HHB Circle 5 Operating Instructions Manual page 4

Circle 5 Active
Audio connection to the active Circle 5 is via a balanced XLR
or unbalanced RCA phono. The audio should be connected
to either input, not both, with the input switch being set
accordingly - pushed in for balanced XLR and out for
unbalanced RCA phono. Power should be switched off when
connecting or disconnecting any signal to or from the
loudspeakers, or when changing the position of the selector
switch, since the loudspeakers and internal amplifiers may
be damaged.
The active Circle 5 should be connected to a suitable mains
power supply using the mains cable supplied. The mains
input is via an IEC connector.
The XLR input is wired as a differential input, as shown
below, (viewed from the end of the male pins). Some older
American pieces of equipment reverse the functions of pins
2 and 3, effectively phase reversing the signals.
Pin Connection
1 Ground
2 Live (Hot)
3 Return (Cold)
When cable runs are long - about ten metres or more
(approximately thirty feet) - or there is electromagnetic
interference in the vicinity of the cable (from a motor, for
instance), it is advisable to use balanced XLR cables so as
to avoid any induced noise.
4
3
2 1