BSS Audio FDS-334T Owner's Manual User Manual
Page 11
1 1
FDS-336T Back Panel
AC Power Connections
The FDS-334T/336T will accept input AC from 100 - 240 Volts, 50-60 Hz. It does not have a
power switch and must be shut down by removing the power cord from the mains supply.
If the mains fuse should blow, replace only with a new fuse of correct size (20 mm) and rating
(T1A 250v).
WARNING: THIS DEVICE MUST BE EARTHED!
A 3-wire earthed outlet must always be used. The earth terminal of the IEC plug is required by
wiring codes and regulations. It must always be connected to the electrical installation safety
earth. The FDS-334T/336T has carefully designed internal earthing plus balanced Inputs and
Outputs to eliminate the possibility of earth loops (hum).
About earth loops
A typical example of an earth loop situation would be when two interconnected components of
a system are earthed through their individual AC power earth connections to separate AC power
outlets. In this case a path to ground exists both directly through the mains earth of each
component and also via the shield in the signal wire to the AC power earth connection of the
other component. In effect the two paths to earth form a loop antenna which picks up
interference currents from surrounding equipment. Because of lead resistance these induced
currents are transformed into voltage fluctuations in the grounding system and hence the
reference ground is no longer at a stable potential.
Various connection configurations can prevent ground loops occurring. The aim is always to
ensure that a loop path is never actually formed. The most flexible solution, and easiest to
implement in a touring system, is to use the practice of telescoping shields. This method is
highly effective in removing ground loops and prevents unwanted signals entering the signal
chain as the shield is always connected to ground at only one point.
The Minidrive is designed with the Input earth connections isolated so that an earth loop will
not occur between the FDS-334T/336T and the preceding source component. However, an
earthloop could occur between an Output connection from the Minidrive and an amplifier with
an input ground connection. In this situation the signal cable shield can be
disconnected at one end to prevent interference.
Rear Panel Connections