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Klark Teknik KT-2A Optical Compressor




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Optical Compressor

Classic Optical Compression for a Song

Inspired by the mother of all optical compressors, Klark Teknik set the bar high for its KT-2A Leveling Amplifier. With its warm, musical sound and flexible, highly effective dynamics control, the KT-2A 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 KT-2A is a vintage-style no-lag optical attenuator based on the same electroluminescent technology employed in its 1960s predecessor. The KT-2A 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.


Impressive capabilities

The KT-2A boasts a truly impressive frequency response of 10Hz to 20kHz (±1dB), and it boasts capabilities you won't find in most vintage-style tube leveling amplifiers, such as gain limiting from 0dB to 30dB with an ultra-fast 10ms attack time, release times that range from 50ms to five seconds, and much more. The KT-2A's Limit/Compress switch lets you select between the internally fixed compression ratio of Compress mode and the near-infinite ratio of Limit mode. The adjustable Stereo Link TRS connector lets you gang a pair of KT-2As to blend their sidechain signals with shared threshold response.


The KT-2A control set

Simplicity incarnate, the KT-2A 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 KT-2A features XLR and 1/4" TRS balanced line-level inputs and outputs with custom-designed Midas transformers. Unbalanced connections are obtained by inserting 1/4" TS cables.


A new chapter in dynamics processing

While the book on compression/limiting may have been written in the 1960s, Klark Teknik adds a new chapter with their KT-2A. No slavish clone of the original, it brings new state-of-the-art capabilities to the party — and does so at a budget-friendly price that makes vintage-style tube optical compression available to a wider audience. It's fabulous on vocals, guitars, pianos, bass, drums — you name it. Today's digital recordings can sound cold, clinical, or harsh if proper attention is not paid to every component in the signal path — which makes the warm, smooth sound of tube optical compression a necessity. That's why Sweetwater recommends that no serious studio be without at least one high-quality tube compressor. And given the KT-2A's outstanding performance and value, you can put a pair of them in your rack, opening up even more possibilities.


Klark Teknik KT-2A 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
Klark Teknik 10-year warranty

Designed and engineered in the UK


Tech Specs

Type: Tube/Optical 
Number of Channels: 1 
Controls: Limit/Compress, Output Gain, Peak Reduction, Gain Reduction 
Frequency Response: 10Hz-20kHz 
Inputs: 1 x XLR, 1 x 1/4" 
Outputs: 1 x XLR, 1 x 1/4" 
Other I/O: 1 x 1/4" (stereo linking) 
Tubes: 2 x 12AX7, 1 x 12BH7, 1 x EL84 
Rack Spaces: 2U 
Power Source: Standard IEC AC connector 
Height: 3.5" 
Depth: 6.2" 
Width: 19" 
Weight: 6.4 lbs. 
Manufacturer Part Number: KT2A
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