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CONNECTING THE SPEAKERS
7. Selecting Speakers and Transformers Using
the Graph
When speakers are connected to the high impedance ter-
minal, the following three factors are concerned:
(1) Speaker wattage (P}
(2) Speaker transformer impedance (2)
(3) Number of speakers (n)
These factors are in the following relationship:
In the case of the 30 W amplifier:
_ (70.7 . W
pases
n
{70.7}?
_ 5000
2230
N30
In the case of the 100 W amplifier:
p = (70.7? < W
Zz
n
(70.7)?
— 3000
30 *" = "700
According to the graph, Z is calculated from W and n.
z>
68
Reading the Graph
Fig-1 and Fig-2 are graphs showing the relationship of W,
Z, and n for 30 W and 100 W, respectively.
{1) if the speaker wattage is known
z
a
The n and Z values are read based on the W value.
For example, if W = 2 W,
n=
15
Z = 2500.
That means, a maximum 15 units of 2 W speakers can be
connected,
The transformer impedance must be 2500 Q or more.
{2} If the number of speakers is known
2
Pp
The W and Z values are read based on the n value.
For example, ifn = 15,
W=2
Z = 2500,
Therefore, when 15 speakers are connected, each speak-
er should have 2 W and the transformer impedance must
be 2500 @ or more.
Connect speakers with an impedance of at least 2W as a
safety precaution.
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