Tools Tonestack PSU Designer Load Lines Tube Data Build Planner Specs
Apps
StringsTheory INV Tech Tools Design Privacy Edition
Support
Support Contact Submit Feedback
Legal
Privacy Policy Terms of Service EULA
StringsTheory Design

Circuit analysis for
tube amp builders

Five precision tools in one app — tonestack calculator, PSU simulator, load line plotter, tube database, and build planner. Native on Mac and iPad.

macOS 15.7+ · iPadOS 18.0+ · One-time purchase · No account required · Works offline

Tonestack Calculator on Mac Tonestack Calculator on iPad
53
Tone Circuits
173
Rectifier Models
3,727
Tubes
479
Amp References
346
Verified Fuse Values
Tools

Five tabs. Everything you need.

Each tool is purpose-built for tube amplifier design and analysis.

See the tone before you build

Real-time Bode magnitude and phase plots for 53 guitar amp tone circuits across 9 categories. Adjust virtual potentiometers with realistic taper curves and see the frequency response update instantly.

  • ✓ 53 tone circuit models — Fender, Marshall, Vox, Dumble, Baxandall, James, Big Muff, Boss, and more
  • ✓ Log A/B/C and linear pot tapers
  • ✓ Compare multiple tonestacks with overlaid curves
  • ✓ Square wave oscilloscope via state-space simulation
  • ✓ Save and load configurations as JSON
Tonestack Calculator on Mac Tonestack Calculator on iPad

Simulate your power supply

Time-domain simulation using Euler integration with Newton-Raphson convergence. Design filter chains, compare rectifier topologies, and see voltage ripple and current waveforms in real time.

  • ✓ Full-wave CT, bridge, voltage doubler, half-wave topologies
  • ✓ 173 rectifier tube models with manufacturer I-V curves
  • ✓ Configurable C, RC, and LC filter stages with ESR
  • ✓ Off-load voltage and ripple estimation
  • ✓ Load and save in PSUD2-compatible .psu format
PSU Designer on Mac PSU Designer on iPad

Find the operating point

Plot plate characteristic curves for EL34, 6L6GC, 6V6GT, 300B, and dozens more. Overlay DC and AC load lines, drag the Q-point, and see power dissipation update live.

  • ✓ Koren triode, pentode, and unified tube models
  • ✓ Single-ended and push-pull topologies
  • ✓ Resistive and reactive (transformer) loads
  • ✓ Automatic cathode bias operating point
  • ✓ Power dissipation and output power estimates
Load Lines on Mac Load Lines on iPad

3,727 tubes at your fingertips

Search by designator, category, or base type. Every entry includes heater specs, maximum ratings, operating conditions, and pinout diagrams. Rectifier tubes include verified max input filter cap ratings.

  • ✓ 3,727 tube entries across 11 categories
  • ✓ Visual pinout diagrams (Octal, Noval, Compactron, Rimlock, and more)
  • ✓ Heater voltage/current, max plate voltage, max dissipation
  • ✓ Safety-critical filter cap ratings verified from manufacturer datasheets
Tube Data on Mac Tube Data on iPad

Plan the build, match the transformer

Load a Fender Deluxe Reverb, Marshall JCM800, or any of 479 amp presets. The calculator shows heater rail currents, B+ requirements, and recommended mains fuse, then matches against transformer catalogs.

  • ✓ 479 amplifier references across 30 manufacturers
  • ✓ Verified mains fuse data for 346 models
  • ✓ Transformer matching — Hammond, Edcor, Mercury Magnetics, Pacific
  • ✓ Fixed bias, cathode bias, and relay power configurations
  • ✓ Automatic heater rail grouping and secondary synthesis
Build Planner on Mac Build Planner on iPad
Specifications
Tonestack Models53 across 9 categories
Rectifier Models173 with manufacturer I-V curves
Tube Database3,727 entries with pinouts
Amplifier References479 across 30 manufacturers
Verified Fuse Data346 amplifier models
Transformer CatalogHammond, Edcor, Mercury Magnetics, Pacific
File FormatsJSON (tonestacks), .psu (PSUD2 compatible)
PlatformsmacOS 15.7+, iPadOS 18.0+
PriceOne-time purchase
Internet RequiredNo — fully offline
PrivacyZero data collection, no tracking, no analytics

Built for builders

One-time purchase. No accounts. No subscriptions. Just tools.

Privacy Policy  ·  Support  ·  Terms of Service