Operation Manual
I-Tech HD DriveCore Series Power Amplifiers
page 38
I-Tech HD DriveCore Series Power Amplifiers
Operation Manual
page 39
7.7.11 LevelMax Suite
This is a suite consisting of a peak voltage limiter, average power limiter, clip limiter and thermal
transducer limiter. First you will set the mode to automatic or advanced:
• Automatic mode:
The software determines the best settings based on the signal characteristics.
You can modify only the RMS threshold, Speaker Thermal threshold and time constant. Everything
else is set automatically.
• Advanced mode:
You can modify the RMS threshold, Speaker Thermal threshold, time constant,
Peak threshold and Peak/RMS release.
Peak Voltage Limiter
This limits the peak voltage output ofthe amplifier.
On:
Enables or disables this function. You’ll set the parameters below:
• Threshold:
Sets the level, in absolute voltage, which the limiter will allow from the amplifier. The
range is from 12 V
pk
to 255 V
pk.
• Attack Time
: Sets the attack time of the limiter. The attack time is defined as the time it takes the
limiter to attenuate the output signal by 20 dB. The range is from 1 millisecond to 100 milliseconds.
The Instant setting attack time is instant (0 millisecond).
•
Release Time:
Sets the release time of the compressor. The release time is defined as the time it
takes the limiter to increase the output signal by 20 dB. The range is from 10 milliseconds to 10
seconds.
Average Power Limiter
This limits the long-term output power of the amplifier. You’ll set the parameters below:
• Threshold:
Sets the average power level, in watts, which the limiter will allow from the amplifier
channel. The range is from 10 watts to 10,000 watts. This level should be set to the connected
loudspeaker’s long-term power rating. Also you must enter the loudspeaker’s nomi nal impedance.
• Attack Time:
Sets the attack time of the limiter. The attack time is defined as the time it takes the
limiter to attenuate the output signal by 20 dB. The range is from 1 second to 30 seconds.
• Release Time:
Sets the release time of the compressor. The release time is defined as the time it
takes the limiter to increase the output signal by 20 dB. The range is from 1 second to 30 seconds.
Clip Eliminator:
This limiter monitors the clip events and attenuates the input signal to prevent
amplifier clipping. The attack and release times are preset to optimum rates. Only one parameter
controls this limiter. “Enable”
enables or disables this limiter.
A lookahead feature prevents overshoot of the limiters. These settings were developed with JBL to
protect the speakers from overvoltage.
Transducer Thermal Limiting
This limits the long-term output power of the amplifier to what the loudspeaker load can handle
without overheating and going into thermal compression. You can set the thermal level at which the
thermal limiter engages, the thermal response time and thermal voltage. Your loudspeaker
manufacturer might be able to provide this information. Meters show the amplifier output level in
dBFS; and peak, rms, and total gain reduction.
7.8.12 Front Panel Security
Here you can choose which amplifier LCD screens to lock so they can’t be changed.
7 Advanced Operation
7.7.13 Amplifier Settings
The
Amplifier Output Enable
button turns each channel on
or off.
Error Reporting
The I-Tech amplifier can detect four different error conditions
per channel and errors in the AC line voltage. Each error type
can be indi vidually configured to report the error through the
network. Network reported errors appear in the control software
Event Log. The following describes each error source.
Clip:
A clip detector is provided each channel. These monitors
will indicate any clip condition (> 0.05% distortion) in the
amplifier channel. The clip detectors also can indicate Thermal
Level Control limiting.
The I-Tech HD can be configured to report if an excessive
number of output clip events occur in either amplifier channel.
The clip events are considered an error if they exceed the
defined count per the defined unit of time.
The
Count
Control sets the maximum number of events before
the error is reported. The range is 1 to 100. The
Time
Control
defines the amount of time that the events are counted before
starting the counting process over. Its range is 1 to 10 seconds.
Note: Clip events are defined as the start of each clip and every
10 milliseconds the amplifier is in clip thereafter. Using a high
count set ting with a short time setting may result in clip errors
never being detected.
Thermal:
Errors can be generated for excessive temperature
in the output section of the amplifier channel. The
Threshold
Control sets the level that, if exceeded, will generate the error
report. This control has a range of 1 to 100%.
Line voltage:
The AC line voltage can be monitored and an
error generated whenever the voltage is outside of the limits set
by the soft ware.
Fan:
Using the ON button, you can enable reports of any fan
errors.
Continuous Load Monitoring
The load supervision feature allows real-time monitoring of the
load connected to each amplifier channel. When enabled, the
I-Tech contin uously monitors the amplifier output voltage and
current, and calcu lates the long-term average load impedance.
The measured load impedance is compared against the
user-defined high and low limits. If either limit is exceeded, the
status indicator and, if enabled, the System Architect Error
Reporting functions alert the user of the problem. There are six
controls and two indicators for each channel:
On:
Enables or disables the load-supervision function.
Load Status:
This indicator shows the present sta tus of the
load impedance with respect to the user-defined high and low
limits.
Average Impedance:
Shows the average impedance for the
connected load.
High Limit:
Sets the upper bound above which the system
will report a “high” error status.
Low Limit:
Sets the lower bound below which the system will
report a “low” error status.
Nominal Impedance:
Sets the expected average impedance
for the connected load. This value determines the output signal
level required for the test. This parameter is also used by the
average power limiter to determine the expected power
threshold. You set this field to the nominal impedance of the
connected load per channel.
Report Errors via Network:
When this is turned on, high
and low load errors are sent via the network to System Architect
software.
7 Advanced Operation
