Boulder Amplifiers Integrated Amplifier 865 - Manual (Page 11)

CONNECTING AN UNBALANCED SOURCE
Although the inputs are all of the 3-pin XLR type, an unbalanced
source is easily accommodated by using a special cable. This cable has
an RCA phono type connector on the source end and a 3-pin connector
(for an input) at the 865 Integrated Amplifier.
The negative input (Pin 3) should be wired to ground only at the
RCA phono connector. This brings the negative input reference of the
865 to the unbalanced source ground, thus reducing ground loops.
Another option for accommodating unbalanced sources is that of
the Boulder ABL2 input adapter. It converts a balanced XLR input into
a RCA connector input right at the rear of the 865. Please contact your
dealer for information regarding the ABL2 Input Adapter.
Like the above cable, the negative input of the 865 is connected to
the ground of the RCA connector. However, this negative side will then
share the shield wire with the chassis ground and will not have the best
hum rejection.
GETTING
STARTED
1-5
UNBALANCED INPUT CABLE
3-NEG INPUT
2-POS INPUT
1-GROUND