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Learning LT Spice.
Lesson 9

Table of Contents.

Lesson 1: Fundamental Drawing Skills and a Simple Simulation.
Lesson 2: Introduction to Frequency and transient Analysis.
Lesson 3: Configuring LT Spice and more Drawing controls.
Lesson 4: Locating, modifying, and installing vacuum tube models.
Lesson 5: Operating point of vacuum tube circuits. Introduction to stepping and plate curves.
Lesson 6: Finding, installing, and using, potentiometer symbols and models.
Lesson 7: Transient analysis of unregulated power supplies.
Lesson 8: Transient analysis of power supply regulators.
Lesson 9: Transient and frequency analysis of amplifiers with feedback. This page.
Lesson 10: Lossless transformers.
Lesson 11: Making symbols and models.


Lesson 9
Transient and frequency analysis of amplifiers with feedback.

So where is limbo and why is this page there. To the first question, I don't know. To the second one, well, it's like this.

There are many sites on the web where you can learn about LTspice. But I don't think there are many that are oriented towards those interested in vacuum tube circuits. This set of pages is the exception to that. And that is the source of the dilemma in which I find myself. The amplifiers that you will want to design to be stable are power amplifiers which always contain an output transformer. There wouldn't be much point in designing a feedback loop that is stable with an ideal transformer. I haven't yet learned how to make measurements on a real output transformer and then turn them into a spice model.

In lesson 10 you will learn how to add an ideal transformer to a circuit. In some cases that can be useful but not for the output transformer in an audio power amplifier. This page will remain in limbo until I learn how to model a transformer. Meanwhile, if someone out there who is younger than I am and therefore can learn more easily and quickly than I can, would like to model the popular Hammond and Edcor output transformers , have at it.




This page last updated Saturday, May 21, 2022.

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