22
USA•364
System Configuration #3:
•Two pairs of stereo inputs
•Four channels driving satellites in high pass
•Low pass RCA outputs to an external amplifier driving a subwoofer
•Internal crossovers used
HINT: 12 dB/Oct 75 Hz low pass output
from the USA•364 plus 12 dB/Oct 75 Hz
low pass internal crossover on the
USA•180 sums to 24 dB/Oct 75 Hz low
pass filter!
7
Key to Callouts
1. +12V -Connected to fuse or circuit breaker, then battery’s positive post.
2. Ground -Main ground connection. Bolt to a clean chassis ground in the
vehicle.
3. Remote -Remote turn-on input from the head unit. Accepts +12V.
4. LED -Indicates amplifier power on.
5. Speaker Output Connections -Channels 1 & 2
6. High Pass Crossover Output -Low level high pass outputs to auxiliary
amplifier.
7. Bass EQ -Adjustable bass equalization circuit, 0 to +9 dB boost at 45 Hz—
Channels 1 & 2.
8. Input Level -Variable from 100mV to 2.5V—Channels 1 & 2.
9. Inputs -Right and left channel inputs; only right channel input used in “Mono”
mode—Channels 1 & 2.
10. Speaker Output Connections -Channels 3 & 4
11. Low Pass Crossover Output -Low level low pass output to auxiliary
amplifier.
12. Bass EQ -Adjustable bass equalization circuit, 0 to +9 dB boost at 45 Hz—
Channels 3 & 4 & low pass output.
13. Input Level -Variable from 100mV to 2.5V—Channels 3 & 4.
14. Inputs -Right and left channel inputs; only right channel input used in “Mono”
mode—Channels 3 & 4.
15. [underside] Main Fuse-Main power supply fuse. Replace only with same
fuse value.
16. [underside] Xover S.I.P.s -Crossover frequency settings for amplifier and
outputs—Channels 1 & 2 & high pass and low pass outputs.
17. [underside] Xover S.I.P.s -Crossover frequency settings for amplifier and
outputs—Channels 3 & 4 & low pass outputs.
18. [underside] Stereo/Bridged Mono Switch -Select “Mono” for bridged
operation (use only right channel input) or “Stereo” for 2-channel Stereo or
Mixed Mono operation; See crossover section for more details—Channels 1 &
2.
19. [underside] Amplifier Crossover Switch -Select high pass, low pass, or full
range operation—Channels 1 & 2.
20. [underside] Bass EQ Switch -On/Off switch for bass equalization circuit—
Channels 1 & 2.
21. [underside] Stereo/Bridged Mono Switch -Select “Mono” for bridged
operation (use only right channel input) or “Stereo” for 2-channel Stereo or
Mixed Mono operation; See crossover section for more details.
22. [underside] Amplifier Crossover Switch -Select high pass, low pass, or full
range operation—Channels 3 & 4.
23. [underside] Bass EQ Switch -On/Off switch for bass equalization circuit—
Channels 3 & 4.
24. [underside] Input Select -Selectable inputs from internal (from channels 1 &
