6. Signal Flow and Lake® Processing
PLM+ SERIES Operation Manual rev
3.0.1
29
6.2. Level Adjustments & Mute Points
1 Input Router Stage
Input selection and MUTE
2 Input Mixer Stage
Router on /off connection to mixer and gain settings
3 Module Input Stage
Mute (N/A for LM Series Mesa Mode) and gain settings
4 Module Output Stage
Mute and gain settings
5 Output Router Stage
Output on /off routing connections
6 Attenuation Stage
Power output channel mute and attenuation settings
7 Amp Gain Stage
Amplifier gain control
NOTE: If the required audio signal is not passing correctly, verify the connection, mute and gain settings
at all seven stages.
6.2.1. Power Output Section: Limiting and Sensitivity
The Current Peak Limiter (CPL) dynamically limits the drive to the power stage based on three parameters: sensed
output current level, feedback from the output stage, and sensed voltage clip from the ISVPL. This ensures that
power output is maintained within the design limits of the PLM+.
The adjustable Inter-Sample Voltage Peak Limiter (ISVPL) sets the PLM+’s maximum output voltage and therefore
also the maximum output power. The ISVPL setting is made via MENU > MODULE > LIMITERS > ISVPL, and can
also be set from the Lake Controller software.
The sophisticated output section monitors faults and generates warnings when appropriate; warnings are
displayed on the front panel of the PLM+ and also sent as messages over the control network. In the rare event
that maximum ratings are significantly exceeded, the PLM+ will mute until the condition has been rectified or
the incorrect setting has been readjusted. Sensing circuits also transmit local output power stage temperature,
processor card temperature, and PSU temperature to the appropriate protection circuits. Please refer to section
5.3 further details.
Table 6.2 lists PLM+ Series analog input sensitivity in dBu and Vrms for various Amp Gain settings and maximum/
minimum ISVPL settings, assuming an analog input headroom of 26 dBu.
Table 6.2: Analog Input Sensitivity in dBu and Vrms
Input Sensitivity
L
ISVPL SETTING
194 V
17.8 V
L
GAIN (dB)
+44
+1.0
0.87
-19.8
0.08
+41
+4.0
1.22
-16.8
0.11
+38
+7.0
1.73
-13.8
0.16
+35
+10.0
2.44
-10.8
0.22
+32
+13.0
3.45
-7.8
0.32
+29
+16.0
4.87
-4.8
0.45
+26
+19.0
6.88
-1.8
0.63
+22
+23.0
10.90
+2.2
1.00
