Legendary Tube Opto Compression. Now in True Stereo.

Bring the unmistakable smoothness, depth and musical control of classic Danish tube optical compression to your stereo signal chain with the Stam Audio SA-2B Stereo Tube Opto Compressor.

Designed as a meticulously matched dual-channel evolution of the legendary Danish 1B-style opto compressor, the SA-2B combines vintage-inspired tube tone with the precision required for modern stereo mixing and mastering. From vocals and instruments to drum buses, subgroups and the stereo mix bus, the SA-2B delivers sophisticated dynamic control while helping preserve the width, balance and integrity of your stereo image.

At the heart of the SA-2B is a carefully engineered tube-and-transformer signal path featuring custom US-made input transformers, Swedish-made Lundahl output transformers, selected 12AU7 and 12AX7 tubes, and laboratory-matched optical gain-reduction elements.

The result is the kind of compression engineers reach for when they don't simply want a signal to be quieter — they want it to sound more polished, dimensional and finished.

True Stereo Compression Without Sacrificing Your Image

Running two independent analog compressors across a stereo source can create a serious problem: if the channels don't respond identically, the stereo image can shift as gain reduction changes.

The SA-2B is specifically engineered to address that challenge.

Stam Audio uses a proprietary matching circuit along with carefully matched components to maintain consistent frequency response, tone and time constants between the left and right channels.

Its custom optical gain-reduction elements are laboratory matched so the attack and release behavior of both channels remains closely synchronized.

That makes the SA-2B particularly compelling for stereo buses, drum groups, instrument buses and mastering chains, where stable imaging is every bit as important as musical compression.

Tube Tone Meets Premium Transformer Iron

The character of a premium analog compressor isn't created by one component — it's the interaction between the entire signal path.

That's why Stam Audio equips the SA-2B with two custom US-made input transformers and two Lundahl output transformers manufactured in Sweden.

The transformer pairs are selected for consistency to help maintain symmetrical harmonic character across the stereo field.

Selected 12AU7 and 12AX7 tubes complete the analog signal path, giving the SA-2B the rich harmonic texture, depth and smooth top-end response associated with premium tube compression.

Whether you're subtly controlling a stereo mix or pushing the circuit harder for additional character, the SA-2B is designed to make analog compression part of the sound — not merely a dynamics-management process.

Musical Optical Gain Reduction

Optical compression has earned its place in professional studios because of the naturally musical way it responds to dynamics.

The SA-2B takes that concept into a carefully matched stereo architecture using two custom optical gain-reduction elements.

Its attack and release controls provide continuously variable, fixed, or combined fixed/manual operation, allowing the compressor to move from smooth automatic-style control to more deliberate dynamic shaping.

That flexibility makes the SA-2B equally comfortable adding gentle cohesion to a mix bus or delivering more obvious compression when the production calls for it.

Built-In Parallel Compression

Want the density and harmonic character of heavier compression without losing the transient detail of the original signal?

Turn the Dry/Wet Blend control.

Parallel compression is built directly into the SA-2B, allowing you to blend the compressed and uncompressed signals without setting up additional routing in your console or DAW.

Push the compressor harder for tone and density, then blend the original signal back in until you find the ideal balance between punch, dynamics and analog character.

5-Position Sidechain High-Pass Filter

Low-frequency energy can make a stereo compressor work harder than you want it to. A powerful kick drum or bass note may trigger excessive gain reduction and cause the rest of the mix to pump.

The SA-2B addresses this with a 5-position sidechain high-pass filter.

By reducing the amount of low-frequency information reaching the compressor's detector circuit, you can maintain tighter, more consistent compression while allowing the low end to retain its impact.

It's an especially useful feature when processing mix buses, drum buses and bass-heavy productions.

True Bypass for Confident A/B Comparisons

The SA-2B includes a true bypass switch, making it easy to compare your processed signal against the original.

This is particularly useful when making subtle mix-bus or mastering decisions, where level, tone and dynamics changes need to be evaluated carefully.

