Lowell manufacturing company, Speaker system connections – Lowell MA30 User Manual
Page 6
Instruction Sheet
IS-MA30
Issued: 9-10-14
Lowell Manufacturing Company
100 Integram Drive
Pacific, Missouri 63069 U.S.A.
Call: 800-325-9660
Fax: 636-257-6606
Click: www.lowellmfg.com
6
Result:
One speaker
receives the
total amplifier power.
AMPLIFIER
OUTPUT
8
W
4W
70V
25V
COM
One 8
W Speaker
SPEAKER
+
_
8
W
Result:
Each speaker
receives ½ of the
total amplifier power.
Two 8
W Speakers
wired in Parallel
AMPLIFIER
OUTPUT
8
W
4W
70V
25V
COM
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
AMPLIFIER
OUTPUT
8
W
4W
70V
25V
COM
Result: Each speaker
receives ¼ of the
total amplifier power.
Four 8
W Speakers
wired in Series/Parallel
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
AMPLIFIER
OUTPUT
8
W
4W
70V
25V
COM
Result: Total amplifier power is reduced due to
impedance mismatch. Each speaker receives
1/3 of the reduced total amplifier power.
Three 8
W Speakers wired in Series
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
Speaker System Connections
The amplifier includes a speaker output screw terminal
strip.
Connect the speaker line common to “COM” and
the hot side to the 70V, 25V, 8
W, or 4W terminals.
70V
25V
8
W
4W
COM
Never connect an 8
W or 4W speaker system (that has no 70V or 25V matching transformers) to the 70V or 25V outputs.
8 Ohm Series/Parallel Speaker System Wiring
Lowell amplifiers include 8
W and 4W outputs that can drive basic 8W speakers without the use of any line matching
transformers. The impedance of the speaker load must always be equal to or greater than the impedance of the
amplifier output. For example, it is safe for the amplifier if the 8
W output is used to drive an 8W load or a 16W load,
and it is safe for the 4
W output to drive a 4W load or a 6W load, but it is not safe for the 8W output to drive a 6W load
and it is not safe for the 4
W output to drive a 2W load. Overloading the amplifier output can cause distortion and can
damage the amplifier and void the manufacturer’s warranty. It is also important to pay attention to the power rating
of the speakers used. If an 8
W speaker is fed from the 8W output of an amplifier and the amplifier is turned all the
way up, the speaker will receive the maximum power output of the amplifier. A speaker must be chosen with
sufficient power handling capacity for the amplifier used. For example, if an 8
W speaker can handle 150 watts and
it will be fed from the 8
W output of the amplifier, an amplifier with a power output of 150 watts or less should be
chosen so that if the amplifier is turned all the way up,
the speaker will be able to handle the amplifier’s full power
output. All of the Series/Parallel configurations shown below will result in load impedances that will be safe for the
amplifier when connected as shown. Depending on the size of the amplifier used, verify that the maximum amplifier
power when divided between the speakers, will not exceed the power rating of the speaker chosen .
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
SPEAKER
+
_
8
W
AMPLIFIER
OUTPUT
8
W
4W
70V
25V
COM
Result:
Each speaker
receives
1
/
8
of the
total amplifier power.
Eight 8
W Speakers
wired in
Series/Parallel