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Crown Audio 1201, 2401, MT-601 operation manual Stereo Operation, Circuit Block Diagram

Models: MT-601 1201, 2401

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Micro-Tech Series Power Amplifiers

6 Principles of Operation

6.2.1 Stereo Operation

For simplicity, the discussion of Stereo opera- tion will refer to one channel only. Mono opera- tion will be discussed later. For specific circuit references, see the block diagram in Figure 6.1.

The signal at the ¼-inch phone jack input passes directly to the balanced gain stage (U104-A and U104-B). The balanced gain stage causes balanced to single-ended conversion using a difference amplifier. From there, gain can be controlled with a potentiometer. The error amp (U104-C) amplifies the difference between the output signal and the input signal from the gain pot, and drives the voltage trans- lator stage.

From the error amp, the voltage translator stage routes the signal to the Last Voltage Amplifiers (LVAs) based on signal polarity. The +LVA

(Q105) and the –LVA (Q110), with their push- pull effect through the bias servo Q318, drive the fully complementary output stage.

The bias servo Q318 is thermally coupled to the heat sink and sets the quiescent bias cur- rent in the output stage to lower the distortion in the crossover region of the output signal.

D301, D302, D303, and D304 remove the charge on the unused portion of the output stage based on the polarity of the output signal.

With the voltage swing provided by the LVAs, the signal then gains current amplification through the Darlington emitter-follower output stage.

The bridge-balanced circuit (U104-D) receives a signal from the output of the amplifier and compares it to the signal at the Vcc supply. The bridge-balanced circuit then develops a voltage

to drive the bridge-balanced output stage. This results in the Vcc supply having exactly one half of the output voltage added to their quies- cent voltage. D309, D310, D311 and a trimmer resistor set the quiescent current point for the bridge-balanced output stage.

The protection mechanisms that affect the sig- nal path are implemented to protect the ampli- fier under real-world conditions. These conditions are high instantaneous current, excessive temperature, and output device oper- ation outside safe conditions.

Q107 and Q108 sense output current and act as a common current limiter. When instantaneous current exceeds the design criteria, the limiters remove the drive from the LVAs to limit output current to safe levels.

Figure 6.1 Circuit Block Diagram

Operation Manual

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Crown Audio 1201, 2401, MT-601 operation manual Stereo Operation, Circuit Block Diagram
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MT-601, 1201, 2401 specifications

Crown Audio is synonymous with high-performance amplifiers, and their models 1201, 2401, and MT-601 embody the brand's commitment to quality and reliability in sound reinforcement. Each model caters to different needs, making them valuable assets in live sound and installation applications.

The Crown 1201 amplifier is designed for versatility, providing 120 watts per channel at 8 ohms. This model features Crown's patented "Power Factor Control," which ensures maximum power delivery with minimal distortion and heat generation. The 1201 is lightweight yet rugged, making it ideal for portable applications. It's equipped with comprehensive protection circuitry, including short circuit and thermal protection, safeguarding both the amplifier and connected speakers.

Moving to the Crown 2401, it ups the power with 240 watts per channel at 8 ohms. The 2401 also employs Crown's advanced input circuitry, which enhances audio clarity and reduces noise. Its design includes an intelligent cooling system with variable-speed fans, accommodating demanding situations while ensuring quiet operation. The amplifier's robust build quality and efficient power usage make it a favorite among sound engineers who require both reliability and performance.

The MT-601 is a versatile addition to Crown's lineup, known for its flexibility in various applications. Delivering 300 watts per channel at 8 ohms, the MT-601 features an advanced monitoring system that provides real-time feedback on system performance. This capability allows sound technicians to make adjustments on the fly, optimizing sound quality. The MT-601's lightweight chassis and modern design make it easy to integrate into any setup.

All three models embody Crown Audio's dedication to innovation through technologies such as output peak limiter and gain monitoring, which prevents signal clipping and distortion. They also feature variable-speed cooling fans that adapt based on the amplifier's thermal load, ensuring efficiency without compromising performance.

In summary, Crown Audio’s 1201, 2401, and MT-601 amplifiers showcase the brand’s expertise in delivering powerful, reliable audio solutions. With their unique features, robust build quality, and advanced technologies, these amplifiers meet the diverse needs of both live performance environments and fixed installations, making them an ideal choice for audio professionals.