Slate Digital announces the SD-3A VRM Module Optical Compressor

The SD-3A is a VMR module that recreates the Teletronix LA-3A leveling amplifier, a feedback optical compressor developed by Urei in the late 1960s. The company used the UAD re-issue as a hardware reference.

Cut Quick. Punch Hard.

If You’re Chasing “That Sound,” Stop Here.

Inspired by a ‘60s optical legend, SD-3A delivers fast, musical compression with punchy, mid-forward tone and effortless control. Perfect for vocals, guitars, and drums.

Compression That Moves With You

Locks in. Fast.

Whether it’s vocals, guitars, or drums—SD-3A gives you instant control with a sound that’s tight, focused, and musical. Its fast, program-dependent response makes it easy to shape dynamics without overthinking settings or breaking your workflow.
Makes Tracks Pop Instantly

With fast, musical compression and a mid-forward voice, SD-3A adds punch, energy, and movement—without over-processing. Drop it in and feel the lift.
Just the Right Amount of Character

Clean when you want it. Colored when you push it. SD-3A adds shape and attitude without ever sounding overdone—making it perfect for everything from subtle smoothing to aggressive shaping.
Built for Virtual Mix Rack

SD-3A is a compressor with a unique character, making it an excellent addition to the expanding palette of modules available in Virtual Mix Rack. Pair it with your favorite EQs, saturators, and other VMR modules to build a powerful, mix-ready chain in seconds.

Tighten vocals, punch up drums, or shape guitars—without jumping between plugins.

One Rack. Endless Combinations. Total Control.

Fast by Design. Musical by Nature.

Program-Dependent Precision

SD-3A listens to your source. Its attack and release adapt to the signal in real time, offering smoother control on vocals, and faster grip on drums or guitars. No need to tweak endlessly. Just mix and move on.
HF / Flat Sidechain Filter

The HF knob boosts high-frequencies on the internal sidechain, thus applying more compression to high frequencies. This can be used to tame and smooth bright transients when the audio needs to sit deeper within the mix.
Optical Meets Solid-State

You get the best of both worlds: the tone-shaping character of optical compression with the snap of a solid-state signal path. It’s fast, focused, and never fuzzy.
Built-In Mix Control

Parallel compression is just a twist away. The Mix knob lets you blend in exactly as much compressed signal as you need. No extra routing, no duplicate tracks, just results.

Curious what makes SD-3A tick?

Get the full backstory, tech deep dive, and mix tips straight from our engineers.

“The SD‑3A is the first LA‑3A plugin that actually feels like the hardware… smooth, musical compression with just the right midrange presence and natural dynamic response. Instantly my go-to for vocals, bass, and anything that needs controlled energy without losing punch.”

Matthew Kutoloski

Mixing & Mastering Engineer for ovg! and LOVELI LORI

Get SD-3A through any Slate Digital subscription or as a perpetual license.

Slate Digital SD-3A is available now for $99.00

For more information please visit: https://slatedigital.com/sd-3a-compressor-plugin/









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