Warm Audio WA-2A Optical Tube Compressor

The Warm Audio WA-2A is an optical tube compressor based on the classic 2A design, known for its smooth and musical compression on vocals, bass, and acoustic instruments. The circuit operates at high voltage, is transformer-balanced, Class-A, and fully discrete, featuring American CineMag input and output transformers.

At the heart of the compression is a Kenetek opto module in a T4 enclosure, mounted in a socket so that other opto cells can also be used. The four tubes are also mounted in sockets for easy replacement. The pre-emphasis control determines how sensitively the compressor responds to high frequencies, and two units can be linked via TRS for stereo use. The meter displays either gain reduction or output level.

Specifications:

• Brand: Warm Audio
• Item number: WA2A
• Type: optical tube compressor, 1 channel
• Opto cell: Kenetek T4-style module (replaceable)
• Tubes: 2x 12AX7, 1x 12BH7, 1x 6AQ5 (or 6P1J)
• Transformers: CineMag USA input and output
• Controls: gain, peak reduction, variable pre-emphasis
• Stereo link via TRS
• Connections: balanced XLR and TRS inputs and outputs, 600 ohms
• Frequency range: 15 Hz - 20 kHz (±1 dB)
• Gain: 40 dB, attack: 10 ms
• Release: 0.06 s to 50%, 0.5 - 5 s full
• Maximum input: +16 dB
• Power supply: 115/230 V switchable
• Format: 2U 19-inch rack