# 24LA v0.3.0

24LA is a Windows x64 optical leveling-amplifier plug-in inspired by the operating principles of the classic LA-2A. It is an original implementation and is not affiliated with or endorsed by Teletronix or Universal Audio.

## Install

Copy the entire `24LA.vst3` folder to:

`C:\Program Files\Common Files\VST3\`

Then rescan plug-ins in your DAW. The standalone `24LA.exe` can be run directly without installation.

## Controls

- **GAIN**: amplifier/output level. The 50 position is nominal unity; higher settings drive the modeled tube and transformer stages harder.
- **PEAK REDUCTION**: side-chain drive and therefore the amount of gain reduction.
- **COMPRESS / LIMIT**: selects an approximately 3:1 compression slope or a steep limiting slope.
- **METER**: three-position rotary selector for OUTPUT +10, GAIN REDUCTION, or OUTPUT +4.
- **POWER**: click-free 25 ms modeled bypass transition.

The stereo build uses linked gain reduction, preserving the stereo image. Mono and stereo DAW layouts are supported.

## v0.2 visual update

- Selected photoreal VOX-style chicken-head knob rendered from a transparent RGBA asset.
- Photoreal metal toggle-switch states.
- Plate-only plug-in window with the surrounding white photo background removed.
- VU needle pivot and counterweight contained inside the meter glass.
- Subtle warm meter-lamp flicker and a separate power/compression activity jewel lamp.

### v0.2.1 layout calibration

- Restored the original long VU needle geometry with its pivot hidden behind the lower meter bezel.
- Raised LIMIT/COMPRESS and POWER switches by 2 mm and enlarged them by 3 mm.
- Lowered GAIN and PEAK REDUCTION knobs by 7 mm and enlarged them by 10 mm.
- Replaced the drawn activity light with crossfading photoreal unlit/lit amber jewel assets and raised it by 2 mm.

### v0.3 optical monitor

- Replaced the photographed analog scale and needle with a smoked-glass T4 optical monitor.
- Mode-aware segmented bar and numeric readout share one exact mapping, eliminating scale/indicator misalignment.
- GAIN REDUCTION reads 0–20 dB; OUTPUT modes read -20 to +3 VU with +4/-18 dBFS and +10/-12 dBFS calibration.
- Added peak hold, overload coloration, optical afterglow and subtle glass reflections.
- Raised GAIN and PEAK REDUCTION by 4 mm and both toggles by a further 1 mm.

## Model notes

- Feed-forward electro-optical topology: signal energy drives a virtual electroluminescent panel; its illumination changes virtual CdS conductance.
- Approximately 10 ms complete-system attack response.
- Multi-state, program-dependent release: a fast first stage near the documented 60 ms half recovery plus progressively loaded 1–15 second trapped-charge states.
- Soft-knee optical control law, 40 dB maximum modeled reduction, and distinct COMPRESS/LIMIT slopes.
- Transformer/tube coloration uses low-order memory and asymmetric saturation. It is intentionally subtle at normal level and increases with GAIN.
- The VU uses a 300 ms-class averaging detector and a damped second-order galvanometer animation with small overshoot and mechanical end stops.

## Validation performed

- Release x64 compilation with JUCE 8.0.12 and MSVC 19.51.
- Automated checks for Peak Reduction off, COMPRESS/LIMIT ordering, program-dependent multi-stage release, and VU ballistic range.
- VST3 bundle metadata generation and standalone launch smoke test.

## Licensing

The included 24LA source is original. Building or distributing it with JUCE requires compliance with JUCE's AGPLv3 or commercial licensing terms. The supplied faceplate artwork belongs to its owner and is included for this project at the user's direction.
