Antelope Audio A4-1B Analog Automated Opto Valve Compressor - Complete

The Antelope Audio A4-1B is a groundbreaking analog hardware compressor that seamlessly merges vintage opto-tube warmth with cutting-edge digital control, giving audio professionals the best of both worlds in a complete, fully integrated system. Engineered to preserve the smooth, musical compression characteristics of legendary optical-tube units, the A4-1B elevates analog gear with modern-day workflow features that redefine studio flexibility.

At its core, the A4-1B features a hand-built, all-analog signal path, including custom UK-made transformers, hand-selected vacuum tubes, and a meticulously accurate circuit topology based on the iconic Danish opto design. This results in an unmistakably rich, warm tone that adds depth and character to vocals, bass, keys, and drums - with transparency and musicality even at high compression ratios.

Where the A4-1B truly breaks new ground is in its full digital integration. Through its dedicated VST3, AU, and AAX plugin, users gain precise remote control, DAW automation, instant preset recall, and even real-time motorized potentiometer movements that mirror plugin adjustments physically on the hardware. Features like sidechain filtering, de-essing, and A/B comparison are seamlessly built into the plugin, giving producers surgical precision in any modern production scenario.

• Authentic Opto-Tube Compression: 100% analog signal path with hand-picked tubes and custom UK-made transformers for warm, musical dynamics.

• Complete Plugin Integration: Includes perpetual license for the A4-1B plugin (VST3, AU, AAX) with full control of hardware parameters inside your DAW.

• Motorized Controls with Automation: Proprietary motorized potentiometers instantly respond to DAW automation and plugin adjustments.

• Instant Preset Recall & A/B Switching: Save unlimited presets in your DAW and switch between settings for fast comparisons and consistent recall.

• Advanced Sidechain Filtering & De-Essing: Built-in plugin filters (HP, LP, BP) for precise frequency control; includes vocal de-essing mode.

• Automatic Calibration System: Built-in self-calibration maintains compression accuracy and stereo consistency over time.

• Selectable Compression Modes: Choose from fixed, manual, or hybrid timing for flexible response to vocals, bass, keys, and more.

• Multiple Reference Levels: Selectable metering references (-10 dBu, 0 dBu, +4 dBu, +20 dBu) and VU monitoring for optimal alignment.

• High-Performance Specs: +24 dBu input/output headroom, < -80 dBu noise floor, and wide 20 Hz " 20 kHz +/- 1 dB response.

• Modern Power Supply: Auto-switching PSU with DC tube heating for lower hum, smoother startup, and global voltage compatibility.

GENERAL SPECIFICATION:

• 100 percent analog signal path

• All tube-based push-pull amplifier circuit

• Pre-sorted opto-cell for precision compression

• Custom UK-made input and output transformers

• Premium hand-selected vacuum tubes

• High-quality components throughout

• Frequency response: 20 Hz to 20 kHz ±1 dB

• Input impedance: 10 kOhm differential

• Output impedance: less than 60 Ohm

• Maximum input level: +24 dBu

• Maximum output level: +24 dBu

• Noise level: less than -80 dBu

COMPRESSION PARAMETERS:

• Continuously variable ratio: 2 to 10

• Threshold range: off to -40 dBu

• Attack time: 0.5 ms to 300 ms

• Release time: 50 ms to 10 s

• Gain range: off to +30 dB

• Modes: fixed, manual, hybrid

MONITORING & CALIBRATION:

• VU-meter modes: input, output, gain reduction

• Reference level selection: -10 dBu, 0 dBu, +4 dBu, +20 dBu

• Built-in opto-cell test and calibration system

• Calibration support for stereo-linked operation

DAW CONTROL & AUTOMATION:

• Motorized potentiometers for remote control

• Full plugin control via VST3, AU, AAX

• Real-time synchronization with hardware unit

• Plugin automation of attack, release, gain, threshold, ratio

• Preset management system with A/B comparison

• Plugin recall inside DAW projects

• Extended filtering: high-pass, low-pass, band-pass

• De-essing with narrow band-pass side-chain filter

POWER & ENVIRONMENTAL:

• Power: 95 V to 245 V, 50/60 Hz

• Modern PSU with automatic voltage adaptation

• Operating temperature: 0 to 50 C

PHYSICAL SPECIFICATIONS:

• Unit dimensions (H x W x D): 88 x 483 x 252 mm

• Unit weight: 4.4 kg

• Box dimensions (H x W x D): 140 x 640 x 350 mm

• Shipping weight: 6.5 kg

INCLUDED IN COMPLETE VERSION:

• A4-1B analog compressor

• Power cable

• USB-C to USB-C cable

• Get Started leaflet

• A4-1B Plugin Perpetual License leaflet (Complete edition)