JBL A6000GTi, Service Manual, Page: 32 / 62

137159-1 Rev. 1 A6000GTi Service Manual

2003 Crown Audio, Inc.
Maintenance 4-13
4.6.1. Quiescent Current Draw
Spec : 12 amps
Procedure : with no load connected, turn amplifier on. Measure the DC current draw of
amplifier. It should be approximately 12 amps.
4.6.2. Sensitivity
Spec : 0.25mV to 8V
Procedure : No load. Inject 0.25 mVrms, 100 Hz sine wave into both RCA inputs. Adjust
sensitivity pot to full clockwise. Measure output voltage on channel 1. Should measure
77.4Vrms. Adjust sensitivity pot full counter clockwise. Inject 8 Vrms, 100 Hz sine wave
into both RCA inputs. Measure output voltage on channel 1. Should measure 77.4Vrms.
4.6.3. Bridge Mono Operation
Spec : Same voltage on both channels, channel 2 out of phase.
Procedure : No load. Switch the unit to bridged mode. Inject a 100 Hz sine wave into one
input. Monitor both outputs of the amplifier. They should be the same voltage and 180
degrees out of phase with each other.
4.6.4. Frequency Response
Spec : ± 3dB from 20 Hz to 200 Hz.
Procedure : Load channels with 2 ohms. Inject a 0.1Vrms, 100 Hz sine wave. Measure the
output voltage. This is your reference level. Change the input frequency to 20 Hz. Verify
that the output is within 3 dB of the reference. Change the input frequency to 200 Hz.
Verify that the output is within 3 dB of the reference.
4.6.5. Short Circuit Test
Spec : Amplifier will protect itself.
Procedure : Inject a 100 Hz sine wave. Short the outputs of the amplifier. The signal lights
should flash every three seconds. Remove the short. The signal lights should stop
flashing.
4.6.6. Output Power
Spec : Each Channel 3000 watts into 2 ohms less then 0.1% THD
Bridge Mode 6000 watts into 4 ohms less then 0.1% THD
Parallel Mode 6000 watts into 1 ohm less then 0.1% THD
Procedure Each Channel : Load each channel with 2 ohms. Inject a 100 Hz signal.
Increase the input until the output reaches 77.5 volts. THD should be less then 0.1 %
Procedure Bridge Mode : Load the amplifier with 4 ohms from Ch1+ to Ch2-. Inject a 100
Hz signal. Increase the input until the output reaches 155 volts. THD should be less then
0.1%