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Help modeling triode with heater

Posted: Wed Nov 12, 2025 4:46 pm
by RFMed
Hi, I am trying my hand at recreating the demo on https://www.duncanamps.com/technical/ltspice.html. However, there was no link to the generic triode model which I assume has the heater element in the .SUBCKT file. I am getting confused on how to implement the heater and would greatly appreciate any feedback. I understand the cathode, grid, and anode portion but do not know how to incorporate the filament into the code.

Thank you all for your assistance

Re: Help modeling triode with heater

Posted: Wed Nov 12, 2025 6:22 pm
by duncanamps
Hi,
However, there was no link to the generic triode model...
I withdrew the Generic Triode model as it had some real accuracy issues. Not sure if I would re-visit it, as there are probably a lot better models out there since I put the model together 28 years ago.

However, the documents are still there:

There's the Version 2 model which seemed to work well, it would be worth you having a read of that as it explains how it all operates, contains the model listing, heater model etc.

Also, there's the Version 3 model which looked OK to start with but turned out to have problems. Can't remember what the exact problem was, but it was bad enough for me to pull the plug on it. Just including this one for information.

Regards,
Duncan

Re: Help modeling triode with heater

Posted: Mon Nov 17, 2025 9:18 pm
by RFMed
Hi Duncan,

Thank you for the help! Greatly appreciated.

Thanks again