
SS75.4 / SS125.4 / 4 CHANNEL AMPLIFIER APPLICATIONS
4 CHANNEL FULL RANGE SYSTEM
Here we show how to use the 4 channel amplifiers as straight forward discrete 4 channel full range units.
Interconnect cable checklist:
- Connect the four inputs of the amplifier to a Radio/CD with quality RCA cables.
Switch setting checklist: - 1/2CH 
Crossover frequency control checklist:
Channels 1/2:
- HI PASS: N/A
- LOW PASS: N/A
Level control checklist:
-Refer to the section “Setting up systems after installation for best performance”
Minimum final loudspeaker impedances: - 
FULL RANGE
SPEAKERS
Channels 3/4:
-HI PASS: N/A
-LOW PASS: N/A
FULL RANGE
STEREO LINE
INPUTS
| 
 | CH3/4 | L | 
 | 
 | 
 | 
 | 
| 
 | 
 | 
 | 
 | LINE | 
 | |
| 
 | CH1/2 | 
 | 
 | 
 | INPUT | 
 | 
| 
 | CH1 2 | + - gnd + | HI INP | + | CH3 CH4 | 
 | 
| 
 | 5V 0.2V | LEVEL | 5V 0.2V | 
 | LEVEL | 
 | 
| CHANNEL 1 / 2 | 0dB 12dB 60Hz 1.2KHz | BASS EQ HPF | 0dB 12dB 60Hz 1.2KHz | 
 | BASS EQ HPF | CHANNEL 3 / 4 | 
| 
 | 30Hz 250Hz | LPF | 30Hz 250Hz | 
 | LPF | 
 | 
| 
 | FULL LPF HPF | FULL LPF HPF | 
 | 
 | ||
| 
 | LINE | 
 | CHANNEL | 2 3 4 | MODE | 
 | 
| 
 | OUTPUT | 
 | 
 | 
 | 
 | 
 | 
| 
 | OUTPUT | LEFT | 
 | 
| 
 | 3/4 SPEAKER | IGHT | B IDGE | 
| 
 | CH | - | 
 | 
| FUSE | 
 | 
 | TO BATTERY + 12 Volts VIA FUSE | 
| POWERINPUT | REMGND+12V | 
 | |
| 
 | REMOTE  | ||
| 
 | 
 | 
 | |
| 
 | 
 | 
 | CHASSIS GROUND | 
| 
 | OUTPUT | LEFT | 
 | 
| 
 | CH ½ SPEAKER | +RIGHT | B IDGE | 
| 
 | 
 | POWER PROTECT | 
 | 
2 or 3 CHANNEL FULL RANGE SYSTEM
Here we show how to use the 4 channel amplifiers as full range 2 or 3 channel units by taking advantage of the mono bridging capability of all Autotek amplifiers.
The following example shows how to create a 3 channel system by mono bridging channel pair 3 / 4. In order to create a 2 channel system, simply follow the example to also mono bridge channel pair 1 / 2.
Interconnect cable checklist:
-Connect the inputs of channel pair 1/2 to a suitable stereo source, e.g. a head unit with good quality RCA cables.
-A MONO signal source is required to bridge channel pair 3/4, such as would be available from the mono sub bass output of an active crossover, whether standalone, or built into a head unit or equalizer.
Important: Do not be tempted to connect the hot, or positive outputs, from any source together to obtain a mono signal, as this could very well damage the output stage of that source.
-It is necessary to feed the SAME signal to both left and right inputs via a Y- adapter RCA cable.
-Connect the mono speaker positive terminal to the LEFT +, and its negative terminal to RIGHT - as shown.
Switch setting checklist:
-1/2CH 
-3/4CH 
Crossover frequency control checklist:
Channels 1/2:
-HI PASS: N/A
-LOW PASS: N/A
Channels 3/4:
-HI PASS: N/A
-LOW PASS: N/A
TIP: If you are using the mono sub bass output of an active crossover, there is nothing wrong with switching in the low pass filter in these amplifiers for a steeper low pass rolloff.
Level control checklist:
-Refer to the section “Setting up systems after installation for best performance”
Minimum final loudspeaker impedances:
-
-
| MONO | 
 | 
| OR SUB BASS | STEREO | 
| SPEAKER | 
FULL RANGE
1STEREO
1MONO FULL RANGE LINE INPUTS
| 
 | CH3/4 | L | 
 | 
 | 
 | 
 | 
| 
 | 
 | 
 | 
 | LINE | 
 | |
| 
 | CH1/2 | 
 | 
 | 
 | INPUT | 
 | 
| 
 | C CH2 | + gnd - + | I INPUT | + gnd - + | CH3 CH4 | 
 | 
| 
 | 5V 0.2V | LEVEL | 5V 0.2V | 
 | LEVEL | 
 | 
| CHANNEL 1 / 2 | 0dB 12dB 60Hz 1.2KHz | BASS EQ HPF | 0dB 12dB 60Hz 1.2KHz | 
 | BASS EQ HPF | CHANNEL 3 / 4 | 
| 
 | 30Hz 250Hz | LPF | 30Hz 250Hz | 
 | LPF | 
 | 
| 
 | FULL LPF HPF | FULL LPF HPF | 
 | 
 | ||
| 
 | LINE | 
 | CHANNEL | 2 3 4 | MODE | 
 | 
| 
 | OUTPUT | 
 | 
 | 
 | 
 | 
 | 
| 
 | OUTPUT | +LEFT | 
| 
 | CH 3/4 SPEAKER | |
| FUSE | 
 | 
 | 
| POWER INPUT | GND REM +12V | 
 | 
| 
 | OUTPUT | |
| 
 | CH ½ SPEAKER | |
| 
 | POWER | PROTECT | 
BRIDGED
B IDGED
TO BATTERY + 12 Volts VIA FUSE REMOTE 

 CHASSIS GROUND
 CHASSIS GROUND
OR HIGHS
SPEAKERS
6
