Classe Audio CA-M400 Owner's Manual page 23

Make sure all the connections are snug and cannot be easily
wiggled free, but do not overtighten them. If you can give the
speaker wires a reasonable tug without movement, they are snug.
Further tightening will not make a better connection, and (taken
to the extreme) may damage the connectors.
6 Double-check all your connections.
We understand that this step sounds redundant, but it is worth the
extra minute or two it might take just to ensure that all connec-
tions are correct and secure.
7 Turn on all the other components in your system, and then
turn on your amplifier.
It is always good practice to turn any power amplifier on last, and
to turn it off first. Doing so prevents any turn-on/turn-off tran-
sients that might originate in other components from damaging
your loudspeakers.
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