Diode and Pentode model

[Federerer]

FYI I'm working on implementing pentode and diode models. Are you interested in merging? Later I'll add some example circuits and maybe some models to the Tubes.xml file and also some documentation and references to the source papers that I used. Currently this branch is a POC 😉

[Federerer]

I think it's as ready to merge as it'll ever be. It has been working fine for me for some time now. Some stuff, like arc drawing API is rather ugly, but I won't be able to do much better without bigger refactoring of how we perform coordinate transformations (which I tried on the side, but I don't want to mix-up things here). I also wanted to implement some more sophisticated transformer and speaker models because this: looks a little messy. But again, this will be done in separate PR. I hope you'll find some time to review it. If something needs to be fixed before merging please let me know ;) P.S. I've posted some new circuits to play with here: livespice-circuits

[dsharlet]

I just checked out this branch and played around with it a bit. A few things I noticed:

• When adjusting pots during simulation, the simulation log gets spammed with Vector hardware acceleration enabled. Should we log that only once per simulation window opening? Or maybe just not at all?
• The pentode symbol is a bit unwieldy with the half-grid-aligned terminals. A few ideas:
• • Is it reasonable to have the extra row of dotted lines that isn't connected to a terminal between the two "live" terminals? I don't really understand vacuum tubes beyond triodes, so I'm not sure what this would mean :)
• • Even then, that first solution is just kicking the can down the road. Maybe we should just double the resolution of the grid.
• In the Fender Se3 example, it seems like the two pentodes (tetrodes?) are misaligned vs. the rest of the schematic.
• Revisiting the pentode vs. tetrode conversation: Is the only reason we're calling this a pentode because the model implementation is the same between a pentode and a tetrode? I wonder if that might be confusing, I suspect most users won't know or care about the internal modeling implementation, and might be confused by a tetrode that is called a pentode?

[Federerer]

• Vector hardware acceleration enabled was used for debugging, we can remove it now, or change level to 'verbose'
• That dotted line is a g3, it does not have a terminal, because known pentode models assumes that it's connected to cathode and as is it's equivalent to tetrode. Some of the pentodes, like EL84 have g3 and cathode connected internally. All popular beam tetrodes like 6L6 or KT88 have beam-forming plates internally connected to cathode. Side note: beam tetrodes were developed as a way to circumvent Philips patent on pentodes, so there are many similarities between them and that's why they can be simulated using the same model. Maybe it would be a good idea to create a separate symbols for pentodes and tetrodes?
• About spacing and symbol, this is my third iteration, I've tried different (bigger) spacing and it always looked weird and way to big and hard to wire neatly because of that. Current symbol is somewhat similar to what you might see on schematics and in other schematic drawing tools.
• Looks like I forgot to replace the Fender example with the new version. Some up to date examples are here: livespice-circuits

[dsharlet]

Thanks for the fixes. This looks good to merge as-is to me. The Fender Se3 circuit still has some missed terminal connections, but I'm fine with updating that after merging :)

I did some testing with the grid = 5 setting. I think it's fine. It's a little weird that the visible grid doesn't match where you can put things, but I think it's not that bad, and probably the best we can hope for for the time being given my lack of forethought in planning the grid and component symbol layouts.

I'm approving this for now, but I'll wait to merge it until I hear from you that it's ready. I'm not sure if you still had some tweaks in the works. If I don't hear otherwise, I'll merge it later this week.

Sorry for the slow review, and thank you again for this contribution, this is really cool!

[Federerer]

5e3 is fixed. Tweaks will be made in separate PR's.