I wanted to mess with Vacuum Tubes and learn from old electronics to show my granpa how they worked, specially radio (AM and FM). I downloaded a library of vacuum tubes but could not install it properly or i am missing something.

I am using OrCAD Capture 16.6-2015 Lite

How did i get to the problem?

I downloaded the RAR file containing a .lib and .OLB which i copy pasted into the next directories.

.lib at C:\OrCAD\OrCAD_16.6_Lite\tools\pspice\library


.OLB at C:\OrCAD\OrCAD_16.6_Lite\tools\capture\library

Where is the problem?

When i run the simulation it jumps into this error:

ERROR(ORPSIM-15108): Subcircuit 12AT7 used by X_VL1 is undefined

That means it can not reach the library or some other file? I have read another question about the same problem but still could not solve the thing.


Here is a pic of the schematic if someone is interested of the FM radio with vacuum tubes.

enter image description here

PD: I know the values are not correct or adequate, it was a test to see if it could simulate and i am open to improvements if it a simple change i can understand.

  • \$\begingroup\$ Have you checked if the pins from the symbol match the ones described in the model? \$\endgroup\$ – Radiohead Apr 26 '18 at 8:53
  • \$\begingroup\$ i have checked that with every tube i get the same error. \$\endgroup\$ – WhiteGlove Apr 26 '18 at 8:59
  • \$\begingroup\$ I have no idea how it works with OrCAD, but when I wanted to simulate a design I did on a vacuum tube amplifier I used LTSpice with models from this website: duncanamps.com/spice.html \$\endgroup\$ – Radiohead Apr 26 '18 at 9:08
  • \$\begingroup\$ It's likely that it's a symbol library that doesn't have models associated with the parts. You need models to run simulations. \$\endgroup\$ – Andy aka Apr 26 '18 at 9:45
  • \$\begingroup\$ How i do the model, Andy? \$\endgroup\$ – WhiteGlove Apr 26 '18 at 10:03

Instead download a free version of circuitmaker 2000 here: http://getintopc.com/softwares/simulators/circuit-maker-2000-free-download/

Then get these tube spice models that have been written for audio enthusiasts here and install them into the program which is quite easy.


  • \$\begingroup\$ The initial thought was to use them inside the software i said before, not just audio. \$\endgroup\$ – WhiteGlove May 1 '18 at 16:55

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