Tascam PA-30 - Manual (Page 8)

Output Connections
Each channel of the PA-30 will drive a minimum load
impedance of 8 ohms. Connecting a load of lower
impedance will result in current limiting and may
trigger the Protection circuits to shut down the
amplifier.
Figure 7 shows a normal stereo-mode connection of
two individual speakers to the PA-30 outputs. When
making loudspeaker connections, always be sure to
maintain correct polarity; if you wire the speakers out
of phase with one another, you will get acoustical phase
cancellations.
There are two basic methods for connecting multiple
speakers to a single amplifier output: series connection
and parallel connection. Loudspeakers connected in
series present a higher net impedance than any single
unit alone. Parallel connection, by contrast, lowers the
net load impedance. Sometimes, the two methods are combined to obtain an optimum load impedance.
Figure 8 shows what happens to the net load impedance
when multiple loudspeakers are connected in various
ways. (In all cases, it is assumed that all speakers in a
given system have the same impedance.)
Generally, only parallel connection is used in
professional audio, for two fundamental reasons. First,
if one of the speakers in a parallel system fails, the
others will still function. (Remember those old
Christmas lights that all went out the minute one bulb
failed? They were connected in series.) Second, parallel
connection results in a lower net impedance. The closer
the load impedance gets to the allowable minimum for
the amplifier, the more efficiently is the amplifier's
power capability used, since the lower load impedance
draws more current from the output stage.
8
TASCAM PA-30
Connection and Installation
Figure 7. Typical Stereo Output Connection
Figure 8. Connecting Multiple Loudspeakers
Each Unit
4 OHMS
8 OHMS
16 OHMS
Two In Series
8 OHMS
16 OHMS
32 OHMS
Three In Series
12 OHMS
24 OHMS
48 OHMS
Four In Series
16 OHMS
32 OHMS
64 OHMS
Each Unit
4 OHMS
8 OHMS
16 OHMS
Note: Impedances shown in brackets are
too low for the amplifier. Do not use three
loudspeaker configurations.
Two In Parallel
(2 OHMS)
(4 OHMS)
8 OHMS
Three In Parallel
(1.33 OHMS)
(2.66 OHMS)
(5.33 OHMS)
Four In Parallel
(1 OHM)
(2 OHMS)
(4 OHMS)
Four In Series/Parallel
(4 OHMS)
8 OHMS
16 OHMS
120V