WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
Here's some data for the 12AT7. The plate voltage only goes up to 40V due to equipment limitations. To see the full precision numbers, you may need to change the number format display under cell properties.
Here is some 12AX7 data in excel format, as requested. I do not know if this is data I measured myself, or whether it is taken from a spec sheet. I usually record the source but sometimes I get lazy and dont bother.
I notice that in the reply to post form that .xls is not a valid extension, so I am making it a zip file. Also, since it is not really very much data, I simply list it below.
By the way, I am not sure how to tell if the file has been successfully attached to my reply. Perhaps more experienced posters can comment ?