continuous data logging system is conducive to measuring all sorts of changes.