Klark Teknik 2A-KT Dynamic effect

Klark Teknik 2A-KT — Classic Optical Tube Compression in a Modern 2U Chassis

The Klark Teknik 2A-KT is a single-channel optical tube compressor and leveling amplifier inspired by the legendary Teletronix LA-2A from the early 1960s. At its core sits a vintage-style no-lag optical attenuator paired with hand-selected 12AX7, 12BH7, and EL84 tubes. This 2U rackmount unit delivers the soft, fat, big character of classic tube optical compression in a road-ready chassis.

Modern Capabilities Beyond the Vintage Original

Most vintage-style tube leveling amplifiers stop at the original feature set, but this model adds capabilities rarely found in its peers. The Pre-emphasis trim adjusts the sidechain's high-frequency response without affecting the main audio signal, while a Limit/Compress switch toggles between fixed compression and near-infinite limiting ratios. Two units link via the adjustable Stereo Link TRS connector for matched stereo bus compression.

Tube Signal Path — Warmth and Headroom

Inside the 2A-KT, the all-tube circuit delivers ultra-low-noise output with tight bass and airy treble.

• Tube Complement: 12AX7, 12BH7, EL84 — hand-selected gain and output tubes
• The lag-free electroluminescent optical attenuator acts as a vintage-style control element that eliminates the need for manual attack or release adjustments.
• Signal Path: fully discrete — components meet or exceed original LA-2A specifications

Dynamic Range and Frequency Response

Across the full audible spectrum, the 2A-KT stays transparent on any source.

• Frequency Response: 10 Hz – 20 kHz (±1 dB) — full-range, transparent across any source
• Gain Reduction: 0 – 30 dB (up to 40 dB) — wide dynamic control window
• Attack Time: 10 ms — ultra-fast attack catches transient peaks cleanly
• Release Time: 50 ms to 5 s — program-dependent release for natural envelope recovery

Connectivity, Metering, and Rack Form Factor

The rear panel houses transformer-balanced XLR and 6.35mm TRS I/O plus a stereo link connector.

• Inputs: XLR, 6.35 mm TRS (balanced) — transformer-balanced via Midas input transformer
• Outputs: XLR, 6.35 mm TRS (balanced) — transformer-balanced via Midas output transformer
• Format: 1 channel, 2U rackmount — single-channel unit
• Power Supply: autoranging universal switch-mode — worldwide compatibility
• Weight: 2.9 kg — manageable for portable rack setups