Name: Optotron
Brand: Desert Moon Audio
Price: 49.00 USD
Availability: InStock

Optotron OT-2A - Desert Moon Audio plug-in

Electro-Optical Leveling Amplifier

One knob, and the light does the rest

Optotron is an opto compressor plugin for Mac and PC: three classic electro-optical leveling amplifiers on one chassis, each modelled down to the photocell.

14-DAY FREE TRIAL

Full version, free for 14 days. No payment details needed.

Works with all major DAWs

AU / VST3 / AAX for Mac · VST3 / AAX for PC

Yours forever — no subscription

Instant download after purchase

Hear the difference

Press play to hear it through Optotron. Tap DRY for the original, at the same moment.

Drums

Vocals

Acoustic

Bass

Where it goes

Four of the places it lives, each with a demo above.

Drums
Peak reduction on a drum bus levels the hits, and the two-stage release keeps the room swelling.
Hear it
Vocals
The classic job: two knobs, a vocal that sits, and nothing that sounds compressed.
Hear it
Acoustic guitar
Gentle gain reduction that follows the strum, with the sheen of the tube make-up stage.
Hear it
Bass
An opto cell on bass holds the level steady for a whole song without pumping.
Hear it

About Optotron

Optotron is an electro-optical leveling amplifier: the audio drives a light panel, the light falls on a photocell, and the photocell turns the gain down. Everything this kind of compressor is loved for — the gentle knee, the ten-millisecond grab, the release that lets go in two stages and hangs onto long notes — falls out of that one mechanism. Optotron models the mechanism itself, with its fast carriers and slow trap states, rather than tracing curves off a single unit, and a built-in measurement bench holds every figure to the published hardware behaviour on every build.

Three units share the chassis, and switching between them swaps the entire faceplate as well as the sound. SILVER is the modern voicing — the cleanest electronics, extended bandwidth, the quickest recovery. GRAY is the reference voicing — a program-dependent two-stage release and warm push-pull tube midrange. OT-2 is the earliest voicing — slowest and most coloured, deeper release bloom, stronger second harmonic, with the meter selector under the glass and the jewelled power lamp.

Key features

Three units, three faceplates
SILVER, GRAY and OT-2 — each drawn as its own piece of hardware, each with its own electronics, bandwidth and release character.
The cell, modelled for real
A superlinear lamp law onto a photoresistor with fast carriers and slow trap states: the ~10 ms grab, the 50%-in-60-ms first release, the seconds-long program-dependent tail, and the way deep reduction blooms back are consequences, not presets.
Cell Age
Scales the photocell's real physics — a worn cell grabs slower and hangs far longer. Something a curve fit cannot offer.
Loudness-honest Auto Gain
Make-up rides the average reduction slowly, so bypass and Peak Reduction moves compare at matched loudness instead of louder-is-better.
A working sidechain
External sidechain input, a momentary SC listen that auditions exactly what the detector hears, a continuous rumble filter, and Emphasis on the front panel.
The standard service rail
Parallel Mix, stereo link, 4x oversampling through the whole nonlinear path, A/B compare, undo/redo and presets.

Optotron panel, with its controls numbered

The panel at a glance

Limit / Comp Rearranges the sidechain: firm knee or a gentle 3:1.
Emphasis Screwdriver trim that tilts the sidechain toward the highs.
Gain The tube make-up amplifier. Centre of the dial is unity.
VU meter Gain reduction or output, chosen by the meter switch.
Peak Reduction How hard the programme drives the optical cell.
Meter function Gain Reduction, Output +10 or Output +4.
Power True bypass, ramped so it never clicks.
Unit bank Silver, Gray or OT-2: three generations of the circuit, each with its own cell, tube stage and transformer.
Mix, SC HPF, Age Parallel blend, a sidechain rumble filter, and the photocell's age: a worn cell grabs slower and hangs longer.
Link, Ext, SC, Auto Stereo link, external key, listen to the sidechain, and loudness-honest auto gain.

More details

Yes — 14 days, fully featured, from the first time the plugin loads. All three units, every control, no interruptions and no signup. When the trial ends, audio passes through dry until a license is entered, so your sessions always open.

Yes. It's a one-off purchase, not a subscription, and there's nothing to renew. Updates to a plugin you own are free — download the current installer and run it over the top.

Every plugin is sold on its own, so you can buy just the one you want.

Your license covers up to 4 computers you personally own — studio desktop, laptop, spares. Enter the same key on each; the first activation on a machine takes one quick internet check; after that it works offline, apart from a once-a-day check for a newer version. Moving on from a computer? Deactivate This Machine in the plugin's preset menu hands the seat back, and if a machine dies before you can, just ask us.

Your download link and license key are in the order confirmation email sent at purchase. Run the installer, open Optotron, click the trial notice on the panel, paste the key — done.

Can’t find the email? Check spam, then write to info@desertmoonaudio.com and we’ll resend it.

Yes — after activation. Entering your license key needs an internet connection once; from then on it works offline — the only other time it goes online is a once-a-day check for a newer version.