Working on the valve aims now...

...sims...!

@kgreene1983, All the example tube/valve types listed in: [https://easyeda\.com/andyfierman/Valve\_Tube\_examples\-05ZhzR9rJ](https://easyeda.com/andyfierman/Valve_Tube_examples-05ZhzR9rJ) now work. Note that this list includes a 12AU7 model.

I've updated the project, adding a sheet to show where to find and use the valve/tube symbols in simulation with the list of available spice models. Please revisit: [https://easyeda\.com/andyfierman/Valve\_Tube\_examples\-05ZhzR9rJ](https://easyeda.com/andyfierman/Valve_Tube_examples-05ZhzR9rJ)

The following models have bee added to the list as they simulate correctly in LTspice: SV6AS7_DM NHSV6AS7_DMGTM NH2A3_DMGTM NH6DJ8_DMGTM SV5723_DMGTM

I just want to say thank you for all of this. I've wanted to build a tube pre-amp for many years. I've built pre-amps in the best by breadboard, but this has made it so much easier to experiment. Thank you so much for your help! PS the cheat sheet doesn't let you copy the symbols

So... the 12au7 can run on 12volts, anything below 100v this happens. Is this model working correctly? 

I'll have another look at the model but remember that the circuit in the example is just a generic setup. You have to use the relevant valve data sheets (wherever you can find those) to set up the grid biasing and load lines appropriately. I have seen  some stuff about using valves at low voltages but can't remember where. I'll post if I find it. In the meanwhile this might be of some interest:

Well it would if I included the link: [https://easyeda.com/andyfierman/180501](https://easyeda.com/andyfierman/180501)

You may not get good modelling of valves in the low voltage (starved) region because they were developed for the more usual high voltage applications. This is possibly confirmed by the article I mentioned and have found again: [http://rezzonics.blogspot.com/2017/05/korg-nutube-6p1-vs-12ax7-starved-tube.html?m=1](http://rezzonics.blogspot.com/2017/05/korg-nutube-6p1-vs-12ax7-starved-tube.html?m=1) You could try contacting Duncan Munro about using his models in the low voltage region. BTW, I haven't tried it but if you want to get really stuck in you should be able to run Norman Koren's Matlab scripts on  the FOSS Octave package: [https://www.gnu.org/software/octave/](https://www.gnu.org/software/octave/) [https://octave-online.net/](https://octave-online.net/)

@kgreene1983, The cheat sheet should let you copy and paste the symbols. Please see this topic: [https://easyeda.com/forum/topic/HOW-TO-COPY-COMPONENTS-b04a5a1d2db043309efbddd98a398f13](https://easyeda.com/forum/topic/HOW-TO-COPY-COMPONENTS-b04a5a1d2db043309efbddd98a398f13)

On the subject of using valves at low voltages, when JFETs first became readily available, a lot of people who had grown up with valves got excited about the fact that they behave very much like triodes. [https://www\.radiomuseum\.org/forum/the\_trioderizer\_a\_solid\_state\_triode\.html](https://www.radiomuseum.org/forum/the_trioderizer_a_solid_state_triode.html) [https://audiokarma.org/forums/index.php?threads/heresy-making-a-jfet-act-like-a-triode.262773/](https://audiokarma.org/forums/index.php?threads/heresy-making-a-jfet-act-like-a-triode.262773/) [https://tapeop.com/interviews/37/diy-jfet-mic-pre/](https://tapeop.com/interviews/37/diy-jfet-mic-pre/) [http://www\.hawestv\.com/amp\_projects/design\_page/fet\_curve\_dsn1\.htm](http://www.hawestv.com/amp_projects/design_page/fet_curve_dsn1.htm) And a bit off-the-wall... [https://medium.com/@tom_a/using-vacuum-tubes-to-learn-jfets-4cdb95c99e22](https://medium.com/@tom_a/using-vacuum-tubes-to-learn-jfets-4cdb95c99e22) [http://www.aquinaudio.co.uk/valve_em.html](http://www.aquinaudio.co.uk/valve_em.html) [http://milas.spb.ru/~kmg/tubeemulation_en.html](http://milas.spb.ru/~kmg/tubeemulation_en.html) [https://en.wikipedia.org/wiki/Fetron](https://en.wikipedia.org/wiki/Fetron) And that's why there's one at the front end of myTesseract amplifier design: [https://easyeda\.com/example/Tesseract\_Guitar\_Practice\_Amp\-MjP71jBni](https://easyeda.com/example/Tesseract_Guitar_Practice_Amp-MjP71jBni)