M Series Power Amplifiers

5 Principles of Operation

For the sake of simplicity, only channel one of the amplifier is described.

Signal is presented to the M120 and M240 through one of three connectors when using the standard input module. Each channel is outfitted with a balanced XLR / phone jack, and a barrier strip. These connectors are wired in parallel, which allows daisy chaining when needed. The signal is then converted from bal- anced to unbalanced in the Balanced Input Stage where it also receives RFI protection. Signal then flows into the Variable Gain Stage where the front panel level controls are allowed to affect the gain.

Following this stage, the signal is put under the control of a full-time compressor circuit com- prised of a symmetrical window detector, a buffer amplifier, and the gating op amp which uses several small components to set the com- pressor’s attack and decay characteristics. The actual compressing is accomplished by an opto-isolator which affects the gain in the sig- nal path.

The signal next enters the main amplifier error amp where it is mixed with a small portion of the output signal in such a way as to control the amplifier’s overall output performance. Following the error amp is the LVA stage, which is where the low-voltage referenced signal gets translated to the output high-voltage rails. The

last voltage amplifier, in conjunction with a bootstrapped current source, drives both pre- drivers and the bias servo. The bias servo is mounted in such a way as to translate the out- put heatsink temperature into a controlled bias current to prevent thermal runaway and hold the amplifier’s notch distortion to a minimum. The predrivers provide enough signal to acti- vate the drivers, which together operate in the class AB range. For the major output current requirements, the drivers feed the various num- bers of paralleled output transistors which operate in a class B mode. This we call the Tri- ple-Deep Darlington Output Stages.

+HI-VOLTAGE BOOTSTRAP

Figure 5.1

M-Series Amplifier

Block Diagram (Shown with Stan- dard Input Module)

BALANCED

INPUTS

TO CLIP

 

COMPRESSOR

INDICATOR

 

CONTROL

 

 

 

 

 

 

 

TRANSLATOR

BALANCE

VARIABLE

BUFFER

ERROR

 

 

AMP

 

GAIN STAGE

 

–VCC

INPUT STAGE

 

 

 

 

 

 

 

TO SIGNAL

PRESENCE

INDICATOR

DC PROTECT

LOGIC

TO

FAULT

CONNECTOR

 

 

 

 

TURN-ON

 

 

 

 

DELAY

CURRENT

 

 

 

 

SOURCE

TRIPLE-DEEP

HEATSINK

 

 

 

 

DARLINGTON

TEMPERATURE

 

 

NPN POSITIVE

 

 

 

 

OUTPUT STAGE

 

 

+

 

 

 

 

 

TDVI

 

OUTPUT

BIAS

 

CONTROL

LIMITER

 

 

 

 

OUTPUT

 

TRIPLE-DEEP

 

 

 

 

DC

 

 

DARLINGTON

 

 

LVA

NPN NEGATIVE

 

PROTECT

 

 

OUTPUT STAGE

 

 

 

–VCC

HEATSINK

TRANSFORMER

TO FAULT

TEMPERATURE

 

 

TEMPERATURE

INDICATOR

 

PROPORTIONAL

 

+ VCC

 

 

SPEED

POWER

 

 

+ 15V

 

 

FAN

 

 

 

 

 

 

CONTROL

SUPPLY

– 15V

 

 

 

 

– VCC

 

 

FAN

 

BOOTSTRAP

+ HI-VOLTAGE

 

 

CIRCUIT

BOOTSTRAP

MUTE

page 16

Operation Manual

Page 16
Image 16
Crown Audio M Series operation manual Principles of Operation, Series Amplifier

M Series specifications

Crown Audio's M Series amplifiers are a renowned collection in the realm of professional audio equipment, recognized for their reliability, performance, and innovation. Designed specifically for commercial installations, the M Series provides powerful amplification with exceptional audio quality, making it a prime choice for venues such as auditoriums, churches, and theaters.

One of the standout features of the M Series is its high-efficiency Class D topology. This design not only reduces power consumption but also minimizes heat generation, which is crucial for long-term reliability and performance in demanding environments. The amplifiers are capable of delivering high output power while maintaining low distortion, ensuring that the audio experience remains clear and robust, even at high volumes.

The M Series amplifiers are equipped with a range of power options, ensuring that users can find a model that suits their specific needs. The lineup typically includes models ranging from 2-channel to 4-channel configurations, with power ratings suitable for various applications. This versatility allows for flexible setups, whether powering large PA systems or smaller setups for more intimate settings.

Integration with control systems is effortless, thanks to the M Series’ comprehensive connectivity options. The amplifiers feature XLR and TRS inputs, allowing for seamless integration with a wide array of audio sources. Their ability to be controlled remotely allows for convenient adjustments during live events or installations, further enhancing their usability.

The built-in DSP (Digital Signal Processing) is another critical highlight of the M Series. This technology provides users with significant control over the audio signal, enabling adjustments such as equalization, limiting, and crossover settings to fine-tune the sound output to perfection. The advanced protection circuitry ensures that the amplifiers remain safe from overheating and signal overloads, thus extending their lifespan and reliability.

Robust construction is a signature characteristic of the M Series, designed to withstand the rigors of professional use. The amplifiers feature a rugged chassis that can endure the demands of touring or permanent installations. Additionally, the fan-cooled design aids in maintaining optimal operating temperatures, ensuring performance consistency even during extended periods of use.

In conclusion, Crown Audio's M Series amplifiers combine power, efficiency, and cutting-edge technology to create an exceptional solution for professional audio applications. Whether used in concert halls, clubs, or corporate environments, the M Series continues to set a high standard for reliability and performance in the world of audio amplification.