Application for Windows PC

Get the “DCTriode” free PC app, far better than the Web site

I maintain a Windows PC application “DCTriode”, freely available for download and usage (freeware license): more comfortable, more circuits, more tube models, more features than the Web version. Pure freeware, fully functional, without any advertisements, telemetry, spy or intentional virus-like functions.

You may download its user manual to figure out what are its features

  Online library PC application
Circuits 10 35
Include triode models ECC81 ECC82 ECC83 ECC88 ECC81 ECC82 ECC83 ECC85 ECC86 ECC88 ECC99
ECL81 ECL82 ECL83 ECL84 ECL85 ECL 86
12AY7 300B 2A3
Include pentode models none EF86 (release 2.0 spring 2023)
Customise, create tube models no yes
Display anode curves basic more detailed
Display µ gm ri no yes
DC data yes yes
Graph stacked voltages yes yes
Graph DC loadline no yes
AC gain and impedance no yes (not for all solvers)
Frequency response no with Miller effect and stray capacitances (release 2.0 spring 2023)
Single-ended and push-pull stages with power triodes and pentodes no release 2.1 fall 2023
Store and retrieve circuit configurations no release 2.0 spring 2023
Store results for spreadsheet no yes
Library interface fixed flat / tree
PDF User Manual no yes

Freeware license

DCTriode is a freeware: you may download and use it freely for an unlimited period of time; meanwhile, you are not authorized to sell it. Its code remains proprietary.

Download it freely now

Download from . Note that your browser may prevent you to download this MSI file, to “protect” you…

Last release #1.9 (February 6th 2023).

Available circuit solvers:

  1. Basic common cathode stage
  2. Phase inverter, self bias cathodyne
  3. Cathode follower, fixed bias
  4. Gain stage and DC-coupled cathode follower
  5. Phase inverter, fixed bias cathodyne
  6. Cascode
  7. Differential phase inverter, cathode bias
  8. Cascode SRPP
  9. Gain stages with direct coupling
  10. Differential phase inverter, constant current bias
  11. Dual triode mixer, balanced
  12. Dual triode mixer, asymmetrical
  13. Gain stage, constant current bias
  14. Gain stages with DC level shifting
  15. Differential phase inverter, long-tailed pair, cathode bias
  16. 2-triode serial voltage regulator
  17. 1-triode basic serial voltage regulator
  18. 1-triode shunt voltage regulator
  19. Three gain stages coupled by HV RC filters
  20. Two gain stages coupled by HV RC filters
  21. Double-cascode after “Aikido” circuit (
  22. Cascode SRPP after phono preamp (
  23. Push-pull amplifier with DC feedback (
  24. SRPP headphone amplifier (after
  25. Basic current source
  26. Constant-Current-Draw-Amplifier (after
  27. Janus cascode shunt regulator (after
  28. Totem pole split load phase splitter (after
  29. Amplifier with AC local feedback anode to grid
  30. Mu-follower
  31. Cascode SRPP+
  32. Common-grid amplifier
  33. White cathode amplifier
  34. Half-mu stage
  35. Cathode-follower with current sink

Library of circuits
common-cathode amplifier and DC-coupled cathode-follower
small signal estimate
models of tubes

Displaying anode curves

anode curves

Drawing transconductance, internal resistance and amplification factor of the ECB88 / 6DJ8 at 3 different anode voltages:

transconductance, internal resistance, amplification factor