Niles SI-1260 Installation & Operation Manual page 26

Listening at Higher Volumes
An output of 60 watts is adequate power to completely drown out conversation in
a normal sized room. Even at those levels, the 51-1260 will sound clear and clean.
Obviously, it requires more power to achieve a reasonable volume of sound in a
large room than it does in a small room. Even if you are normally very careful, it is
possible to turn the volume so high that the amplifier runs out of power. This cre-
ates "clipping" distortion.
Clipping distortion makes treble sound very harsh and unmusical. If you hear harsh
sounding treble from any speakers, immediately turn down the level controls for
the channel pairs connected to those speakers. These harsh sounds include power-
ful high frequency sound spikes that will quickly damage the tweeter of any loud-
speaker.
If you continue to operate the amplifier at "clipping" power levels the protection
circuits will operate. The protection circuits will reset when output signal condi-
tions have returned to normal. Perpetually over-driving your speakers and amplifier
is abuse and will void the manufacturer's warranty on all affected products.
Cleaning and Maintenance
The internal parts of the 51-1260 are electronic and require no maintenance.
Once a year it is appropriate to twist each input RCA connector to remove any
oxidation and improve conductivity.
You can clean the amplifier with soft c'oth or a paper towel dampened with water.
DO NOT use any spray-type or abrasive cleaners on the amplifier.