Tube Optical Leveling Amplifier with Discrete Signal Path, 10Hz-20kHz Frequency Response, Midas Transformers, Pre-emphasis Trim, and Vintage-style VU Metering
 
Klark Teknik 2A-KT Tube Optical Compressor Features:
Classic tube compressor/leveling amplifier
Completely discrete signal path
Premium selection of 12AX7, 12BH7, and EL84 tubes
Lag-free optical attenuator based on vintage electroluminescent technology
Custom-built Midas input and output transformers
Frequency response: 10Hz–20kHz, ±1dB
Gain limiting: 0dB–30dB
Ultra-fast attack time: 10ms
Release time: 50ms to 5 seconds
Adjustable stereo-link connection
Variable Pre-emphasis for digital audio recording and broadcasting transmission
Vintage-style meter displays gain reduction and output
Transformer-balanced inputs and outputs on Neutrik XLR connectors
Rugged 2U rackmount chassis for durability in portable applications
Autoranging universal switch-mode power supply
Designed and engineered in the UK
 
Classic Optical Compression for a Song
Inspired by the mother of all optical compressors, Klark Teknik set the bar high for its 2A-KT Leveling Amplifier. With its warm, musical sound and flexible, highly effective dynamics control, the 2A-KT is eminently useful in live settings and in all stages of the recording process, from tracking to mixing to mastering. The beating heart of the 2A-KT is a vintage-style no-lag optical attenuator based on the same electroluminescent technology employed in its 1960s predecessor. The 2A-KT is built using high-quality discrete components — all of which meet or exceed the specifications of the legendary compressor it is based on. Its characteristic warmth comes courtesy of hand-selected premium 12AX7, 12BH7, and EL84 tubes in a circuit that delivers ultra-low-noise output with tight bass, liquid midrange, and delicate, airy treble.
 
The 2A-KT control set
Simplicity incarnate, the 2A-KT control set includes a Pre-emphasis trim that adjusts the sidechain that the compressor responds to without affecting the main audio signal. When cranked fully clockwise, the sidechain responds to the full frequency bandwidth of the incoming audio. As you turn the trimpot counterclockwise, the compressor responds less to the signal's high-frequency transients. The Peak Reduction knob controls the threshold of the compressor/limiter, with a maximum 40dB of gain reduction on tap. The Output Gain knob provides any makeup gain required for optimal output level.
 
Metering and I/O
Back in the 1960s and '70s, old-school VU meters ruled the roost, so Klark Teknik pays homage to the original with a classic d'Arsonval movement VU meter that averages short-duration signal peaks and troughs, providing a realistic visual indicator of perceived loudness. The Meter selection knob lets you display either gain reduction or output level. The 2A-KT features XLR and 1/4-inch TRS balanced line-level inputs and outputs with custom-designed Midas transformers. Unbalanced connections are obtained by inserting 1/4" TS cables.