Radial Engineering JDI, Руководство пользователя

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130 kΩ 98%
2%
Amp
Mixing Console
Radial Engineering Ltd. JDI Stereo™ Direct Box User Guide
6
UNDERSTANDING LOADING
A problem that was detected early on was the sound or effect that a transformer can impose on an instrument. Back in the early
days of direct boxes, 600Ω broadcast or telephone transformers were used. These had such a low impedance that almost half
of the signal from the instrument would be sent to the mixing desk, leaving very little left for the musician’s amp on stage. Pas-
sive basses would sound listless and have no punch. Active D.I. boxes solved the problem by increasing the input impedance
and buffering (amplifying) the signal to drive it.
The JDI’s input impedance is 130,000Ω – quite different from the old 600Ω days. This means that the JDI will not load down the
pickup, which in turn means that the THRU output going to the stage amp will sound just fine.
600 Ω 50%
50%
Amp
Mixing Console
600 Ω