B&K Reference 4430 Owner's Manual page 9

Five way binding posts are provided. One pair for each channel. They are designed to
accept a banana-type plug or spade lug connector (shown below) and are color coded
for easy identification. The red (+) post should always be connected to the speakers (+)
jack. The black (-) post should always be connected to the speakers (-) jack.
Here is a typical amplifier setup:
Unbalanced - RCA type connectors accept line input from the preamplifier's
unbalanced output connectors. There are three input connectors, one
for each channel, that may be used to connect the amplifier to the
preamplifier.
Spade connector Banana jack
RCA cable connector -
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