Switch the processing in and out and hear exactly what the SA-2B is contributing to your sound.

30dB of Gain

With up to 30dB of gain, the SA-2B provides plenty of level capability for professional studio applications.

Combined with its transformer-coupled tube circuitry and optical gain-reduction architecture, the SA-2B gives engineers a powerful analog tool for controlling dynamics while simultaneously shaping tone.

Handmade Analog Craftsmanship

Every Stam Audio SA-2B is handmade in Chile.

Rather than treating the two channels as unrelated compressors sharing the same chassis, Stam Audio carefully auditions and matches critical components — including transformers, tubes, capacitors and optical elements — to create a stereo processor designed to behave cohesively across both channels.

For engineers building a serious analog mix or mastering chain, that attention to stereo matching can be just as important as the compressor circuit itself.

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Key Features

• Stereo tube optical compressor inspired by the legendary Danish 1B-style compression circuit

• Dual-channel original-style 1B circuit and schematic

• Proprietary channel-matching architecture designed for consistent stereo operation

• Custom laboratory-matched optical gain-reduction elements

• Custom US-made input transformers

• Swedish-made Lundahl output transformers

• Selected 12AU7 and 12AX7 tubes

• Up to 30dB of gain

• Continuously variable, fixed, or fixed/manual attack and release control

• Dry/Wet Blend control for onboard parallel compression

• 5-position sidechain high-pass filter

• True bypass for accurate A/B comparisons

• Designed to maintain stable stereo imaging during gain reduction

• Excellent for stereo mix bus, drum bus, subgroups and mastering

• Classic-style controls and knobs

• 20Hz–20kHz frequency response

• Greater than 95dB signal-to-noise ratio

• Heavy-duty 3U rackmount chassis

• Handmade in Chile

• 2-year manufacturer's warranty

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Technical Specifications

Specification	Details
Product Type	Stereo Tube Optical Compressor
Channels	2
Circuit	Original-style 1B circuit and schematic, dual channel
Compression Type	Optical / Tube
Gain Reduction Elements	2 custom matched optical GR elements
Input Transformers	2 custom US-made transformers
Output Transformers	2 custom Lundahl transformers
Tubes	Selected 12AU7 and 12AX7
Maximum Gain	30dB
Attack / Release	Continuously Variable, Fixed, or Fixed/Manual
Parallel Compression	Dry/Wet Blend Control
Sidechain Filter	5-position High-Pass Filter
Bypass	True Bypass
Frequency Response	20Hz–20kHz ±0.1dB
Signal-to-Noise Ratio	>95dB
Rack Size	3U
Manufacturing	Handmade in Chile
Warranty	2 Years

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Ideal Applications

The Stam Audio SA-2B Stereo Tube Opto Compressor is an outstanding choice for:

Stereo Mix Bus — Add controlled movement, analog depth and cohesion while maintaining a stable stereo image.

Mastering — Apply refined stereo dynamic control with premium tube and transformer coloration.

Drum Bus — Add weight and density while using the sidechain HPF to prevent kick energy from dominating the compressor.

Vocal Groups — Smooth stacked vocals and backing-vocal buses while adding tube richness.

Keys & Synths — Give digital instruments and stereo synthesizers additional analog dimension and dynamic control.

Acoustic Instruments — Smooth dynamic variations while retaining a natural, musical presentation.

Stem Processing — Add analog character and controlled dynamics to stereo instrument groups before the final mix.

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Why Choose the Stam Audio SA-2B?

Great stereo compression is about more than controlling peaks.

It is about making a mix move as one without collapsing the space between its elements.

The Stam Audio SA-2B combines the musical behavior of tube optical compression with matched stereo architecture, premium transformers, selected tubes and modern workflow features such as parallel compression, sidechain filtering and true bypass.

For producers, mixing engineers and mastering studios looking for a premium stereo tube opto compressor that combines vintage-inspired character with modern stereo functionality, the SA-2B deserves a place at the center of the analog rack.