Maselec MPL-2 Peak & High Frequency Limiter

The MPL-2 is housed in a 1U 19″ rack mount alloy case.

A minimum of controls is used due to automatic time constants and optimisation techniques for the
gain reduction. The advantage is not only simple operation but also increased performance for highly
dynamic and inconsistent materials without the need for continuous readjustments.

The input gain does not reduce the wide dynamic range of the limiter. It can be used at its maximum
setting with no increased risk of distortion. This eliminates the need for excessive levels, which could
cause clipping in equipment feeding the input of the limiter. A further benefit is that the maximum
peak output level (set with the threshold) is independent of different gain settings.

High Frequency Limiting is primarily intended for use as a de-esser, reducing unattractive high
frequencies. Part of the high frequency limiter circuit is also used to reduce distortion from the wideband limiter.

Users of the MPL-2 will notice the removal of spurious peaks, and an increase of subjective levels,
without the coloration and increased distortion so often associated with soft clippers and other ultra
fast limiters.

The MASELEC model MPL-2 limiter was designed to:

• Prevent peak levels from exceeding a pre-set limit.
• Increase subjective loudness of programmes.
• Give digitally recorded programmes a more ‘analogue’ character.
• Introduce a soft ‘levelling’ function for large differences in average programme levels.
• Reduce dynamic range of programmes to maximize the performance of AD converters.
• Add no audible ‘pumping’ resulting from limiting.
• Have a well-defined threshold, with no need for programme related adjustments.

SPECIFICATION

Input dynamic Range……………………. Better than 120dB (balanced)
Output dynamic range…………………… 100dB to 120dB (depending on gain and threshold settings)
Maximum input level…………………….. +29dBu (balanced)
Maximum output level…………………… +29dBu (balanced)
Distortion…………………………………….. Typically less than 0.003%
Limiter attack time………………………… Instant
HF limiter attack time……………………. Programme dependent 1msec to 20 msec
Release time……………………………….. Programme dependent
Input impedance………………………….. 100kΩ ground floating electronically balanced
Output impedance…………………..…… 33Ω electronically balanced
Threshold……………………………………. +14dBu to +22dBu
H.F. Threshold…………………………….. 0dB to 26dB below limiter threshold
Gain…………………………………….…….. 0dB to 10dB
H.F. Limiter…………………………………. >2kHz
Power………………………………..…….… 90-130, 180-260 Volts @ 50-60 Hz
Fuse……………………………………………315mA, anti surge (slow)