Klark Teknik has released the DN100 (singel channel) and DN200 (two-channel) Active DI Boxed with Extended Dynamic Range.
Claiming a ‘significantly higher clipping point than many other active DI Boxes’ the DI boxes deliver +10dBu output into a 2kΩ load – increased headroom means that higher level input signals can be accommodated without the need for an attenuating pad. Combined with a very low noise input circuit topology, they offer a very wide dynamic range, and only requires a single -30dB pad for use when connecting directly to instrument amplifier outputs.
‘Not only was the choice of the audio transformer particularly important in achieving this goal, but the impedances of the surrounding components were also highly critical in getting the best possible performance out of the audio transformer,’ the company says. ‘The line-driving characteristics of the transformer output were carefully optimised to provide the best frequency and phase responses for short and long cables and widely differing line and termination impedances.’
Care was taken to avoid audio transformer core saturation, and a fixed high-pass filter has been included in the signal path to roll off frequencies below those that are musically important. The lowest note on a five- or six-string bass guitar is B0 with a frequency of 30.87Hz, and the lowest note on an 88-key piano keyboard is A0 with a frequency of 27.50Hz. Both DIs maintain a frequency response of ±0.5dB at these lowest musical notes.
As well as the transformer in the signal path, the units have a transformer to isolate the power rails to the input circuit from the phantom power supply sourced from the output XLR connector. When used in conjunction with the Earth Lift switch, this full galvanic isolation of input and output interfaces ensures that any risk of earth loops is avoided when taking a direct feed from stage backline equipment.
A custom instrumentation-grade input circuit was designed to offer the very high input impedance required by passive guitar and bass pickups, while keeping the actual component values low to minimise noise.
Where the DN100 features one parallel-connected XLR and two quarter-inch TRS inputs, the DN 200 features dual parallel-connected combo TRS inputs, one that may also be used a link output for connection to a guitar or bass amplifier. When connecting to the XLR input only, the input impedance is 20kΩ, for line level equipment and offering even lower noise performance. This input impedance is too low for guitar and bass pickups and is removed from the circuit when a jack plug is inserted into a quarter-inch TRS input, resulting in a nominal 1MΩ input impedance for passive electric pickups.
The DN200 is also equipped with a Stereo input mini jack for connecting MP3 players or mobiles phones.
The untis are built to handle the rigours of life on the road, a thick aluminium extrusion protects the electronics, and covered by a tough silicone rubber sleeve.
More: www.klarkteknik.com
