Online Spice Simulator for guitar effects

erelguitars

New member
Hi there

I know there are some platforms out already that work nice - and Brian Wampler (pedalspice.com) just launched a version (I've not used it so I don't know what it does).

I've been working on an own implementation on such a spice-simulated web-solution on the past weekends. To be fair, I've built it using claude (so yes, it's mostly vibe-coded) - I am a Software Engineer, so I do understand the code but I'm more interested in the output here.

It's free for use - it will stay free (I'm not planning to make money out of it!)

So if you like you can register at https://www.circuitstomp.com and give it a go.

Circuit Stomp – key features
  • Draw: schematic editor in the browser with a large part library, from resistors and op-amps to valves, plus ready-made blocks such as tone stacks and gain stages.
  • Simulate: SPICE-style solver with frequency response, waveform, spectrum, and operating point, updated live as you edit or turn a knob.
  • Listen: play a guitar recording or your own audio file through the circuit, or run it in real time on the audio input.
  • Compare: several knob and part settings side by side, and named project versions (V1, V2 …) to switch between.
  • Pedal view: every circuit appears as a pedal or amp with working knobs, in an enclosure you can design.
  • Share: projects saved per account (non shareable at the moment), global example circuits, import and export for KiCad and SPICE.
There are two user-categories
  • Basic user: Ability to store 20 private projects, upload 5 audio-files (mp3 up to max 4 MB / File), create blocks, have 20 versions per project
  • Extended user: (additional to basic user) unlimited private projects, upload 20 audio-files
Currently there is no way to update to extended user - there is no plan for a paid membership. I just wanted to have some limit so that my server won't get flooded. If you reach the limits, drop me a message in the app and I'll be promoting you to extended user.

If there is a problem or if there are suggestions for a feature, please leave it directly in the app (there is a feedback button at the top).

Limits:
  • its only a simulation - so the best it will give you is an indication
  • I'm doing this in my spare time, so don't expect instant responses - but I'm happy if I get feedback :-)
  • some ICs/Parts are not tested (delay, control, cmos, optocoupler for example) - maybe you are experts in these fields - I'm not (I just have fun building/tweaking effects)
  • also guitar-amps work, but they require lots of power, the jtm45 circuit that I included runs at the very limit on my machine (which is not a bad one).
  • Performance-wise I have no idea, how it works on less-powerful machines


Some impressions of the webapp

Live-Preview
  • Use a given mp3, upload your own mp3 or have your guitar directly routed through
  • Have multiple variants with different settings - you can switch through them while in live mode (or switch it off to hear the original sound)

1791724174264.png
  • Change certain values on a variant to - for example - A/B what a cap-switch / res-value change would do (Values .. button)
  • If the circuit is too demanding, live mode probably wont work (you see the load-%) you can also generate clips for all of your variants - they wont respond to instant changes but you can still switch through them

Pedal
  • Design the look of the pedal
  • Give it a back-color, change the knobs, select the enclosure
  • align buttons/switches/texts on the pedal
  • Add additional text
1791724501906.png

Schematic
  • Draw your schematic or import it using a kicad-file (this does not work 100% correct - at least not for all cases)
  • use given blocks
  • add notes to a region
  • export it to kicad (this is untested at the moment)
1791724611143.png

  • Make several version for your effect, so you can get back to an earlier version if your changes are bad
    1791724755318.png

best regards and greetings from Switzerland
Daniel
 

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Last edited:
Quick update, I added some features I do like:
  • Demo mode (so need to have an account)
  • several guitar samples to test the pedals against
  • Signal-Path display
    1791899905404.png
  • Analysis tab to analyze frequency-levels on value changes / pot-changes
  • Warnings when there are errors in the schematic
  • Speaker-simulation with some built-in IR files
  • multiple effects in one (so for example separate boost and overdrive circuit)
  • Compare of several different effects
    1791900131971.png
If anyone has further input / feature requests, please let me know.


That is sick! Where in Switzerland?
Nearby Rappesrwil (I sent a contact-message on your website)
 
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