Antelope Audio A4-1B Opto Valve Compressor

The A4-1B Analog Automated Opto-Valve Compressor is a high-performance audio device that masterfully blends classic analog warmth with cutting-edge digital precision. Designed for audio professionals seeking the rich, authentic sound of vintage Scandinavian tube compression, the A4-1B offers a fully analog signal path constructed with top-tier components. Custom transformers and premium tubes provide high-fidelity audio with tight low-end response, while its opto-cell detection system ensures precision in compression characteristics. The unit is equipped with advanced filters, including high-pass, band-pass, and de-esser modes, making it versatile for vocal, instrument, and sidechain applications.

Modern technology enhances its usability with DAW integration via the optional A4 software suite, enabling remote control, automation, and preset recall through VST3, AAX, or AU plugins. Proprietary motorized potentiometers and advanced digital control streamline adjustments for efficiency and consistency. Whether you're in a studio or live setting, the A4-1B delivers a seamless mix of vintage tone and contemporary functionality, ensuring it's a perfect fit for professional workflows.

• Captures the classic Scandinavian compression tone with a fully analog circuit.

• Premium tubes and custom transformers deliver high-fidelity, rich, and warm audio.

• Combines analog design with digital precision for seamless performance.

• Digital controls enable faster adjustments and ensure reliable, noise-free operation.

• Variable attack and release times for tailored compression.

• Sidechain filtering includes low-pass, high-pass, and band-pass options.

• De-esser mode ensures clean and precise vocal and instrument handling.

• DAW integration allows remote control, automation, and preset recall.

• Motorized knobs apply settings instantly to hardware.

• Includes a VU-meter for monitoring input, output, and compression levels.

• Automated calibration ensures consistent performance over time.

• Remote operation through plugins or a standalone app.

• Includes a free one-year membership with access to additional plugins and updates.

GENERAL SPECIFICATIONS:

• 100% analog audio circuit

• Custom-designed UK transformers

• High-quality tubes for sonic performance

• Pre-sorted opto-cell for compression precision

• All tube-based push-pull amplifier

• Continuously variable attack and release times

AUDIO FEATURES:

• Ratio: 2:1 to 10:1

• Threshold: off to -40 dBu

• Attack: 0.5 ms to 300 ms

• Release: 50 ms to 10 s

• Gain: off to +30 dB

• Maximum output level: +24 dBu

• Maximum input level: +24 dBu

• Noise level: < -80 dBu

• Input impedance: 10 kOhms differential

• Output impedance: <60 Ohm

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

AUTOMATION AND DIGITAL FEATURES:

• Remote control via VST3, AAX, AU plugin, or standalone app

• Proprietary motorized knobs for instant hardware settings

• Automation for attack, release, gain, threshold, and ratio via DAW plugin

• Comprehensive preset system for session recall and A/B testing

• Extended sidechain filtering: low pass, high pass, band pass filters

• De-esser mode with narrow band pass filter

POWER AND DESIGN:

• Modern power supply with automatic voltage adaptation (95 V-245 V, 50-60 Hz)

• DC heating for tubes to reduce noise and enhance warmth

• Consistent stereo-link performance via calibration system

• Operating temperature: 0-50C (32-122F)

METERING AND CALIBRATION:

• VU meter for input, compression, and output monitoring

• Multiple reference levels for precise metering

PHYSICAL DIMENSIONS AND WEIGHT:

• Device dimensions: 88 mm (H) x 483 mm (W) x 252 mm (D) / 3.47 in (H) x 18.98 in (W) x 9.92 in (D)

• Device weight: 4.4 kg (9.70 lbs)

• Box dimensions: 140 mm (H) x 640 mm (W) x 350 mm (D) / 5.51 in (H) x 25.20 in (W) x 13.78 in (D)

• Box weight: 6.5 kg (14.33 lbs)

IN-THE-BOX CONTENTS:

• A4-1B analog compressor

• Power cable

• USB-C to USB-C cable

• Get Started leaflet

ADDITIONAL FEATURES:

• Includes one year of Antelope Membership with Synergy Core Native plugins and updates

• Optional A4 software suite available via membership plan