Mesa/Boogie pmn Stereo Amplifier User Manual


 
PAGE 18
SPEAKER IMPEDANCE MATCHING & HOOK-UP GUIDE: (Continued)
PARALLEL:
When wiring in parallel, the resistance of the speakers decreases. Two 8 ohm speakers wired in ( hooked-up )
Parallel results in a 4 ohm load. It’s easy to calculate the effect of a resistive load when all the speakers are all the same resistance.
It is really not suggested to wire different resistive load values in Parallel ( 8 and 4, 16 and 8 etc. ) The formula for fi guring the total
impedance in Parallel is the multiplication of the two loads divided by the sum of the two loads - i.e. putting two 8 ohm speakers in
Parallel results in a 4 ohm load. Connect the Positive side of Speaker A to the Positive side of Speaker B - Connect the Negative
side of Speaker A to the Negative side of Speaker B.
COMBINATION OF SERIES & PARALLEL:
This is really just two sets of Series wired speakers connected in Parallel. This is
how you maintain a consistent load with multiple speakers. The importance of this is more evident when you have more than one
cabinet to connect to your amplifi er. This is when you
need to fi gure out the loads and how to wire them up
without applying too low of a resistance on the amplifi er.
Simply connect the Positive side of Speaker A to the
Positive side of Speaker C.
Connect the Negative side of Speaker A to the Positive
side of Speaker B. Next, connect the Negative side of
Speaker C to the Positive side of Speaker D.
And lastly, connect the Negative side of Speaker B to the
Negative side of Speaker D.
4 Eight ( 8 ) Ohm speakers wired in Series Parallel = a
Total Load of 8 Ohms.
POSITIVE
Speaker
A
8 Ohms
Speaker
B
8 Ohms
NEGATIVE
Total Load = 4 Ohms
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
SPEAKER A
SPEAKER B
SPEAKER C
SPEAKER
D
NEGATIVE
All 4 Spkrs. are 8 Ohms
POSITIVE
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W
B
L
A
C
K
S
H
A
D
O
W