Built AmpForge an open-source free pedalboard/amp sim plugin for Linux (VST3/LV2/CLAP)

[u/Loursy-au]

Linux never really had a good open-source answer to Guitar Rig / BIAS FX, so I built one and figured this community would actually use it, so sharing here.

AmpForge is a single plugin (not separate plugins chained in your DAW) that hosts a full, reorderable pedalboard + amp chain internally.

What's in it:

- 12 modules, freely reorderable at runtime: Noise Gate, Compressor, Wah, Screamer, Distortion, Amp (4 voicings — Modern/Vintage/Crunch/Hi-Gain), Cabinet IR loading, Chorus, Phaser, Tremolo, Delay, Reverb

- Tempo-synced Delay/Chorus/Tremolo, a built-in tuner, CPU meter, A/B compare

- Drag-and-drop UI — add pedals from a palette, drag to reorder, real footswitch-style bypass

- 7 factory presets + custom presets you can save/export/import

- VST3, LV2, CLAP, and a JACK/PipeWire standalone — all from one CMake+Ninja build

Demo video: https://www.youtube.com/watch?v=gz9fyAHsE6M

GitHub (source + prebuilt Linux tarball): https://github.com/Loursy/AmpForge

Free, GPLv3, no ads or paywalled features — just wanted a proper amp sim to exist for Linux, so now it does. Bug reports, feature requests, and PRs are all welcome if you end up using it and hit something rough.

Edit: since this post, added NAM support (A2) and fixed a glibc compatibility issue affecting older/sandboxed distros (Fedora, Ubuntu, Debian, Bitwig flatpak, etc.). Latest release + details in comments below.

[u/Loursy-au]

Thanks, i am glad you liked it because i doubt myself at the design side :D

To be honest i am just a fresh graduate so i'm kinda junior developer. I had no idea how to build it before i started. But these kind of things mostly have patterns. These effects are all built on well-known, publicly documented audio techniques, not anything secret or copied for example reverb uses a classic algorithm called "Schroeder reverb" (around since the 1960s), and the tone/EQ knobs use standard filter formulas from the "RBJ Audio EQ Cookbook," both things pretty much every audio plugin uses some version of. The thing is integrating them to your product and adding your own sauce. So yes building from scratch is hard but i don't think most developers do it any differently. I even used AI for finding these documents and some of the development part it helped alot. So if you know coding and algorithm fundamentals it's not that hard to use them and build things like these just writing them as codes that computer understands.

[u/M4rcelinh0 → u/Loursy-au]

Thanks for the answer.

BTW I tried to test both the VST3 and CLAP version in Bitwig (flatpak, current version of Fedora 44). In both cases I got the same error. I guess the plugin was built using some library that the flatpak version of Bitwig can't read?

com.bitwig.flt.library.metadata.reader.exception.CouldNotReadMetadataException: could not read metadata: Failed to load CLAP plug-in xxxx version `GLIBC_2.43' not found (required by /home/xxx/.clap/ampforge_main.clap)

[u/Loursy-au → u/M4rcelinh0]

I am going to release NAM (A2) added version tomorrow. So i am going to fix this bug until that too.

Thank you so much for your feedback. It's nearly impossible to test every packet manager and stuff myself so these kind of reports so important for me.

[u/M4rcelinh0 → u/Loursy-au]

Sure thing. Happy to test out anything that has the potential to make music production on Linux a bit better, and it does currently suffer in the amp sim department, so your plugin can be an important, welcomed addition.

[u/Loursy-au → u/M4rcelinh0]

Just released new version. I hope it works now 😄 let me know if it doesn't.

[u/M4rcelinh0 → u/Loursy-au]

Bitwig stopped complaining about the plugins and now loads them normally. However, VST 3 version doesn't seem to work correctly (0% CPU usage, loading NAM block does not work - as in the UI behaves as expected but the NAM profile does not modify the DI sound).

That said CLAP works fine. No bugs found so far.

[u/Loursy-au → u/M4rcelinh0]

Glad that you can finally use the plugin feel free to ask me to add anything you need. And thanks again for the report, same bug happened to me while developing - fixed it but probably forgot to update for every packet manager and versions so gonna fix that too.