User Manual

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Product Information Document
Active DI Box with Extended
Dynamic Range
DI Boxes
DN100
Balanced transformer-isolated output
Exhaustive listening tests using a wide variety of active and passive bass guitars, electro-acoustic
guitars and electronic musical instruments were carried out to select the components for DN100
to achieve the best musical sound. 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 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 di ering line and termination impedances.
Care was taken in the design of the DN100 to avoid audio transformer core saturation and a  xed high
pass  lter has been included in the signal path to roll o frequencies below those that are musically
important. The lowest note on a 5- or 6-string bass guitar is B0 with a frequency of 30.87Hz, and the
lowest note on an 88-key piano keyboard is A0 with a frequency of 27.50 Hz. DN100 still maintains a
frequency response of ±0.5 dB at these lowest musical notes.
As well as the transformer in the signal path, DN100 also has 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.
Dual-Impedance Inputs
A custom instrumentation-grade input circuit was designed for the DN100 using advanced
analogue design techniques to create the very high input impedance required by passive guitar and
bass pickups, whilst keeping the actual component values low to minimise noise. This innovative
approach to circuit design produces a very low noise  oor, which combined with the high clipping
point creates an unrivalled dynamic range in a +48 V phantom powered DI Box.
DN100 features one parallel-connected XLR and two ¼ " TRS inputs, one which may also be used a link
output for connection to a guitar or bass ampli er. When connecting to the XLR input only, theinput
impedance is 20 kΩ, ideal for line level equipment and o ering even lower noise performance.
Thisinput impedance is far too low for guitar and bass pickups and is removed from the circuit when
a jack plug is inserted into a ¼ " TRS input, resulting in a nominal 1 MΩ input impedance, ideal for
passive electric pickups.