12
Nagra -
Pyramid Monoblock Amplifier
Security
When you deal with high power amplifiers, it is very important to
implement security features. These features enhance the lifetime of the
amplifier as well as protect the loudspeakers*. This will allow you to
play music without bothering about security; it is already handled by
the amplifier itself.
Protection mode
Whenever one of the following events happen (described below):
-
clipping
-
shortcut
-
DC problem
the Pyramid will go into the
Protection Mode
.
The
ERROR
LED will light up, the Pyramid
will no longer play.
To turn the Pyramid ON again, you have
to turn it OFF (
O
) and ON (
I
) using the
Main Switch (1) as described in page 10.
Clipping protection
Clipping will occur when you push the pyramid to its limit, the front red
LED will start to blink. While a short “clip” will not even be heard, a
long clip can damage the amplifier or the loudspeakers*. That’s why,
after one second of continuous clipping, the PMA will self-protect by
going into the
Protection Mode
.
Short-circuit protection
In the event of a short-circuit on the speaker’s connectors, the front
red LED will light up; after 1S, the amplifier will go into the
Protection
Mode
. Before turning the unit ON again, you should check the speaker
connections (refer to page 7).
DC protection
A DC (direct current) component generated from the amplifier could
damage your loudspeakers. If a DC component of more than +/- 2.5 V
appears on the output of the Pyramid, it will go into
Protection Mode
.
Tip
If the Pyramid keeps going into the
Protection Mode
for no
obvious reason; please contact your Nagra dealer.
* if the loudspeakers can handle the PMA power
