Unika SDI-1, User Manual

UNiKA SDI-1

User Guide

5

ELIMINATING HUM AND BUZZ AND THE GROUND LOOP

The SDI-1 is equipped with output isolation transformers to eliminate hum and 
buzz caused by stray DC voltage and ground loops.

Computers, CD players and other consumer equipment can be noisy 

-

 this 

is particularly true when incorporating audio with a projector - so isolation 
transformers can be very useful when combating system noise.

The Ground Lift switch on the output takes this one step further by lifting pin-
1 on the XLR. Computers are often the source for noise problems in audio 
systems, so greater care is certainly needed to keep things quiet.

INPUT PAD ATTENUATION

The most common use of the direct input is with guitar pick-ups, keyboards 
or audio devices like CD players, computers etc. The optimal setting for this 
is most likely with the pad switch set to 0dB, although with some high-output 
pick-ups the performance of the direct input may be improved if the pad 
switch is set to -20dB to prevent possible clipping of the input signal.

The instrument is connected to the XLR-¼“Combo jack socket using a TS 
jack plug, and a parallel link feed taken from the LINK TS jack socket to the 

instrument amplifier.

The direct input can also be fed either from a line-level output from the head-
amp (pad set to -20dB) or from the head-amp speaker output (pad set to 
-40dB).