Operation Manual
4 Channel Amplifier - Speaker & RCA-Connection
GTR250.4 – GTR350.4
Frontspeakers 2 - 8 Ohms
Rearspeakers 2 - 8 Ohms
Connect RCA outputs
from head-unit with
RCA inputs (LINE
INPUT CH1/2 & CH3/4).
X-OVER SWITCH & CONTROL (CH1/2 & CH3/4)
• If larger than 20 cm speakers are used, the "FULL" position is recommended.
For all smaller speakers (8.7cm - 16cm) the "HP"-Position (HIGH PASS) is recommended, which eliminates the lowest
frequencies and protects the speakers from damage. Set the crossover-frequency between 60Hz - 150Hz, depending of the size
of the installed speakers. The Highpass adjustment can be done with the "HP" (HIGH PASS) control.
In this configuration example the "LP" (LOW PASS) control is not used.
LEVEL (CH1/2 & CH3/4)
• Turn the LEVEL controls on the amplifier to 5V position.
• Turn the head unit volume control to about 80-90% of its full setting.
• Turn the LEVEL controls clockwise until you hear some distortion.
• Then turn back the LEVEL controls slightly until you can hear clean sound.
BASS BOOST (CH1/2 & CH3/4)
• Turn the BASS BOOST control into “0dB” - position.
INPUT MODE (CH1/2 & CH3/4)
• The INPUT MODE switch must be in “CH4” - position.
ï
ï
CH3/4
CH1/2
LINE INPUT
R
R
L
L
LINE OUTPUT
LEVEL
5V
60Hz
60Hz
30Hz
30Hz
250Hz
250Hz
0dB
0dB
12dB
12dB
BASS BOOST
INPUT MO DE
2CH
4CH
X-OVER
0,2V
1.2kHz
1.2kHz
LP
BASS BOO ST
LEVEL
5V
0,2V
X-OVER
HP
FULL
HP
LP
HP
LP
CH3 / CH4
CH1/ CH2
3CH
LP
HPFULL
CH3 CH4
CH1 CH2
HIGH
INPUT
---
++
--
--
++
--
+++++
+++++
-----
-----
S
EAKE
R
P
O
UTP
U
T
e
1
3
225
01 7
F
U
S
E
BR
E
DI
G
D
L
R
G
N
D
R
E
M
1
2
V
WE
P
O
R
P
IN
UT
B
D
G
RI
E
D
L
R
R
P
O
T
T
E
C
P
EO
W
R
19
Caution
Please avoid to connect speaker (-) to the ground or vehicle chassis.
4-Channel-Mode: 2 Frontspeakers / Stereo & 2 Rearspeakers /Stereo
Cable connection
• Connect INPUT of the amplifier to the head unit line output with good quality RCA cables.
If your head unit doesn't have RCA Outputs you can connect the Speaker Outputs of the head
unit with the HIGH INPUT of the amplifier.
• Connect the speakers with the terminal block (CH1 +/- und CH2 +/ - SPEAKER) and
(CH3 +/- und CH4 +/ - SPEAKER) of the amplifier.
• The minimum final speaker impedance must not be below 2 Ohm per channel pair. Too low
speaker loads result in too high heat dissipation and may cause the amplifier run into
protection.
• Please observe speaker channel and polarity as printed by the speaker terminal block.
Incorrect phasing of the speakers results in total loss of bass response.
•
•
•
Green: Left Speaker -
White: Left Speaker +
Black: Ground
Brown: Right Speaker +
Gray: Right Speaker -
HIGH LEVEL INPUTS
CH1/2 & CH3/4
REV. 2