Setup Disc: The included setup CD is used to optimize the
input gain. A test tone is output from the disc and the Gain LEDs on the amp
(green, yellow, red) guide you through adjusting the gain controls.
Note: The instructions in the first
version of the manual indicate the radio should be at full
volume when playing the setup disc; this is wrong
and JBL is in the process of correcting the manual. The volume
should actually be as high as possible without distorting the
signal; this will be different for every radio, but approximately
3/4 volume is typical.
Auto Turn-on: The GTO-501EZ has a signal sensing automatic
turn-on circuit; it will turn on whenever an audio signal is present at the RCA
inputs. The amplifier will automatically turn off approximately five minutes
after the input signal ceases. If you prefer to use the radio's remote lead,
the auto turn-on feature can be turned off.
Crossovers: Because this is a subwoofer amplifier, the
low-pass crossover cannot be bypassed. The crossover point is continuously
variable from 40 Hz to 280 Hz and the crossover's slope is 12 dB/octave.
Audio Input: If your radio has no line-level outputs, use
the included adapters to convert the speaker wires to RCA and plug them into
the amplifier's inputs. The input level switch has a Hi2 position, used
to present a speaker load to factory radios equipped with a circuit that turns
the radio off when an amp is connected.
- Crossover Frequency: rotary knob;
continuously variable from 40 Hz to 280 Hz
- Input Gain: rotary knob (the gain
LEDs are above the knob)
- Bass Boost: rotary knob; continuously
variable from 0 to +12 dB; boost centered at 45 Hz
- Input Level: three position switch;
Low, Hi1, or Hi2 (used only with factory radios having a
circuit that turns the radio off when it sees no speaker
- Gain LEDs: on/off
- Power and Ground Terminals: set screw
terminals; accept up to 4 gauge bare wire
- Note: JBL recommends the power and ground
cables be 8 gauge minimum.
- Remote Turn-on Terminal: set screw
terminal; accepts up to 8 gauge bare wire
- Speaker terminals: one pair of set
screw terminals; accepts up to 8 gauge bare wire
- Fuses: two ports for 25-amp ATO fuses
(fuses are factory installed)
- Audio Input: left and right female RCA
jacks; compatible with a speaker level signal using the
- Remote: RJ-25 jack (the wired remote
is not yet available as of 2/16/12)
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