Level Controls; Current Limit; Slew Rate & 10 Khz Square Wave; Crosstalk - Crown Macro-Tech MA-3600VZ Service Manual

130366-1 Rev. A
4.3.9 Test 8: Level Controls
Spec: Level controlled by level controls.
Initial Conditions: Controls per standard.
Procedure: No Load. Inject a 1 kHz sine wave.
With level controls fully clockwise you should see
full gain. As controls are rotated counterclockwise,
observe similar gain reduction in each channel. When
complete, return level controls to fully clockwise
position.
4.3.10 Test 9: Current Limit
Spec: Current Limit at 43 - 48 Amps
Initial Conditions: Controls per standard.
Procedure: Load each channel to 1 Ohm. Inject a 1
kHz differentiated (or 10% duty cycle) square wave.
See fi gure 4.1. Increase output level until current limit
occurs. Current limit should occur at 43 - 48 Amps
(43-48 Vpk). Disregard waveform overshoot. Observe
clean (no oscillations) current clipping. See Figure 4.2
for differentiated wave form at current limit.
4.3.11 Test 10: Slew Rate & 10 kHz Square Wave
Spec: 30 - 40 V/µS.
Initial Conditions: Controls per standard.
Procedure: Load each channel to 8 ohms. Inject a
10 kHz square wave to obtain 90 volts zero-to-peak at
each output. Observe the slope of the square wave.
It should typically measure 30 to 40 V/µS. Also, the
square wave must not include overshoot, ringing, or
any type of oscillation. See Figure 4.3 for typical 10
kHz square wave response.
4.3.12 Test 11: Crosstalk
Spec: -60dB at 20 kHz.
Initial Conditions: Controls per standard. Terminate
input of channel not driven with 600 ohms.
Figure 4.3 10 kHz square wave response
©2000 Crown International, Inc.
Procedure: 8 ohm load on each channel. Inject a 20
kHz sine wave into the Channel 1 input and increase
output level to 80 VAC. Measure less than 80 mVAC
at the output of Channel 2. Inject a 20 kHz sine wave
into the Channel 2 input and increase output level to
80 VAC. Measure less than 80 mVAC at the output
of Channel 1.
4.3.13 Test 12: Output Power
Spec at 8 Ohm Stereo: ≥ 1125W at 0.1% THD.
Spec at 4 Ohm Stereo: ≥ 1625W at 0.1% THD.
Spec at 2 Ohm Stereo: ≥ 1800W at 0.1% THD.
International 8 Ohm Stereo: ≥ 945W at 0.1% THD.
International 4 Ohm Stereo: ≥ 1255W at 0.1% THD.
International 2 Ohm Stereo: ≥ 1490W at 0.1% THD.
Initial Conditions: Controls per standard.
Procedure: Load each channel to 8 ohms. Inject a
1 kHz sine wave and measure at least 94.67 VAC at
the output of each channel. Load each channel to 4
ohms. Inject a 1 kHz sine wave and measure at least
80.62 VAC. Load each channel to 2 ohms. Inject a
1 kHz sine wave and measure at least 60.00 VAC.
All power measurements must be at less than 0.1%
THD. For international units, calculate output voltage
with above power specifi cations.
4.3.14 Test 13: Reactive Loads
Spec: No oscillations. Safe with all types of loads.
Initial Conditions: Controls per standard.
Procedure Capacitive: Load each channel to 8
ohms in parallel with 2 µF. Inject a 20 kHz sine wave
with 48 VAC output for 10 seconds.
Procedure Inductive: Load each channel to 8 ohms
in parallel with 159 µHenries. Inject a 1 kHz sine wave
with 36 VAC output for 10 seconds.
Figure 4.4 ODEP limiting wave form
MA-3600VZ Service Manual
Mantenance 4-3