3
P = V
2
/ Z
Z = V
2
/ P
COLLEGAMENTI
CONNECTIONS
SPEAKER’S CONNECTION TO A CONSTANT
VOLTAGE SYSTEM
This connection system implies that each speaker is
equipped with its own line transformer. The ampliifer
shall be equipped with 100V / 70V constant voltage
outputs.
The loudspeakers connected in parallel to amplifier’s
output will make system expansion easier, if required, by
simply shunting from any of the previously installed
speakers. Similarly, the loudspeakers which are not
necessary anymore can be removed.
Matching the ‘phase’ is necessary both in the connection
of each speaker to its own transformer and in the
connection in parallel of the speakers.
All the constant voltage outputs (100V / 70V) of a single
amplifire can be connected at the same time, provided
that amplifier’s rated power remains equal or higher to
the sum of the power of all the speakers installed on
each output line.
Using the following formula: P = V /Z with V being 100V /
70V and Z being speaker’s transformer primary
impedance - any power applied to each speaker can be
calculated. If , instead, you know the voltage (100V /
70V) and the rated power (or powers) of the transformer
and you want to calculate transformer impedance, the
following formula applies: Z = V / P
2
2
SPEAKER’S CONNECTION TO A CONSTANT
IMPEDANCE
Constant impedance outputs are generally used in the
case of line with a small number of speakers having a
certain power and being placed at a minimum distance
from the amplifier.
Seakers connection will be a combination of connection
in parallel and series connection, so to bring
loudspeakers total impedance to a value which is not
critical for the amplifier. In the series connection the
positive lug shall be connected to the negative lug of the
following speaker.
In the connection with constant impedance it is always
recommended that speakers total power is higher than
the power supplied by the amplifier.
If in the connection with constant impedance the volume
of one or more speakers needed to be set independently
or also if any speaker needed to be switched off, the use
of attenuators keeping impedance constant is required.
In the series connection, whatever the impedance of
each speaker, the total impedance results from the sum
of all the impedances. Anyway, using sound speakers
with equal impedance and power is recommended.
