CSL Series Power Amplifiers
Page 8
eration, distortion and excessive heating.
2.3 Input Sensitivity Adjustment
The input sensitivity switch inside the amplifier is set to
0.775 volts at the factory. It can be changed to 1.4 volts
or a voltage gain of 26 dB as follows:
1. Turn off and unplug the amplifier from the AC source.
2. Remove the access cover on the back panel.
3. Locate the labeled access hole for the sensitivity switch.
4. Set the switch to the desired position.
5. Replace the access cover plate.
When set to 26 dB gain, the
460 CSL requires a 2.0 volt
input, the
800 CSL requires a 2.5 volt input and the 1400
CSL requires a 3.2 volt input to deliver full output into an
8 ohm load.
2.4 Additional Load Protection
Because
CSL amplifiers can generate enormous
power, it may be desirable to protect loudspeakers from
damage due to excessive power. A common way to do
this is to put a fuse in series with the load. This may be
accomplished with a single fuse to protect the entire
system, or by fusing each driver separately. Use Figure
2.4 to find the correct fuse.
Example: (A) Choose the peak music power for the loudspeaker
(such as 75 watts). (B) Find the loudspeaker impedance (8
ohms). (C) Draw a line between points A and B. The line inter-
sects the middle scale at the correct fuse value (1.5 amps).
Fig. 2.4 Loudspeaker Fuse Nomograph
1.0
1.2
1.4
1.6
2.5
3
4
5
6
7
8
9
10
12
14
16
20
25
30
20
15
10
8
6
5
4
3
2
1.5
1
.8
.6
.5
.4
.3
.2
.15
.1
.08
3000
2000
1500
1000
800
600
400
300
200
150
100
80
60
40
30
20
15
10
8
6
4
3
2
1.5
1
SPEAKER Z
(ohms)
FUSE
(amps)
SPEAKER RATING
PEAK MUSIC POWER
(watts)
(Typically 4 times the continuous average power)
Example: Z = 8 ohms.
Peak Power = 75 W
Answer: Fuse = 1.5 A
2
40